JP2023058874A - Catalyst for inverse water gas shift reaction, and production method of carbon monoxide using the same - Google Patents

Abstract

To provide a catalyst for inverse water gas shift reaction excellent in catalytic activity and having high reactivity even under a reaction condition of low temperature and a production method of carbon monoxide using the same.SOLUTION: A catalyst for inverse water gas shift reaction is used to produce carbon monoxide from carbon dioxide and hydrogen. The catalyst for inverse water gas shift reaction includes a metal oxide carrier, a complex oxide carried by the metal oxide carrier, and a metal catalyst. The complex oxide contains an oxide of at least one metal element selected from the group consisting of the group 4 elements, the group 5 elements, and the group 6 elements of the periodic table as a first metal oxide and an oxide of at least one metal element selected from the group consisting of the group 1 elements and the group 2 elements of the periodic table as a second metal oxide.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a reverse water gas shift reaction catalyst and a method for producing carbon monoxide using the same.

In recent years, with the aim of creating a sustainable low-carbon society based on green and sustainable chemistry, research has been conducted on conversion of carbon dioxide (CO ₂ ) into core chemicals by reducing it with hydrogen (H ₂ ), a renewable energy source. is being done. For example, carbon monoxide (CO), which is obtained by reducing _CO2 with _H2 , is a useful chemical feedstock as a carbonyl feedstock in organic synthesis and as a feedstock for liquid hydrocarbons such as alcohol, jet fuel, and gasoline.

As a method for reducing CO ₂ with H ₂ , the reverse water gas shift reaction represented by the following formula (1) is known.
_CO2 + _H2- >CO+ _H2O (1)

The reverse water gas shift reaction is an equilibrium reaction, an endothermic reaction favoring high temperatures. As the reverse water gas shift reaction catalyst, for example, an alkaline earth metal carbonate composed of Ca, Sr, or Ba, and a composite of Ca, Sr, or Ba and Ti, Al, Zr, Fe, W, or Mo A catalyst containing an oxide has been reported (see Patent Document 1).

JP 2010-194534 A

However, since the catalyst of Patent Document 1 does not have sufficient catalytic activity, it is necessary to raise the reaction temperature of the reverse water gas shift reaction to a high temperature of 700° C. or higher, and energy saving has been desired. In addition, since a high reaction temperature is required, materials with high heat resistance and special production facilities such as multi-stage heat exchangers are required, leading to the problem of an increase in CO production costs. Furthermore, there is a problem that exposing the catalyst to high temperature conditions for a long time promotes deterioration of the catalyst, leading to a further increase in production costs.
On the other hand, under low-temperature reaction conditions, reactivity is low due to equilibrium constraints, and it has been difficult to efficiently produce CO by the reverse water gas shift reaction.

An object of the present invention is to provide a reverse water gas shift reaction catalyst that is highly reactive even under low-temperature reaction conditions and has excellent catalytic activity, and a method for producing carbon monoxide using the same. .

As a result of intensive research conducted by the inventors to solve the above problems, the inventors have discovered a metal oxide support, a composite oxide containing an oxide of a specific metal element supported on the metal oxide support, and a metal catalyst. The inventors have found that the above problems can be solved by using a catalyst having the above, and have completed the present invention.

That is, the present invention includes the following aspects.
[1] A reverse water-gas shift reaction catalyst used for producing carbon monoxide from carbon dioxide and hydrogen, wherein the reverse water-gas shift reaction catalyst comprises a metal oxide support and supported on the metal oxide support. comprising a composite oxide and a metal catalyst,
The composite oxide includes, as a first metal oxide, an oxide of at least one metal element selected from the group consisting of Group 4 elements, Group 5 elements, and Group 6 elements;
an oxide of at least one metal element selected from the group consisting of Group 1 elements and Group 2 elements as the second metal oxide;
A catalyst for the reverse water gas shift reaction, comprising:
[2] The reverse water gas shift reaction catalyst according to [1], wherein the metal oxide support is _TiO2 .
[3] The reverse water gas shift reaction catalyst according to [1] or [2], wherein the metal catalyst is Pt.
[4] Any one of [1] to [3], wherein the first metal oxide is an oxide of at least one metal element selected from the group consisting of Mo, V, Nb, and W. A catalyst for the reverse water gas shift reaction as described.
[5] Any one of [1] to [4], wherein the second metal oxide is an oxide of at least one metal element selected from the group consisting of Rb, Cs, Ca, Sr, and Ba. The catalyst for the reverse water gas shift reaction according to 1.
[6] The reverse water gas shift reaction catalyst according to any one of [1] to [5], wherein the first metal oxide is a Mo oxide.
[7] The reverse water gas shift reaction according to [6], wherein the content of the Mo oxide is 0.2 to 3.0% by mass as the Mo metal element based on the total amount of the reverse water gas shift reaction catalyst. catalyst for
[8] The reverse water gas shift reaction catalyst according to any one of [1] to [7], wherein the composite oxide further contains a lanthanide oxide as the third metal oxide.
[9] The third metal oxide is an oxide of at least one metal element selected from the group consisting of La, Ce, Pr, Nd, Eu, Gd, Dy, Er, and Lu, [ 8].
[10] A reverse water gas shift reaction, wherein a raw material gas containing carbon dioxide and hydrogen is brought into contact with the reverse water gas shift reaction catalyst according to any one of [1] to [9] to obtain a product gas containing carbon monoxide. Equipped with a process,
A method for producing carbon monoxide.
[11] The method for producing carbon monoxide according to [10], wherein the reaction temperature in the reverse water gas shift reaction step is 100 to 400°C.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a reverse water gas shift reaction catalyst having high reactivity and excellent catalytic activity even under low-temperature reaction conditions, and a method for producing carbon monoxide using the same. .

The present invention will be described in detail below. It should be noted that the description of the constituent elements described below is an example for describing the present invention, and the present invention is not limited to these contents.

(Catalyst for reverse water gas shift reaction)
The reverse water gas shift reaction catalyst according to the present embodiment is used for producing CO from CO ₂ and H ₂ and comprises a metal oxide support, a composite oxide supported on the metal oxide support, and a metal catalyst.

Although the mechanism of action of the reverse water gas shift reaction catalyst according to the present embodiment has not been fully elucidated, an example of a presumed mechanism of action is shown below.
In the reverse water gas shift reaction catalyst according to the present embodiment, a metal oxide support supports a composite oxide containing, for example, molybdenum oxide, and a metal catalyst is supported on the metal oxide support and/or the composite oxide. there is The reason why the reverse water gas shift reaction catalyst according to the present embodiment has excellent reactivity even under low-temperature reaction conditions is that the oxygen deficiency of the oxides constituting the composite oxide facilitates the adsorption and activation of _CO2 . It is presumed that this is due to the cooperative catalytic action of the composite oxide and the metal catalyst, in which the metal catalyst is responsible for the dissociation of H ₂ . Moreover, since the metal oxide carrier that supports the composite oxide and/or the metal catalyst has a porous structure, it has a large specific surface area and many reactive sites. For this reason, the reverse water gas shift reaction catalyst according to the present embodiment is presumed to have high reactivity in the reverse water gas shift reaction even under low-temperature reaction conditions.

<Metal oxide support>
The metal oxide carrier mainly plays a role of supporting a composite oxide and/or a metal catalyst having catalytic activity.

The metal oxide support of the present embodiment has a porous structure from the viewpoint of promoting the reverse water gas shift reaction. Incidentally, a catalyst having no carrier as in Patent Document 1 is usually formed at a calcination temperature of 1000° C. or higher. In this case, the catalyst cannot form a porous structure and tends to have poor reactivity in the reverse water gas shift reaction. On the other hand, the catalyst for reverse water gas shift reaction of the present embodiment is provided with a metal oxide support having a porous structure, so that it has a large specific surface area, many reaction active sites, and excellent catalytic activity.

_The metal oxide support _is not limited as long as _it can form a porous _structure . SiO ₂ ) and the like. Among these, TiO ₂ is preferable from the viewpoint of promoting the reverse water gas shift reaction.

The reverse water gas shift reaction catalyst may be a powder, while the metal oxide support is preferably a spherical or cylindrical molded body from the viewpoint of densely filling the reaction system.

The particle size of the primary particles of the metal oxide support is preferably 10 nm or more, more preferably 50 nm or more. In addition, the particle size is preferably 1000 nm or less, more preferably 800 nm or less. If the particle size is 10 nm or more, the CO production efficiency can be increased without deteriorating the contact efficiency in the reaction system. Moreover, when the particle size is 1000 nm or less, a sufficient specific surface area tends to be obtained, and the reverse water gas shift reaction tends to be promoted more. The particle size of the primary particles of the particles can be determined by an X-ray diffraction method.

The specific surface area of the particles as the metal oxide support is preferably 10 m ² /g or more, more preferably 20 m ² /g or more, and even more preferably 30 m ² /g or more, from the viewpoint of improving the reactivity of the reverse water gas shift reaction. . On the other hand, the specific surface area is preferably 1,000 m ² /g or less, more preferably 500 m ² /g or less, and even more preferably 400 m ² /g or less, from the viewpoint of maintaining catalyst strength.
The specific surface area of particles as metal oxide supports can be determined by the Brunauer-Emmett-Teller (BET) one-point method.

<Composite oxide>
A composite oxide is supported on a metal oxide support. The composite oxide has both a function as a carrier that supports a metal catalyst, which will be described later, and a function as a catalyst that promotes the reverse water gas shift reaction. In addition, the composite oxide has a function of improving the mechanical strength of the reverse water gas shift reaction catalyst.

Composite oxides are considered to have oxygen deficiencies due to reduction treatment. Sites with oxygen vacancies can function as active sites for reactions that abstract oxygen atoms from _CO2 and produce CO. Therefore, the composite oxide according to the present embodiment has both a function as a carrier that supports a metal catalyst, which will be described later, and a function as a catalyst that promotes the reverse water gas shift reaction.

The composite oxide comprises, as a first metal oxide, an oxide of at least one metal element selected from the group consisting of Group 4 elements, Group 5 elements, and Group 6 elements, and a second metal The oxides include oxides of at least one metal element selected from the group consisting of Group 1 elements and Group 2 elements.
By combining the first metal oxide and the second metal oxide, the reactivity of the reverse water gas shift reaction can be further improved.

<<First Metal Oxide>>
The first metal oxide is a metal element belonging to Group 4 elements, Group 5 elements, or Group 6 elements in the periodic table of long period elements based on the regulations of IUPAC (International Union of Pure and Applied Chemistry) is not particularly limited as long as it is an oxide of Specifically, as the first metal oxide, titanium (Ti), zirconium (Zr), hafnium (Hf), rutherfordium (Rf), vanadium (V), niobium (Nb), tantalum (Ta), dubnium (Db), chromium (Cr), molybdenum (Mo), tungsten (W), or seaborgium (Sg) oxides can be used. One kind of the first metal oxide may be used alone, or two or more kinds thereof may be used.

Among the above, from the viewpoint of excellent reactivity in the reverse water gas shift reaction, the first metal oxide is an oxide of at least one metal element selected from the group consisting of V, Nb, Mo, and W. and particularly preferably an oxide of Mo.

Mo is known to have at least eight oxidation numbers of 6, 5, 4, 3, 2, 1, -1 and -2. At least two molybdenum oxides, which are Mo oxides, are known, for example, molybdenum (IV) oxide (MoO ₂ ) and molybdenum (VI) oxide (MoO ₃ ). Among these molybdenum oxides, molybdenum (VI) oxide (MoO ₃ ) is more preferable from the viewpoint of excellent reactivity in the reverse water gas shift reaction due to moderate reduction treatment. However, it is thought that molybdenum oxide can assume different oxidation states through reduction reactions and reverse shift reactions.

<<second metal oxide>>
The second metal oxide is an oxide of a metal element belonging to Group 1 elements or Group 2 elements in the periodic table of long period elements based on the IUPAC (International Union of Pure and Applied Chemistry) regulations. is not particularly limited. Specifically, as the second metal oxide, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), or radium (Ra) oxides can be used. The second metal oxide may be used alone or in combination of two or more.

Among the above, from the viewpoint of excellent reactivity in the reverse water gas shift reaction, the second metal oxide is at least one metal element selected from the group consisting of Rb, Cs, Ca, Sr, and Ba. It is preferably an oxide.

<<Third Metal Oxide>>
The composite oxide may optionally further contain a third metal oxide. As the third metal oxide, the group consisting of Group 3 elements, Group 14 elements, and Group 15 elements in the periodic table of long period elements based on the regulations of IUPAC (International Union of Pure and Applied Chemistry) An oxide of at least one more selected metal element is preferred, and a lanthanide oxide is more preferred. Lanthanide means any metallic element with atomic numbers 57-71, including atomic numbers 57 and 71. The third metal oxide may be used alone or in combination of two or more.

Among the lanthanoids, from the viewpoint of excellent reactivity in the reverse water gas shift reaction, the third metal element includes lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), europium (Eu), It is preferably an oxide of at least one metal element selected from the group consisting of gadolinium (Gd), dysprosium (Dy), erbium (Er), and lutetium (Lu).

Further, as the third metal oxide, in addition to the lanthanide oxides described above, scandium (Sc) oxides belonging to Group 3 elements of the periodic table, oxidation of tin (Sn) belonging to Group 14 elements of the periodic table , or an oxide of bismuth (Bi) belonging to Group 15 of the periodic table can also be used satisfactorily.

From the viewpoint of excellent reactivity in the reverse water-gas shift reaction, the content of the metal oxide in the composite oxide is preferably 0.5% by mass or more, and preferably 0.7, as a metal element based on the total amount of the catalyst for the reverse water-gas shift reaction. % by mass or more is more preferable, and 1.0% by mass or more is even more preferable. On the other hand, from the viewpoint of the balance between oxygen abstraction and hydrogenation, the content is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 7% by mass or less, based on the total amount of the reverse water gas shift reaction catalyst. . In addition, the content of the metal oxide in the composite oxide is the content of two or more metal elements, including the first metal oxide, the second metal oxide, and the optional third metal oxide. It is the total amount.

When the first metal oxide contains molybdenum oxide (MoO ₃ ), which is an oxide of Mo, the content of the Mo metal element should be determined from the viewpoint of excellent reactivity in the reverse water-gas shift reaction. Based on the total amount, it is preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more. On the other hand, from the economical point of view of the process, the content is preferably 3.0% by mass or less, more preferably 2.0% by mass or less, and 1.0% by mass or less, based on the total amount of the catalyst for the reverse water gas shift reaction. More preferred.
The content of Mo in conventional catalysts is usually 10% by mass or more based on the total amount of the catalyst. The present inventors have found for the first time that a catalyst containing molybdenum oxide within the above range as a composite oxide exhibits excellent reactivity in the reverse water gas shift reaction.

The composite oxide may be used as a metal oxide as described above, and may be oxidized after being supported as a metal on a support, or may be directly supported on a support as a metal oxide.

<Metal catalyst>
A metal catalyst is carried on a metal oxide carrier and/or a composite oxide. The metal catalyst functions as a catalyst that promotes the reverse water gas shift reaction.

The metal catalyst is not particularly limited as long as it promotes the reverse water gas shift reaction. It is preferably a metal element belonging to Group 9 elements or Group 10 elements. Among these, the metal catalyst is preferably nickel (Ni), iron (Fe), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), or platinum (Pt), and particularly Pt. preferable. The metal catalyst may be used singly or in combination of two or more.

The content of the metal catalyst is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, based on the total amount of the reverse water gas shift reaction catalyst, from the viewpoint of excellent reactivity in the reverse water gas shift reaction. On the other hand, the content is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, based on the total amount of the reverse water gas shift reaction catalyst, from an economical point of view.

<Other ingredients>
From the viewpoint of improving moldability, the reverse water gas shift reaction catalyst may optionally contain other components such as molding aids as long as the object of the present invention is not impaired. The molding aid may be, for example, at least one selected from the group consisting of thickeners, surfactants, water retention agents, plasticizers, binder raw materials, and the like. In addition, the reverse water gas shift reaction catalyst may contain other useful components as long as they do not impair the object of the present invention.

(Method for preparing catalyst for reverse water gas shift reaction)
The reverse water gas shift reaction catalyst is not particularly limited and can be prepared by a conventionally known method.
For example, a step of mixing an aqueous solution of a metal oxide support and a composite oxide precursor, removing the solvent, and then calcining the remaining solid containing the metal oxide support and the composite oxide; After contacting with an aqueous solution of the precursor and removing the solvent, the catalyst for the reverse water gas shift reaction is prepared by a method including a step of calcining the remaining solids containing the metal oxide support, the composite oxide and the metal catalyst. Obtainable.

The firing temperature for firing the solid is not particularly limited, but is preferably 300 to 600°C. When the calcination temperature is 300° C. or higher, thermal stability that can withstand long-term use is likely to be obtained, and a catalyst with high catalytic activity tends to be obtained. Further, when the firing temperature is 600° C. or lower, the metal oxide support tends to easily form a porous structure. The firing time is not particularly limited, but is preferably 0.1 to 24 hours.

The reverse water gas shift reaction catalyst is generally preferably subjected to a reduction treatment before being used as a reaction catalyst. The method of reduction treatment is not particularly limited. For example, reduction treatment can be performed by a method of heating the reverse water gas shift reaction catalyst in an atmosphere containing hydrogen gas. A heating temperature for the reduction treatment is, for example, 150 to 450.degree. The reduction treatment time is, for example, 0.1 to 5 hours.

(Method for producing carbon monoxide)
In the method for producing carbon monoxide according to the present embodiment, as shown in the following formula (2), a raw material gas containing CO ₂ and H ₂ is brought into contact with the reverse water gas shift reaction catalyst according to the present embodiment described above. and a reverse water gas shift reaction step to obtain a product gas containing CO.
_CO2 + _H2- >CO+ _H2O (2)

<Raw material gas>
The raw material gas may contain at least CO ₂ and H ₂ . The production origin of CO ₂ and H ₂ is not particularly limited. For example, CO ₂ may be used as it is in a process of burning hydrocarbons as fuel or a process of burning unreacted hydrocarbons in petroleum refining, petrochemicals, power generation, iron manufacturing, boilers, etc. and purified ones may be used. Alternatively, CO ₂ in the atmosphere may be concentrated and used.

The volume ratio (H ₂ /CO ₂ ) of CO ₂ and H ₂ in the source gas is not particularly limited, but is preferably 7:1 to 1:2, more preferably 5:1 to 1:1. The higher the H ₂ /CO ₂ ratio in the raw material gas, the more easily the reverse water gas shift reaction proceeds, but if it is too high, the methanation reaction, which is a side reaction, tends to occur more easily.

The source gas may further contain compounds other than CO ₂ and H ₂ as long as they do not inhibit the reverse water gas shift reaction. For example, it may further contain an inert gas such as nitrogen or argon.

<Reverse water gas shift reaction step>
In the reverse water-gas shift reaction step, for example, the reaction may be carried out by using a reactor filled with a reverse water-gas shift reaction catalyst and passing the raw material gas through the reactor. As the reactor, various reactors used for gas phase reactions using solid catalysts can be used. Examples of reactors include fixed bed reactors, radial flow reactors, tubular reactors, and the like.

The temperature at which the raw material gas is brought into contact with the catalyst for the reverse water-gas shift reaction (which can also be called the reaction temperature of the reverse water-gas shift reaction or the temperature inside the reactor) is 400°C from the viewpoint of energy saving and production cost. below is preferable, and 300° C. or less is more preferable. Since the reverse water gas shift reaction catalyst according to the present embodiment has excellent catalytic activity as described above, CO can be efficiently produced even at a low temperature of 400° C. or less. On the other hand, the temperature is preferably 100° C. or higher, more preferably 150° C. or higher, from the viewpoint of further improving the yield and production rate of CO.

The pressure when the raw material gas is brought into contact with the catalyst for the reverse water-gas shift reaction (reaction pressure of the reverse water-gas shift reaction, or the pressure inside the reactor) is not particularly limited, but is, for example, 0 to 4.0 MPaG. can be

When the reverse water gas shift reaction step is performed in a continuous reaction format in which raw materials are continuously supplied, the gas hourly space velocity (hereinafter sometimes referred to as "GHSV") is preferably 10 h ^-1 or more, and 100 h ^{- 1} or more is more preferable. If the GHSV is 10 h ⁻¹ or more, the reactor size can be made smaller. On the other hand, GHSV is preferably 100,000 h ^-1 or less, more preferably 50,000 h ^-1 or less. If the GHSV is 100,000 h ⁻¹ or less, the CO yield tends to be higher. Here, GHSV is the ratio (F/V) of the supply rate (supply amount/time) F of the raw material gas to the capacity V of the catalyst for reverse water gas shift reaction in a continuous reactor. The amounts of the raw material gas and the catalyst used may be appropriately selected in a more preferable range according to the reaction conditions, the activity of the catalyst, etc., and the GHSV is not limited to the above range.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the scope of the present invention is not limited to these Examples.

<Example 1>
(Preparation of catalyst for reverse water gas shift reaction)
Pentakis (hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemical) 3.67 mg as a complex oxide precursor, hexaammonium heptamolybdate tetrahydrate (Fujifilm Wako Pure Chemical Industries) 4 42 mg, barium nitrate (Kanto Kagaku) 2.28 mg, titanium oxide (P-25, Nippon Aerosil) 286.6 mg as a metal oxide carrier, and water 100 mL were stirred at room temperature for 30 minutes. The solvent was distilled off under reduced pressure while the mixture was heated to 50°C, and the residue was dried at 110°C for 1 hour. The dried solids were ground with an agate mortar and pestle. The obtained powder was calcined at 500° C. for 3 hours in an air atmosphere to obtain particles containing titanium oxide and niobium oxide, molybdenum oxide, and barium oxide supported thereon. A mixture of 150 mg of the obtained particles, 0.1 g of dinitrodiammineplatinum (II) nitric acid solution (Furuya Metals, 4.60 wt % as Pt purity) as a metal catalyst precursor, and 20 mL of water was stirred at room temperature for 30 minutes. The solvent was distilled off under reduced pressure while the mixture was heated to 50°C, and the residue was dried at 110°C for 1 hour. The dried solid was ground with an agate mortar and pestle to obtain titanium oxide, niobium oxide supported thereon (0.2% by mass as Nb), molybdenum oxide (0.8% by mass as Mo), and barium oxide. (0.4% by mass as Ba) and platinum (3.0% by mass as Pt), the reverse water gas shift reaction catalyst of Example 1 was obtained.

(Production of carbon monoxide)
10 mg of the catalyst for reverse water gas shift reaction was subjected to reduction treatment under normal pressure at 300° C. for 0.5 hour under a hydrogen stream of 40 mL/min. The fixed-bed reactor was filled with the reduced reverse water-gas shift reaction catalyst. After that, 60 mL/min of hydrogen, 20 mL/min of carbon dioxide, and 5 mL/min of nitrogen were introduced into the fixed bed reactor at normal pressure. The reaction was carried out at 250°C.

After 40 hours from the start of the reaction, product gas was sampled from the fixed bed reactor. Note that the reaction start time is the time when the supply of the raw material gas is started. The sampled product gas was analyzed using a gas chromatograph (TCD-GC) equipped with a thermal conductivity detector. Based on the gas chromatograph, each component of the sampled produced gas was quantified, and the yield of carbon monoxide was calculated. Also, the reaction rate of carbon monoxide per amount of catalyst was calculated. Table 1 shows the results.

The reaction rate of carbon monoxide per amount of catalyst was determined as follows.
The CO ₂ supply rate was calculated from the CO ₂ concentration and the flow rate, and the CO production rate (mmol/min) was obtained by multiplying the CO ₂ supply rate by the CO yield. Further, the CO production rate per catalyst amount (mmol/min/gcat) was calculated by dividing the CO production rate by the reverse water gas shift reaction catalyst amount (g).

<Example 2>
Instead of the composite oxide precursor of Example 1, 3.67 mg of pentakis(hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemicals), hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 4.42 mg, rubidium carbonate (Fuji Film Wako Pure Chemical Industries) 0.81 mg, and lutetium nitrate (Fuji Film Wako Pure Chemical Industries) 1.24 mg. Thus, a reverse water gas shift reaction catalyst of Example 2 was obtained. The reverse water gas shift reaction catalyst of Example 2 includes titanium oxide, niobium oxide supported thereon (0.2% by mass as Nb), molybdenum oxide (0.8% by mass as Mo), and rubidium oxide (0.8% by mass as Rb). .2 mass %), lutetium oxide (0.2 mass % as Lu), and platinum (3.0 mass % as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 3>
Instead of the composite oxide precursor of Example 1, 18.34 mg of pentakis(hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemicals), hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 5.52 mg, rubidium carbonate (Fuji Film Wako Pure Chemical Industries) 4.05 mg, and gadolinium nitrate (Fuji Film Wako Pure Chemical Industries) 17.22 mg. Thus, a reverse water gas shift reaction catalyst of Example 3 was obtained. The reverse water gas shift reaction catalyst of Example 3 includes titanium oxide, niobium oxide supported thereon (1.0% by mass as Nb), molybdenum oxide (1.0% by mass as Mo), rubidium oxide (1.0% by mass as Rb). .0 mass %), gadolinium oxide (2.0 mass % as Gd), and platinum (3.0 mass % as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 4>
4.42 mg of hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries), 3.43 mg of barium nitrate (Kanto Kagaku), and erbium nitrate n-hydrate instead of the composite oxide precursor of Example 1 (Fuji Film Wako Pure Chemical Industries) 1.27 mg and 4.18 mg of bismuth nitrate pentahydrate (Fuji Film Wako Pure Chemical Industries) were used. A catalyst for gas shift reaction was obtained. The reverse water gas shift reaction catalyst of Example 4 includes titanium oxide, molybdenum oxide supported thereon (0.8% by mass as Mo), barium oxide (0.6% by mass as Ba), erbium oxide (0% as Er). .2% by weight), bismuth oxide (0.6% by weight as Bi), and platinum (3.0% by weight as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 5>
Instead of the composite oxide precursor of Example 1, 4.42 mg of hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries), 2.28 mg of barium nitrate (Kanto Chemical), tin (II) chloride ( Anhydrous) (Fuji Film Wako Pure Chemical Industries, Ltd.) 2.88 mg was used, but a reverse water-gas shift reaction catalyst of Example 5 was obtained in the same manner as in Example 1. The catalyst for the reverse water gas shift reaction of Example 5 includes titanium oxide, molybdenum oxide supported thereon (0.8% by mass as Mo), barium oxide (0.4% by mass as Ba), tin oxide (0 .6% by mass), and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 6>
Instead of the composite oxide precursor of Example 1, 3.44 mg of ammonium vanadate (V) (Fujifilm Wako Pure Chemical Industries), pentakis (hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa chemicals) 18.34 mg, hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 2.76 mg, strontium nitrate (Kanto Chemical) 7.25 mg, barium nitrate (Kanto Chemical) 4.57 mg A reverse water gas shift reaction catalyst of Example 6 was obtained in the same manner as in Example 1 except for the above. The reverse water gas shift reaction catalyst of Example 6 includes titanium oxide, vanadium oxide supported thereon (0.5% by mass as V), niobium oxide (1.0% by mass as Nb), molybdenum oxide (0% as Mo .5% by mass), strontium oxide (1.0% by mass as Sr), barium oxide (0.8% by mass as Ba), and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 7>
Instead of the composite oxide precursor of Example 1, 3.67 mg of pentakis(hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemicals), hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 3.31 mg, ammonium tungstate para pentahydrate (Fuji Film Wako Pure Chemical Industries) 0.43 mg, cesium nitrate (Kanto Chemical) 0.44 mg, scandium acetate (III) hydrate (Tokyo Kasei Kogyo Co., Ltd.) 2.96 mg was used, but a reverse water gas shift reaction catalyst of Example 7 was obtained in the same manner as in Example 1. The reverse water gas shift reaction catalyst of Example 7 includes titanium oxide, niobium oxide supported thereon (0.2% by mass as Nb), molybdenum oxide (0.6% by mass as Mo), tungsten oxide (0 as W .1 mass %), cesium oxide (0.1 mass % as Cs), scandium oxide (0.2 mass % as Sc), and platinum (3.0 mass % as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 8>
Instead of the composite oxide precursor of Example 1, 8.28 mg of hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries), 3.62 mg of strontium nitrate (Kanto Chemical), lanthanum (III) nitrate hexa Hydrate (Fuji Film Wako Pure Chemical Industries) 18.70 mg, europium nitrate hexahydrate (Alfa Aesar) 4.40 mg, lutetium nitrate (Fuji Film Wako Pure Chemical Industries) 6.19 mg, except for using Examples A reverse water gas shift reaction catalyst of Example 8 was obtained by the same procedure as in Example 1. The catalyst for the reverse water gas shift reaction of Example 8 includes titanium oxide, molybdenum oxide supported thereon (1.5% by mass as Mo), strontium oxide (0.5% by mass as Sr), lanthanum oxide (2 as La .0% by mass), europium oxide (0.5% by mass as Eu), lutetium oxide (1.0% by mass as Lu), and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 9>
Instead of the composite oxide precursor of Example 1, 3.44 mg of ammonium vanadate (V) (Fujifilm Wako Pure Chemical Industries), pentakis (hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa chemicals) 18.34 mg, hexaammonium heptamolybdate tetrahydrate (Fujifilm Wako Pure Chemical Industries) 2.76 mg, calcium nitrate tetrahydrate (Fujifilm Wako Pure Chemical Industries) 8.84 mg, lanthanum nitrate (III ) A reverse water gas shift reaction catalyst of Example 9 was obtained in the same manner as in Example 1, except that 4.68 mg of hexahydrate (Fuji Film Wako Pure Chemical Industries) was used. The reverse water gas shift reaction catalyst of Example 9 includes titanium oxide, vanadium oxide supported thereon (0.5% by mass as V), niobium oxide (1.0% by mass as Nb), molybdenum oxide (0% as Mo .5% by mass), calcium oxide (0.5% by mass as Ca), lanthanum oxide (0.5% by mass as La), and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 10>
Instead of the composite oxide precursor of Example 1, 18.34 mg of pentakis(hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemicals), hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 2.76 mg, Strontium Nitrate (Kanto Chemical) 3.62 mg, Cerium (III) Nitrate Hexahydrate (Fuji Film Wako Pure Chemical Industries) 13.95 mg, Dysprosium Nitrate Hexahydrate (Fuji Film) Wako Pure Chemical Industries) 16.86 mg was used, but a reverse water gas shift reaction catalyst of Example 10 was obtained in the same manner as in Example 1. The reverse water gas shift reaction catalyst of Example 10 includes titanium oxide, niobium oxide supported thereon (1.0% by mass as Nb), molybdenum oxide (0.5% by mass as Mo), strontium oxide (0 as Sr .5 mass %), cerium oxide (1.5 mass % as Ce), dysprosium oxide (2.0 mass % as Dy), and platinum (3.0 mass % as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 11>
Instead of the composite oxide precursor of Example 1, 3.67 mg of pentakis(hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemicals), hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 3.31 mg, cesium nitrate (Kanto Chemical) 6.16 mg, and barium nitrate (Kanto Chemical) 5.71 mg. A catalyst for gas shift reaction was obtained. The reverse water gas shift reaction catalyst of Example 11 comprises titanium oxide, niobium oxide supported thereon (0.2% by mass as Nb), molybdenum oxide (0.6% by mass as Mo), cesium oxide (1% as Cs .4 mass %), barium oxide (1.0 mass % as Ba), and platinum (3.0 mass % as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Example 12>
Instead of the composite oxide precursor of Example 1, 3.67 mg of pentakis(hydrogen oxalate) niobium (V) (n-hydrate) (Mitsuwa Chemicals), hexaammonium heptamolybdate tetrahydrate (Fuji Film Wako Pure Chemical Industries) 3.31 mg, rubidium carbonate (Fuji Film Wako Pure Chemical Industries) 4.05 mg, and barium nitrate (Kanto Chemical) 5.71 mg were used. Twelve reverse water gas shift catalysts were obtained. The reverse water gas shift reaction catalyst of Example 12 includes titanium oxide, niobium oxide supported thereon (0.2% by mass as Nb), molybdenum oxide (0.6% by mass as Mo), rubidium oxide (1% as Rb .0% by mass), barium oxide (1.0% by mass as Ba), and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Comparative Example 1>
Comparative Example No. 1 catalyst for reverse water gas shift reaction was obtained. The reverse water gas shift reaction catalyst of Comparative Example 1 comprises titanium oxide, molybdenum oxide (5.0% by mass as Mo) supported thereon, and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

<Comparative Example 2>
Comparative Example No. 2 reverse water gas shift reaction catalyst was obtained. The reverse water gas shift reaction catalyst of Comparative Example 2 comprises titanium oxide, molybdenum oxide (0.1% by mass as Mo) supported thereon, and platinum (3.0% by mass as Pt).
The yield of carbon monoxide and the reaction rate of carbon monoxide per amount of catalyst for reverse water gas shift reaction were calculated in the same manner as in Example 1. Table 1 shows the results.

As shown in Table 1, as a result of using the catalysts of Examples 1 to 12 according to the present embodiment at a reaction temperature of 250° C., only CO was produced without detecting methane as a by-product. The CO production rates in Examples 1 to 12 are all 2.5 mmol/min/gcat or more, indicating that the catalysts of Examples 1 to 12 have high catalytic activity. Also, the catalysts of Examples 1-12 exhibited excellent CO yields.
On the other hand, the catalysts of Comparative Examples 1 and 2 were capable of producing CO even under low-temperature conditions of a reaction temperature of 250°C, but compared with the catalysts of Examples 1-12, the production of CO Poor speed and yield.

Claims (11)

A reverse water gas shift reaction catalyst used for producing carbon monoxide from carbon dioxide and hydrogen, wherein the reverse water gas shift reaction catalyst comprises a metal oxide support and a composite oxidation supported on the metal oxide support. and a metal catalyst,
The composite oxide includes, as a first metal oxide, an oxide of at least one metal element selected from the group consisting of Group 4 elements, Group 5 elements, and Group 6 elements;
an oxide of at least one metal element selected from the group consisting of Group 1 elements and Group 2 elements as the second metal oxide;
A catalyst for the reverse water gas shift reaction, comprising: The reverse water gas shift reaction catalyst according to claim 1, wherein said metal oxide support is _TiO2 . The reverse water gas shift reaction catalyst according to claim 1 or 2, wherein the metal catalyst is Pt. The reverse water according to any one of claims 1 to 3, wherein the first metal oxide is an oxide of at least one metal element selected from the group consisting of Mo, V, Nb, and W. Catalyst for gas shift reaction. The second metal oxide according to any one of claims 1 to 4, wherein the second metal oxide is an oxide of at least one metal element selected from the group consisting of Rb, Cs, Ca, Sr, and Ba. catalyst for the reverse water gas shift reaction of The reverse water gas shift reaction catalyst according to any one of claims 1 to 5, wherein the first metal oxide is a Mo oxide. 7. The reverse water gas shift reaction catalyst according to claim 6, wherein the content of said Mo oxide is 0.2 to 3.0% by mass as Mo metal element based on the total amount of said reverse water gas shift reaction catalyst. The reverse water gas shift reaction catalyst according to any one of claims 1 to 7, wherein the composite oxide further contains a lanthanide oxide as a third metal oxide. 9. The method according to claim 8, wherein the third metal oxide is an oxide of at least one metal element selected from the group consisting of La, Ce, Pr, Nd, Eu, Gd, Dy, Er, and Lu. A catalyst for the reverse water gas shift reaction as described. A reverse water gas shift reaction step of contacting a raw material gas containing carbon dioxide and hydrogen with the reverse water gas shift reaction catalyst according to any one of claims 1 to 9 to obtain a product gas containing carbon monoxide. ,
A method for producing carbon monoxide. The method for producing carbon monoxide according to claim 10, wherein the reaction temperature of the reverse water gas shift reaction step is 100 to 400°C.