JP2009054289A - Anode material, its manufacturing method, and fuel cell using anode material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive carbon nano-hetero anode material carrying an oxide available with respect to CO oxidizing activity and prices, and also to provide its manufacturing method. <P>SOLUTION: A mixture of undoped CeO<SB>2</SB>powder having: a specific surface area of not less than 1×10 m<SP>2</SP>/g and not more than 1×10<SP>2</SP>m<SP>2</SP>/g; SnO<SB>2</SB>powder having a specific surface area of not less than 10 m<SP>2</SP>/g and not more than 1×10<SP>2</SP>m<SP>2</SP>/g; and Pt having an average secondary particle diameter of not more than 30 nanometer, which does not dissolve conductive carbon and components such as rare earth elements, is used as the anode material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an anode electrode of a fuel cell using a flammable alcohol such as methanol and a method for producing a material constituting the anode electrode.

The Pt / conductive carbon anode material is a typical electrode material used as an electrode material for polymer fuel cells. Although the electrode made of this material shows high electrode activity, it has a usage limitation that it is necessary to use high-purity hydrogen as a fuel.
As a cause of this, when a small amount of combustible impurities are mixed in the fuel used for fuel cell power generation, the combustible components burn on the surface of platinum (Pt), and carbon dioxide (CO ₂ ) and carbon monoxide (CO It is known that CO is adsorbed very strongly on the Pt surface even if it is in a very small amount, and the activity of the Pt surface is significantly reduced (non-patent document). 1).

  In recent years, attempts to use a fuel cell as a power source for portable devices have been extensively studied. In this case, it is common to use a flammable alcohol such as methanol instead of hydrogen as the fuel. A fuel cell that uses methanol as a fuel and supplies methanol directly into the fuel cell as a fuel is called a direct methanol fuel cell. In this fuel cell, the performance of the Pt electrode is reduced by the CO described above. It is considered important to overcome the problem of (CO coating phenomenon).

  Therefore, conventionally, as an anode electrode for a direct methanol fuel cell, alloy nanoparticles are produced between metal elements such as Pt and metal ruthenium (Ru), metal iron (Fe), and metal manganese (Mn). By dispersing nano-sized alloy particles on conductive carbon, the CO coating phenomenon of Pt itself is reduced, and efforts are made to use flammable alcohols such as methanol and ethanol as fuel (Non-patent Document 2).

When such an alcohol is used as a fuel, a large amount of hydrogen and CO is generated on the Pt surface. By forming an alloy with a metal such as Ru, Fe, or Mn, the electron on the Pt surface is an alloy component metal such as Ru. By being strongly attracted to the side, the bond between Pt and CO is weakened. Moreover, active hydroxide ions activated on an additive metal element such as Ru oxidize CO adsorbed on the Pt surface to produce CO _2. Therefore, it is possible to use the fuel cell for a long time without reducing the electrode activity with high Pt.
However, the Ru metal to be added is rare and difficult to obtain (expensive), and the oxidation activity of CO is not yet sufficiently high. Other inexpensive compounds such as iron oxide and manganese oxide also have high CO oxidation as high as Ru. Since it has not been shown to be active, the use of such an anode material composed of Pt / second component / conductive carbon has not yet been put into practical use.

M.M. Watanabe, et al. , Denki Kagaku, 38, 927-932, 1970, published by the Electrochemical Society Masanori Watanabe, Catalysis and Catalyst, Vol. 44, No. 3, pp. 182-188, 2002, published by the Catalysis Society of Japan

As described in the background art, the conventional Pt / second component / conductive carbon-based anode material has several problems such as CO oxidation activity and cost. The present invention is intended to provide a Pt / CeO ₂ .SnO ₂ / conductive carbon nanoheteroanode material free from such problems and a method for producing the same.

  In light of the above-described problems of the prior art, the present inventors have intensively studied and, as a result, have obtained the following invention.

The anode material of the invention 1 includes conductive carbon and an undoped CeO ₂ powder that does not dissolve a component such as a rare earth element and has a specific surface area of 1 × 10 m ² / g or more and 1 × 10 ² m ² / g or less. And a mixture of SnO ₂ powder having a specific surface area of 1 × 10 m ² / g or more and 1 × 10 ² m ² / g or less and Pt having an average secondary particle size of 30 nanometers or less. 1 is satisfied.
(Chemical formula 1)
XPt / Y (ACeO _2. (1-A) SnO ₂ ) / Zcarbon
(In the formula, X, Y, Z, and A represent the content ratios of platinum (Pt), CeO ₂ , SnO ₂ , and carbon, respectively, and 5 × 10 ⁻² ≦ X ≦ 4 × 10 ⁻¹ 1. × 10 ⁻¹ ≦ Y ≦ 3 × 10 ⁻¹ , Z = 1−XY, 6 × 10 ⁻¹ ≦ A <8 × 10 ⁻¹ , and Carbon represents conductive carbon)

Invention 2 is a method for producing a material constituting the anode electrode of Invention 1 or 2, and is characterized by the following steps.
Concentration of 1 × 10 ⁻¹ (M) to 5 × 10 ^{−1 in a} cerium nitrate aqueous solution having a concentration of 5 × 10 ⁻² (M) to 8 × 10 ⁻¹ (M). (M) a first step of preparing a ceria precursor by dropping into the following ammonium carbonate or ammonium hydrogen carbonate aqueous solution at a rate of 2.5 ml / min or less;
The ceria precursor obtained in the first step is maintained at that temperature for 2 × 10 hours or more and less than 4 × 10 hours, and is subjected to solid-liquid separation, washed with water and dried to obtain the solid content,
A third step of preparing a calcined to crystalline ceria powder is less than 3 × 10 ² ° C. Ultra 5 × 10 ² ° C. The solid obtained in an oxygen stream atmosphere in the second step,
The ceria powder obtained in the third step was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 1 × 10 ^-2 (M) or 5 × 10 ^-2 (M) hereinafter), the solvent A fourth step of evaporating and drying in an inert gas flow;
A fourth solids obtained in Step 3 × 10 ² ℃ super 5 × 10 below ² ℃ temperature, under a hydrogen stream atmosphere, W / F (sample weight / hydrogen gas flow) 1 × ^{10 -3} ( g · min / ml) to 1 × 10 ⁻² (g · min / ml),
A sixth step in which SnO ₂ powder is physically mixed at room temperature with the powder obtained in the fifth step and then mixed with conductive carbon.

  Invention 3 is a fuel cell characterized in that the anode material of Invention 1 or 2 is a constituent material of an anode electrode.

  The present invention has succeeded in greatly improving the anode electrode characteristics that can be used in direct methanol fuel cells and the like, and in the future, various fuel cells (polymer fuel cells) including direct methanol fuel cells. , Medium temperature operation / oxide fuel cell) and the like, and is expected to greatly contribute to the improvement in performance and long-term stability of excellent performance. In particular, it is expected to contribute greatly to the downsizing, higher output, and lower price of direct methanol fuel cells that have been attracting attention in recent years, and its significance is extremely large and serious.

Here, the anode material of the present invention comprises a conductive carbon, not a solid solution components such as rare earth elements, and a specific surface area of 1 × ^10m 2 / g or more 1 × ¹⁰ 2 ^m 2 / g or less undoped CeO and ₂ powder, the specific surface area and is 1 × ^{10 m} 2 / g or more 1 × ¹⁰ 2 ^m 2 / g or less of SnO ₂ powder, an average secondary particle diameter is a mixture of the following Pt 30 nanometers.

The specific surface area of the CeO ₂ powder must be 1 × 10 m ² / g or more and 1 × 10 ² m ² / g or less. When the specific surface area is below this range, the interaction with Pt and SnO ₂ is reduced. On the other hand, when the above range is exceeded, CeO ₂ is not a fine particle, but has a large amount of nanopores on the porous body and the surface, and on the contrary, a sufficient contact interface with Pt and SnO ₂ is ensured. Disturb.
The specific surface area of the SnO ₂ powder in the anode material must also be 1 × 10 m ² / g or more and 1 × 10 ² m ² / g or less. Below this range, the interaction with Pt and CeO ₂ decreases. On the other hand, when the above range is exceeded, SnO ₂ is not a fine particle, but has a large amount of nanopores on the porous body or surface, and on the contrary, it ensures a sufficient contact interface with Pt and CeO _2. Hinder.

The average secondary particle size of Pt in the anode material is preferably 30 nanometers or less. When the average secondary particle diameter exceeds 30 nanometers, the interaction between Pt, CeO ₂ and SnO ₂ is not sufficiently high, which is not preferable. On the other hand, the average secondary particle diameter of Pt is extremely small. Since this is impossible in practice, the effect disclosed in the present invention will be sufficiently exhibited if the size is about 1 nanometer, so it should be 1 nanometer or more.

Moreover, as the material composition, one satisfying the following (Formula 1) is more preferable.
(Chemical formula 1)
XPt / Y (ACeO _2. (1-A) SnO ₂ ) / Zcarbon
(In the formula, X, Y, Z, and A represent the content ratios of platinum (Pt), CeO ₂ , SnO ₂ , and carbon, respectively, and 5 × 10 ⁻² ≦ X ≦ 4 × 10 ⁻¹ 1. × 10 ⁻¹ ≦ Y ≦ 3 × 10 ⁻¹ , Z = 1−XY, 6 × 10 ⁻¹ ≦ A <8 × 10 ⁻¹ , and Carbon represents conductive carbon)

  Below the above range of X, the amount of Pt, which is the main role of activity expression, is too small. For example, sufficient hydrogen generation from fuel (alcohols such as methanol and ethanol) tends to be difficult. Not desirable. Further, even if it exceeds the range of X, the effect cannot be expected so much, and a large amount of Pt is used, which is undesirable because the price of the material itself increases.

On the other hand, CeO ₂ in the above general formula is considered to release active oxygen which is considered to oxidize CO adsorbed on the Pt surface, and is subjected to a reduction treatment at the same time as Pt on CeO _2. Interaction between Ce and CeO ₂ is strengthened, and the electronic state of the Pt surface is made to be a monovalent state that does not normally appear on the Pt surface, and functions to weaken the bond with CO. Furthermore, since the interaction between SnO ₂ particles and CeO ₂ particles, which will be described later, is also considered to be important in increasing the activity of Pt, if it falls below the above range of Y, this CeO ₂ tends to be insufficient, and CO 2 This is undesirable because the effect of reducing the coating is reduced. On the other hand, if it exceeds the above range, CeO ₂ itself tends to decrease in conductivity, which is not desirable.

A that determines the mutual ratio of CeO ₂ and SnO ₂ is preferably 6 × 10 ⁻¹ ≦ A <8 × 10 ⁻¹ . Below this range, the proportion of CeO ₂ is too small, which is undesirable because the ability to oxidize CO adsorbed on Pt tends to decrease. On the other hand, if it exceeds this range, the effect of adding SnO ₂ having conductivity is not sufficiently exhibited, which is not desirable. Within the above range, a more preferable value of A is 0.3. In this case, it is considered that an oxygen defect structure having a solid solution surface of (Ce ₂ Sn) O _2-x is formed at the interface between CeO ₂ and SnO ₂ . In the phase diagram of CeO ₂ and SnO ₂ , the solid solution (Ce ₂ Sn) O _2-x is considered to be a crystalline phase that exists stably only at high temperatures, but the interface between CeO ₂ and SnO ₂ Then, when it is blended at a ratio of CeO ₂ / SnO ₂ = 2/1 (CeO ₂ / (CeO ₂ + SnO ₂ ) = 0.77), the surface of the above (Ce ₂ Sn) O _2-x solid solution has It is considered that the formation of the oxygen defect structure maximizes the interaction with Pt on CeO ₂ and maximizes the anode performance.

The ratio Z of the conductive carbon is preferably 1 as the sum of the values of X and Y plus Z. Below this ratio, it is not desirable because the conductive properties of the whole anode material tend to be reduced. In addition, the conductivity does not change greatly even when the ratio exceeds the above-mentioned ratio, but the formation of the interface between Pt / CeO ₂ and SnO ₂ is hindered, or the entire surface of Pt / CeO ₂ / SnO ₂ is electrically conductive carbon. Is undesirable because it appears to tend to inhibit the electrode reaction. It is desirable to satisfy the relationship of X, Y, and Z described above.

Further, the following steps were adopted as a method for producing the anode material in the present invention.
Concentration of 1 × 10 ⁻¹ (M) to 5 × 10 ^{−1 in a} cerium nitrate aqueous solution having a concentration of 5 × 10 ⁻² (M) to 8 × 10 ⁻¹ (M). (M) a first step of preparing a ceria precursor by dropping into the following ammonium carbonate or ammonium hydrogen carbonate aqueous solution at a rate of 2.5 ml / min or less;
The ceria precursor obtained in the first step is maintained at that temperature for 2 × 10 hours or more and less than 4 × 10 hours, and is subjected to solid-liquid separation, washed with water and dried to obtain the solid content,
A third step of preparing a calcined to crystalline ceria powder is less than 3 × 10 ² ° C. Ultra 5 × 10 ² ° C. The solid obtained in an oxygen stream atmosphere in the second step,
The ceria powder obtained in the third step was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 1 × 10 ^-2 (M) or 5 × 10 ^-2 (M) hereinafter), the solvent A fourth step of evaporating and drying in an inert gas flow;
A fourth solids obtained in Step 3 × 10 ² ℃ super 5 × 10 below ² ℃ temperature, under a hydrogen stream atmosphere, W / F (sample weight / hydrogen gas flow) 1 × ^{10 -3} ( g · min / ml) to 1 × 10 ⁻² (g · min / ml),
A sixth step in which SnO ₂ powder is physically mixed at room temperature with the powder obtained in the fifth step and then mixed with conductive carbon.

<First step>
In order to produce high specific surface area CeO ₂ particles, first, an aqueous cerium nitrate solution (concentration of 5 × 10 ⁻² (M) to 8 × 10 ⁻¹ (M)) is prepared. The concentration of the raw material aqueous solution is related to the specific surface area of the CeO ₂ particles to be synthesized. Below the range shown in the present invention, the agglomeration of particles becomes large, and it is difficult to obtain a high surface area required for high performance, which is not preferable. On the other hand, when the concentration range is exceeded, a large number of particles having a small pore diameter are generated, and therefore, a low specific surface area is generated, which is not preferable.

This aqueous solution is dropped into an ammonium carbonate or ammonium hydrogen carbonate aqueous solution (both having a concentration of 1 × 10 ⁻¹ (M) to 5 × 10 ⁻¹ (M)), and the aqueous solution temperature is 45 ° C. to 60 ° C. It is preferable that it is below ℃. Below this temperature, the reaction rate of ammonium carbonate or ammonium hydrogen carbonate, which is a precipitant, is low, and precipitation for producing CeO ₂ particles having a high specific surface area is difficult to form in the precipitant, which is not preferable. On the other hand, if the temperature is exceeded, re-dissolution of the precipitate into the solution proceeds, and as a result, a precursor for producing CeO ₂ particles having a high specific surface area is hardly generated in the precipitant, which is not preferable. Furthermore, the concentration of the ammonium carbonate or ammonium hydrogen carbonate aqueous solution as a precipitating agent is preferably 1 × 10 ⁻¹ (M) or more and 5 × 10 ⁻¹ (M) or less. If the concentration of the precipitant is below this range, the reactivity between the ammonium carbonate or ammonium hydrogen carbonate and the cerium solution is low, and it is difficult to form a precipitate for producing CeO ₂ particles having a high specific surface area in the precipitant. . On the other hand, if the concentration of the precipitant exceeds this range, thermal decomposition occurs at a high temperature, and precipitation that causes a decrease in the specific surface area is likely to occur, so that it is difficult to produce CeO ₂ particles having a high specific surface area. This is not preferable.

This dropping rate is preferably a dropping rate of 2.5 ml / min or less. However, even if it falls below 1 ml / min, a higher effect cannot be obtained as compared with the case of 1 ml / min or more. On the other hand, when the concentration exceeds 2.5 ml / min, aggregation of the generated precipitate starts to proceed, so that it is difficult to generate a precipitate for producing CeO ₂ particles having a high specific surface area in the precipitant, which is not preferable.

<Second step>
It is preferable that the precipitate (ceria precursor) obtained in the second step is kept at 2 × 10 hours or more and less than 4 × 10 hours at the above-mentioned temperature to ripen the precipitate. When the aging time is shorter than the above range, it is not preferable because a precursor for producing CeO ₂ particles having a high specific surface area is hardly generated in the precipitant. On the other hand, if this time exceeds the above range (too long), the re-dissolution and re-precipitation of the precipitate are actively repeated, and the precursor for producing CeO ₂ particles having a high specific surface area is contained in the precipitant. It is not preferable because it becomes difficult to be contained in the slag.

<Third step>
The obtained in the second step solid - liquid mixture solid - and liquid separation, followed by washing with water and drying, the resulting precipitate (solids), 3 × 10 ² ℃ super 5 × 10 below ² ℃ Temperature And calcining under oxygen flow to produce crystalline ceria nanopowder.
When the calcination temperature is low, without terminating pyrolysis of sufficiently precursor, unoxidized decomposition reactant remains in the amorphous state, left behind in the CeO ₂ particles, inhibition action of CeO ₂ particles Is not preferable. On the other hand, if the temperature range is exceeded, the specific surface area of the CeO ₂ particles is greatly reduced by thermal decomposition at a high temperature, and the interaction between the CeO ₂ particles and Pt or SnO ₂ is unfavorable. The firing time is not particularly limited, but if it is too short, it is not preferable because the thermal decomposition does not proceed sufficiently as in the case of the low temperature. If the time is too long, there is no improvement in the effect, which is extra. Even when the sintering temperature is set to the lowest temperature, a range of about 1 to 3 hours is desirable. Moreover, when it is set as the maximum temperature, 1/2 hour-1 hour are preferable.

<Fourth process>
Ceria powder obtained in the third step was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 1 × 10 ^-2 (M) or 5 × 10 ^-2 (M) or less), The solvent is evaporated to dryness under an inert gas flow.
If the concentration of the H ₂ PtCl ₆ · 6H ₂ O aqueous solution exceeds the above range, the Pt particles are aggregated, and exchange of necessary electrons with CeO ₂ or SnO ₂ is hindered. Moreover, if it is less than the above range, although it takes an extremely long time to dry the solvent, only a certain effect can be obtained, and this is not industrially preferable, so the concentration is preferably 0.01 M or more.
The solvent is preferably dried at room temperature under an inert gas flow, and drying at a high temperature exceeding the room temperature is not preferable because it causes aggregation of Pt particles.
If drying is performed at a low temperature of 0 ° C. or more and room temperature or less, the volatilization rate of a solvent such as moisture in the drying gas is remarkably slow, and a long time is required for drying. Further, an extremely low temperature of less than 0 ° C. is not preferable because a solvent such as moisture is solidified and a drying effect does not appear.

<Fifth process>
Pt / CeO ₂ (solid content) obtained in the fourth step is W / F (sample weight / hydrogen gas flow rate) 1 in a hydrogen flow at a temperature of more than 3 × 10 ² ° C. and less than 5 × 10 ² ° C. It is preferable to carry Pt on the CeO ₂ surface by calcining at 10 × ^{3 −3} (g · min / ml) to 1 × 10 ⁻² (g · min / ml). Below the above temperature, the Pt surface is not sufficiently reduced, and the Pt + 1 valence electronic state that appears for the first time due to the interaction between Pt and CeO ₂ does not appear on the Pt surface. On the other hand, exceeding the above temperature range is not preferable because aggregation of platinum increases and expected electrode performance does not appear. Further, such a baking treatment is performed under a hydrogen gas flow of W / F (sample weight / hydrogen gas flow rate) of 1 × 10 ⁻³ (g · min / ml) to 1 × 10 ⁻² (g · min / ml). Preferably it is done. If this W / F (sample weight / hydrogen gas flow rate) exceeds this range (hydrogen gas flow rate is too low), not only Pt reduction will not be performed sufficiently, but also cerium chloride will be produced as a by-product. However, the activity is remarkably lowered, which is not preferable. Moreover, even if it falls below this range (the hydrogen gas flow rate is too high), only a reasonable effect can be expected, so the sample may be processed at the lower limit W / F shown here.
The processing time is not particularly limited, but if it is too short, a sufficient effect cannot be expected. If the time is too long, there is no improvement in the effect, which is extra. What is necessary is just to select in the range of 1/2 hour to 2 hours.

<Sixth step>
It is preferable to physically mix the Pt / CeO ₂ and SnO ₂ powder after the fifth step. By simply physically mixing Pt / CeO ₂ and SnO ₂ powder at room temperature, an active interface is established at the interface. Even if this mixing is performed in a heated state, the interface between CeO ₂ and SnO ₂ does not change greatly, and therefore, sufficient physical mixing may be performed at room temperature. The product thus obtained can be mixed with conductive carbon to provide an anode material having excellent performance.

About the fuel cell, wherein the anode material is used for an anode electrode,
The electrode performance is not limited only by the current value of the electrode, and it is also important that the potential at which the methanol oxidation reaction is started (referred to as On Set Potential) is low. This low potential means that oxidation of methanol adsorbed on Pt occurs very easily. Further, by using an anode having a low on set potential as an electrode for a fuel cell, it is possible to reduce anode loss that occurs when generating power from the fuel cell, and to extract a large current density and output from the fuel cell. Thus, on set potential should be sufficiently low. The action of reducing this on set potential appears only when the interaction between Pt / CeO ₂ / SnO ₂ / Pt—CeO ₂ particles and CeO ₂ —SnO ₂ particles in the conductive carbon anode material is combined. Such interaction is possible only with the above-described composition and manufacturing method.

  Next, this invention is demonstrated based on an Example, drawing, and a comparative example. However, these examples are disclosed only as an aid for specifically showing and easily understanding the present invention, and the contents of the present invention are not limited by these examples.

Example 1;
Composition _{30wt% Pt / 19wt% (0.77CeO} 2 0.33SnO 2) / so that 51 wt% C, as a starting material, cerium nitrate 0.4 (M) and (purity 99.99%) 0. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to produce a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder (produced by CI Kasei Co., Ltd.) at room temperature , NanoTek) were physically mixed and then mixed with a predetermined amount of carbon black powder to obtain a powdered anode material.

FIG. 1 shows an X-ray diffraction pattern of the obtained anode material. From the identification result of the crystal phase, it was found that the anode material was composed of three kinds of components of Pt, CeO ₂ and SnO ₂ . The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was subjected to cyclic voltammetry at a scanning speed of 50 mV / s in a mixed aqueous solution of H ₂ SO ₄ solution having a concentration of 0.5 (M) and methanol having a concentration of 0.5 (M). The electrode activity was evaluated.

FIG. 2 shows a cyclic voltammogram of the anode material obtained in this example at 28 ° C. As can be seen from this figure, a peak of a large current value of 2.6 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. The size of this peak serves as an index for measuring the efficiency of conversion of CO generated as a by-product into CO ₂ when hydrogen is generated from methanol. The larger the current value, the more the CO is converted into CO ₂ . Since the reaction means that the reaction proceeds easily, in the anode material obtained in Example 1, addition of methanol to hydrogen and CO occurs, and conversion reaction of CO, which is a by-product, to CO ₂ It has been confirmed that the process proceeds easily and exhibits extremely high electrode activity. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was as low as 0.39 (V vs. RHE) as shown in FIG.
The results obtained in Example 1 are summarized in Tables 1 to 6.

Example 2;
As a starting material, 0.1 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33SnO ₂ ) / 61 wt% C were used. A 2 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 46 ° C. at a rate of 1.2 ml / min to produce a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was carried out at a temperature of 46 ° C. for 20 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 380 ° C. for 2 hours under a flow of oxygen to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.015 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 380 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.002 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain a powdered anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 72 and 60 m ² / g, respectively. Further, the particle diameter of Pt in the produced anode material was estimated from the surface area measured by the CO stripping method to be 31 m ² / g, and the average secondary particle diameter calculated from the surface area was 9 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a large current value of 2.6 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in Example 2 was obtained from methanol to hydrogen. It was confirmed that addition to CO occurred, and the conversion reaction of CO, which is a by-product, to CO ₂ proceeded easily and exhibited extremely high electrode activity. Moreover, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was also sufficiently low as 0.39 (V vs. RHE).
The results obtained in Example 2 are summarized in Tables 1 to 6 as in Example 1.

Example 3;
As a starting material, 0.7 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 30 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 35 wt% C were used. A 4 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 35 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 430 ° C. for 2 hours under a flow of oxygen to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.045M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 430 ° C., Under a hydrogen flow, calcined for 1 hour with W / F (sample weight / hydrogen gas flow rate) of 1 × 10-2 (g · min / ml), and then physically a predetermined amount of SnO ₂ powder at room temperature. After mixing, it was mixed with a predetermined amount of carbon black powder to obtain a powdered anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 38 and 60 m ² / g, respectively. Further, the particle diameter of Pt in the produced anode material was estimated from the surface area measured by the CO stripping method, and as a result, it was 20 m ² / g, and the average secondary particle diameter calculated from the surface area was 13 nm.
The anode material thus obtained was subjected to cyclic voltammetry at a scanning speed of 50 mV / s in a mixed aqueous solution of H ₂ SO ₄ solution having a concentration of 0.5 (M) and methanol having a concentration of 0.5 (M). The electrode activity was evaluated.

The cyclic voltammogram of the anode material obtained in this example at 28 ° C. shows the same shape as that in FIG. 1 of Example 1, and 2.8 mA / cm, which shows methanol oxidation at a potential of 0.82 V vs RHE. the peak of the large current of ² was confirmed. The size of this peak serves as an index for measuring the efficiency of conversion of CO generated as a by-product into CO ₂ when hydrogen is generated from methanol. The larger the current value, the more the CO is converted into CO ₂ . Since the reaction means that the reaction proceeds easily, in the anode material obtained in this example, addition of methanol to hydrogen and CO occurs, and conversion reaction of CO as a byproduct to CO ₂ occurs. It has been confirmed that the process proceeds easily and exhibits extremely high electrode activity. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol occurs easily, was as low as 0.39 (V vs. RHE).
The results obtained in Example 3 are summarized in Tables 1 to 6.

Example 4;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.65 CeO ₂ 0.35 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 58 ° C. at a rate of 2.4 ml / min to prepare a precipitate. . After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 58 ° C. for 20 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder (produced by CI Kasei Co., Ltd.) at room temperature , NanoTek) were physically mixed and then mixed with a predetermined amount of carbon black powder to obtain a powdered anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material has three types of Pt, CeO ₂ and SnO ₂ . It turned out to consist of ingredients. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was subjected to cyclic voltammetry at a scanning speed of 50 mV / s in a mixed aqueous solution of H ₂ SO ₄ solution having a concentration of 0.5 (M) and methanol having a concentration of 0.5 (M). The electrode activity was evaluated.

The cyclic voltammogram of the anode material obtained in this example at 28 ° C. shows a shape similar to that of FIG. 2 of Example 1, and 2.4 mA / cm, which indicates methanol oxidation at a potential of 0.82 V vs RHE. the peak of the large current of ² was confirmed. The size of this peak serves as an index for measuring the efficiency of conversion of CO generated as a by-product into CO ₂ when hydrogen is generated from methanol. The larger the current value, the more the CO is converted into CO ₂ . Since the reaction means that the reaction proceeds easily, in the anode material obtained in this example, addition of methanol to hydrogen and CO occurs, and conversion reaction of CO as a byproduct to CO ₂ occurs. It has been confirmed that the process proceeds easily and exhibits extremely high electrode activity. Moreover, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was as low as 0.40 (V vs. RHE).
The results obtained in Example 4 are summarized in Tables 1 to 6.

Example 5;
Composition _{30wt% Pt / 19wt% (0.72CeO} 2 0.28SnO 2) / so that 51 wt% C, as a starting material, cerium nitrate 0.4 (M) and (purity 99.99%) 0. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 46 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was carried out at a temperature of 46 ° C. for 20 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder (produced by CI Kasei Co., Ltd.) at room temperature , NanoTek) were physically mixed and then mixed with a predetermined amount of carbon black powder to obtain a powdered anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material has three types of Pt, CeO ₂ and SnO ₂ . It turned out to consist of ingredients. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. Further, the particle diameter of Pt in the produced anode material was estimated from the surface area measured by the CO stripping method to be 27 m ² / g, and the average secondary particle diameter calculated from the surface area was 10 nm.

The anode material thus obtained was subjected to cyclic voltammetry at a scanning speed of 50 mV / s in a mixed aqueous solution of H ₂ SO ₄ solution having a concentration of 0.5 (M) and methanol having a concentration of 0.5 (M). The electrode activity was evaluated.

The cyclic voltammogram of the anode material obtained in this example at 28 ° C. shows a shape similar to that of FIG. 2 of Example 1, and 2.4 mA / cm, which indicates methanol oxidation at a potential of 0.82 V vs RHE. the peak of the large current of ² was confirmed. The size of this peak serves as an index for measuring the efficiency of conversion of CO generated as a by-product into CO ₂ when hydrogen is generated from methanol. The larger the current value, the more the CO is converted into CO ₂ . Since the reaction means that the reaction proceeds easily, in the anode material obtained in this example, addition of methanol to hydrogen and CO occurs, and conversion reaction of CO as a byproduct to CO ₂ occurs. It has been confirmed that the process proceeds easily and exhibits extremely high electrode activity. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol occurs easily, was as low as 0.39 (V vs. RHE).
The results obtained in Example 5 are summarized in Tables 1 to 6.

Comparative Example 1;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 78 wt% C were used. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to produce a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.
The precipitate (solid content) thus obtained was subjected to water washing treatment and filtration alternately three times, then ethanol treatment and filtration alternately repeated twice, and dried in dry nitrogen gas for 2 days. A powder was prepared. The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a small current value of 0.5 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in Comparative Example 1 was obtained from methanol to hydrogen. Although the addition to CO occurred, the conversion reaction of CO, which is a byproduct, to CO ₂ hardly occurred, and it was confirmed that extremely low electrode activity was exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a high value of 0.52 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 1 are summarized in Tables 7 to 12.

Comparative Example 2;
The starting material was 0.4 (M) cerium nitrate (purity 99.99%) and 0.1% so that the composition would be 20 wt% Pt / 5 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 75 wt% C. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a small current value of 0.8 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol to hydrogen. Although addition to CO occurred, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ did not easily occur, and extremely low electrode activity was exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a high value of 0.51 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 2 are summarized in Tables 7 to 12.

Comparative Example 3;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.5 CeO ₂ 0.5SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a relatively small current value of 1.2 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.48 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 3 are summarized in Tables 7 to 12.

Comparative Example 4;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.85 CeO ₂ 0.15 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a relatively small current value peak of 1.3 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE, and therefore the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.48 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 4 are summarized in Tables 7 to 12.

Comparative Example 5;
Based on the composition of 30 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C, 0% as a starting material was added so that 20 wt% C was added to this blending ratio. .4 (M) cerium nitrate (purity 99.99%) and 0.25 (M) ammonium carbonate aqueous solution (purity 99.5%) were prepared, and the ammonium carbonate aqueous solution heated to 55 ° C. was charged with cerium nitrate. The aqueous solution was dropped at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a comparatively small current value of 1.4 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.47 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 5 are summarized in Tables 7 to 12.

Comparative Example 6;
0.02 (M) cerium nitrate (purity 99.99%) and 0.02 (M) were used as starting materials so that the composition was 30 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 6 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 0.8 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was a relatively high value of 0.52 (V vs. RHE), and it was difficult to initiate methanol oxidation.
The results obtained in Comparative Example 6 are summarized in Tables 7 to 12 as in Comparative Example 1.

Comparative Example 7;
The starting material was 1.2 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO _2. I found out that The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 5 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 0.6 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was a relatively high value of 0.52 (V vs. RHE), and it was difficult to initiate methanol oxidation.
The results obtained in Comparative Example 7 are summarized in Tables 7 to 12.

Comparative Example 8;
As a starting material, 0.4 (M) of cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 05 (M) ammonium carbonate aqueous solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the ammonium carbonate aqueous solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. Although a precipitate was formed, it appeared that a sufficient amount of precipitate was not formed due to the low concentration of the precipitant aqueous solution. After completion of the dropwise addition of the cerium nitrate aqueous solution, aging was performed at a temperature of 55 ° C. for 20 hours.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material showed the same result as that of FIG. 1 shown in Example 1, but the peak intensity of CeO 2 was extremely low. However, from the identification result of the crystal phase, it was found that the anode material is composed of three kinds of components of Pt, CeO ₂ and SnO ₂ . The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 8 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a relatively small current value of 0.3 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.53 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 8 are summarized in Tables 7 to 12.

Comparative Example 9;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 1. wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 0 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. Precipitation was generated, but the concentration of the precipitant solution was too high, so it seems that re-dissolution and re-precipitation of the precipitate occurred, and precipitation was formed, but agglomeration was large, even compared to other examples. The obvious difference was that the precipitate formed was very fast and appeared to have accumulated in the reaction vessel in the aqueous solution.
Subsequently, the solution containing this precipitate was aged at a temperature of 55 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.
The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is 3 of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 4 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a relatively small current value peak of 0.7 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE, and therefore the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was a relatively high value of 0.52 (V vs. RHE), and it was difficult to initiate methanol oxidation.
The results obtained in Comparative Example 9 are summarized in Tables 7 to 12.

Comparative Example 10;
As a starting material, 0.4 (M) of cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 30 ° C. at a rate of 2 ml / min to prepare a precipitate. Subsequently, the solution containing the precipitate was aged at a temperature of 30 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is 3 of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 5 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 1.2 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.48 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 10 are summarized in Tables 7 to 12.

Comparative Example 11;
As a starting material, 0.4 (M) of cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 25 (M) ammonium hydrogen carbonate aqueous solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 70 ° C. at a rate of 2 ml / min to prepare a precipitate. Subsequently, the solution containing this precipitate was aged at a temperature of 70 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is 3 of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 8 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a relatively small current value peak of 1.3 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE, and therefore the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.48 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 11 are summarized in Tables 7 to 12.

Comparative Example 12;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 5 ml / min to prepare a precipitate. Subsequently, the solution containing this precipitate was aged at a temperature of 55 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode material shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode material is 3 of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 7 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a relatively small current value of 1.2 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.49 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 12 are summarized in Tables 7 to 12.

Comparative Example 13;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and an aqueous cerium nitrate solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. Subsequently, the solution containing the precipitate was aged at 55 ° C. for 1 hour after the cerium nitrate aqueous solution was dropped.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode powder shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode powder is composed of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 6 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 1.2 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.48 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 13 are summarized in Tables 7 to 12.

Comparative Example 14;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and an aqueous cerium nitrate solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. Subsequently, the solution containing this precipitate was aged at a temperature of 55 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.
The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 200 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 200 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode powder shows a result different from that shown in FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode powder is Pt, Ce (NO ₃ ) ₃ , Ce. It was found to be composed of a plurality of components of cerium nitrate such as (OH) (NO ₃ ) ₂ and SnO ₂ . The specific surface areas of Ce salt and SnO ₂ measured by the BET method were 15 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 0.3 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.54 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start. The reason is that the pyrolysis of the raw material in the electrode material is not completely completed by evaporating and drying the solvent under an inert gas flow, followed by baking at a temperature of 200 ° C. under a hydrogen flow. , CeO ₂ , SnO as well as cerium nitrates such as Ce (NO ₃ ) ₃ and Ce (OH) (NO ₃ ) ₂ resulted in a significant decrease in electrode reaction. Considered.
The results obtained in Comparative Example 14 are summarized in Tables 7 to 12.

Comparative Example 15;
As a starting material, 0.4 (M) cerium nitrate (purity 99.99%) and 0.03 wt% Pt / 19 wt% (0.77 CeO ₂ 0.33 SnO ₂ ) / 51 wt% C were used. A 25 (M) aqueous ammonium hydrogen carbonate solution (purity 99.5%) was prepared, and an aqueous cerium nitrate solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to prepare a precipitate. Subsequently, the solution containing this precipitate was aged at a temperature of 55 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 550 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (same as in Example 1) ) Was physically mixed and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode powder shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode powder is composed of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 8 and 60 m ² / g, respectively. The particle diameter of Pt in the produced anode material was estimated from the surface area measured by the CO stripping method to be 8.5 m ² / g, and the average secondary particle diameter calculated from the surface area was 33 nm. .
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 0.6 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, was a relatively high value of 0.52 (V vs. RHE), and it was difficult to initiate methanol oxidation. The main reason for this was that the solvent was evaporated and dried under a flow of inert gas and then baked at a temperature of 550 ° C., so that the coarsening of Pt progressed and the activity was significantly reduced.
The results obtained in Comparative Example 15 are summarized in Tables 7 to 12.

Comparative Example 16;
Composition _{30wt% Pt / 19wt% (0.77CeO} 2 0.33SnO 2) / so that 51 wt% C, as a starting material, cerium nitrate 0.4 (M) and (purity 99.99%) 0. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to produce a precipitate. Subsequently, the solution containing this precipitate was aged at a temperature of 55 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.005 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder (sample of Example 1) at room temperature Were calcined at 1000 ° C. for 1 hour in air) and then mixed with a predetermined amount of carbon black powder to obtain an anode material.
The X-ray diffraction pattern of the obtained anode powder shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode powder is composed of Pt, CeO ₂ and SnO ₂ . It was found to be composed of various components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 50 and 8 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.

The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a relatively small current value of 1.1 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. although the addition of the hydrogen and CO takes place, hardly occurs conversion reaction of CO to CO ₂ by-product, was confirmed to exhibit a very low electrode activity. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.48 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start.
The results obtained in Comparative Example 16 are summarized in Tables 7 to 12.

Comparative Example 17;
Composition _{30wt% Pt / 19wt% (0.77CeO} 2 0.33SnO 2) / so that 51 wt% C, as a starting material, cerium nitrate 0.4 (M) and (purity 99.99%) 0. A 25 (M) aqueous ammonium carbonate solution (purity 99.5%) was prepared, and a cerium nitrate aqueous solution was dropped into the aqueous ammonium carbonate solution heated to 55 ° C. at a rate of 2 ml / min to produce a precipitate. Subsequently, the solution containing this precipitate was aged at a temperature of 55 ° C. for 20 hours after the dropwise addition of the cerium nitrate aqueous solution.

The precipitate thus obtained was repeatedly washed with water and filtered three times, and then alternately treated with ethanol and filtered twice, and dried in dry nitrogen gas for two days to produce a precursor powder. . The precursor powder was subsequently calcined at a temperature of 400 ° C. for 2 hours under an oxygen flow to prepare a crystalline ceria powder. Ceria powder was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 0.025 M), after the solvent is evaporated in an inert gas flow under dry, at a temperature of 400 ° C., Under a hydrogen flow, calcined at W / F (sample weight / hydrogen gas flow rate) 0.05 (g · min / ml) for 1 hour, and then a predetermined amount of SnO ₂ powder at room temperature (sample of Example 1) Were the same as the above and then mixed with a predetermined amount of carbon black powder to obtain an anode material.

The X-ray diffraction pattern of the obtained anode powder shows the same result as that of FIG. 1 shown in Example 1. From the identification result of the crystal phase, the anode powder is Pt, CeCl ₄ , CeO ₂ and SnO. It was found that it was composed of ₂ types of 4 components. The specific surface areas of CeO ₂ and SnO ₂ measured by the BET method were 21 and 60 m ² / g, respectively. The Pt particle size in the produced anode material was 28 m ² / g as estimated from the surface area measured by the CO stripping method, and the average secondary particle size calculated from the surface area was 10 nm.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.

As a result, a peak of a relatively small current value of 0.4 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE, and therefore the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. In addition, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.53 (V vs. RHE), which indicates that the oxidation of methanol is difficult to start. In order to consider this reason, as a result of examining the electrode material by an X-ray diffraction test, diffraction lines attributed to cerium chloride were observed, and the intensity of diffraction lines attributed to ceria was significantly reduced. Thus, it was considered that the generation of cerium chloride as a by-product and insufficient reduction of Pt led to a significant decrease in activity.
The results obtained in Comparative Example 17 are summarized in Tables 7 to 12.

Comparative Example 18;
For comparison, an anode material (Johnson Mattey, High SPEC 7000) with a composition of 30 wt% Pt / 15 wt% Ru / 55 wt% C was used, and the anode material was heated at a temperature of 400 ° C. Under hydrogen flow, the Pt surface was activated by calcining at W / F (sample weight / hydrogen gas flow rate) of 0.005 (g · min / ml) for 1 hour.
From the TEM observation result, it was found that the Pt particles on the produced electrode material active material were nanoparticles having a secondary particle diameter of about 3 to 5 nanometers.
The anode material thus obtained was evaluated for electrode activity by cyclic voltammetry under the same experimental conditions as in Example 1.
As a result, a peak of a relatively small current value of 1.75 mA / cm ² indicating methanol oxidation was confirmed at a potential of 0.82 V vs RHE. Therefore, the anode material obtained in this comparative example was obtained from methanol. Although addition to hydrogen and CO occurs, it was confirmed that the conversion reaction of CO, which is a by-product, to CO ₂ hardly occurs and extremely low electrode activity is exhibited. Further, on set potential, which is an index indicating whether or not the oxidation reaction of methanol easily occurs, is a relatively high value of 0.46 (V vs. RHE), which is higher than that of the anode electrode produced according to the present invention. As a result, it was difficult to start oxidation.

  Summarizing the above examples and comparative examples, the anode material is defined by the composition formula based on the general formula defined in the claims of the present invention, and the average particle diameter and specific surface area of the anode material are specified respectively. It was clarified that the electrode activity was extremely high compared to the range outside the range. In other words, according to this data, it can be said that each requirement defined in the scope of claims defines a matter of exceptional significance.

  In recent years, reduction of carbon dioxide has been called out as part of global warming countermeasures, while development of high-power small fuel cells has been actively promoted to meet increasing energy demand. For the development of such fuel cells, it is essential to research and develop solid electrolytes for fuel cells that exhibit high output in a temperature range that can be easily applied at home. The present invention provides a fuel cell electrode material that exactly meets this need, and is expected to be used greatly in the future. The high-performance electrode of the present invention is extremely stable because it has been successfully developed based on new knowledge at the nano-level heterointerface based on a very diverse and basic viewpoint. In the future, it is expected to be used as an excellent electrode material not only in fuel cells but also in various technical fields. In particular, since it is an electrode with excellent recyclability, such as platinum, its range of use is wide, and it is expected to develop into the creation of new industries.

Pt / CeO ₂ .SnO ₂ / conductive carbon-based nanoheteroanode material (a: anode material of Example 1) synthesized according to the present invention, Pt / CeO ₂ / conductive carbon-based nanoheteroanode material (b ) And a commercially available Pt / Ru / conductive carbon-based nanoheteroanode material (c: anode material of Comparative Example 20). Pt / CeO ₂ .SnO ₂ / conductive carbon-based nanoheteroanode material (a: anode material of Example 1) synthesized on the basis of the present invention and commercially available Pt / Ru / conductive carbon-based nanoheteroanode material ( b: Comparison of cyclic voltammograms of the anode material of Comparative Example 20). (Electrolyte: 0.5 M sulfuric acid aqueous solution + 0.5 M methanol, scanning speed: 50 mV / sec) Pt / CeO ₂ .SnO ₂ / conductive carbon-based nanoheteroanode material (a: anode material of Example 1) synthesized on the basis of the present invention and a commercially available Pt / Ru / conductive carbon-based nanoheteroanode material ( b: Comparison of on set potential of methanol oxidation reaction on anode material of comparative example 20).

Claims (3)

An anode material having an oxidation activity, which does not dissolve components such as conductive carbon and rare earth elements, and has a specific surface area of 1 × 10 m ² / g or more and 1 × 10 ² m ² / g or less. and ₂ powder, the specific surface area and is 1 × ^{10 m} 2 / g or more 1 × ¹⁰ 2 ^m 2 / g or less of SnO ₂ powder, with an average secondary particle diameter is a mixture of 30 nanometers or less of Pt, formula 1 It is characterized by satisfying.
(Chemical formula 1)
XPt / Y (ACeO _2. (1-A) SnO ₂ ) / Zcarbon
(In the formula, X, Y, Z, and A represent the content ratios of platinum (Pt), CeO ₂ , SnO ₂ , and carbon, respectively, and 5 × 10 ⁻² ≦ X ≦ 4 × 10 ⁻¹ 1. × 10 ⁻¹ ≦ Y ≦ 3 × 10 ⁻¹ , Z = 1−XY, 6 × 10 ⁻¹ ≦ A <8 × 10 ⁻¹ , and Carbon represents conductive carbon) A method for producing an anode material according to claim 1, characterized by the following steps.
Concentration 5 × ^{10 -2} mol / liter (hereinafter (M) and denoted) or 8 × ¹⁰ -1 cerium nitrate aqueous solution (M) or less, the concentration 1 × ^{10 -1} which is at a temperature of 45 ° C. or higher 60 ° C. or less ( M) a first step of preparing a ceria precursor by dropping into an aqueous ammonium carbonate or ammonium hydrogen carbonate solution of 5 × 10 ⁻¹ (M) or less at a rate of 2.5 ml / min or less;
The ceria precursor obtained in the first step is maintained at that temperature for 2 × 10 hours or more and less than 4 × 10 hours, and is subjected to solid-liquid separation, washed with water and dried to obtain the solid content,
A third step of preparing a calcined to crystalline ceria powder is less than 3 × 10 ² ° C. Ultra 5 × 10 ² ° C. The solid obtained in an oxygen stream atmosphere in the second step,
The ceria powder obtained in the third step was mixed with chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) aqueous solution (concentration 1 × 10 ^-2 (M) or 5 × 10 ^-2 (M) hereinafter), the solvent A fourth step of evaporating and drying in an inert gas flow;
A fourth solids obtained in Step 3 × 10 ² ℃ super 5 × 10 below ² ℃ temperature, under a hydrogen stream atmosphere, W / F (sample weight / hydrogen gas flow) 1 × ^{10 -3} ( g · min / ml) to 1 × 10 ⁻² (g · min / ml),
A sixth step in which SnO ₂ powder is physically mixed with the powder obtained in the fifth step and then mixed with conductive carbon.   A fuel cell comprising the anode material according to claim 1 as an anode electrode.