JP2009120916A - Platinum-ruthenium-containing mixed particulate thin film, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a platinum-ruthenium-containing mixed particulate thin film utilizable for a fuel cell, and to provide a method for producing the same. <P>SOLUTION: Disclosed is a platinum-ruthenium-containing mixed particulate thin film obtained by substantially simultaneously feeding an organic platinum complex and an organic ruthenium complex, so as to form a platinum-ruthenium-containing thin film by a chemical vapor deposition process. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a platinum and ruthenium-containing mixed fine particle thin film produced by a chemical vapor deposition method (hereinafter referred to as a CVD method) using an organic platinum complex and an organic ruthenium complex, and a method for producing the same. About.

In recent years, for example, secondary batteries, solar cells, fuel cells and the like have been developed as batteries. Among these, the fuel cell is attracting attention as a clean energy source because electricity is obtained from the reaction between a hydrogen source and oxygen, and the substance by-produced at that time is water. In the development of this fuel cell, the development of a catalyst for a fuel cell is one of the important projects, and research to increase the catalyst efficiency is being conducted. As such a catalyst, a platinum catalyst has been mainly studied, and studies on fine particles and high dispersion have been actively conducted. In addition, platinum and ruthenium catalysts in which ruthenium is mixed with platinum have been studied as measures for preventing the deactivation of the platinum catalyst, and further studies are being made on making the mixed catalyst fine particles (for example, Patent Document 1 and non-patent documents). Reference 1).
As a method for producing a platinum and ruthenium mixed metal catalyst, for example, a platinum salt or ruthenium salt raw material is dissolved in water, and then these metals are supported on a support such as activated carbon by a reduction reaction (solution precipitation method). ) (See, for example, Patent Document 1). However, in this method, it is difficult to make the metal highly dispersed and fine particles, which may cause a problem in the catalyst performance. Furthermore, using an acetylacetonatoplatinum complex and an acetylacetonatoruthenium complex as metal raw materials, dissolving these metal complexes in an organic solvent and reacting them, the platinum and ruthenium mixed fine particles were precipitated from the reaction system, A method of taking out fine particles of platinum and ruthenium through a separation operation is disclosed (for example, see Non-Patent Document 1). However, in this method, the operation of separating the platinum and ruthenium fine particles from the solvent used is complicated, which is a problem as an industrial production method.
JP 2006-277992 A Chem. Mater., 18, 4946 (2006)

  An object of the present invention is to solve the above problems and to provide a mixed fine particle thin film containing platinum and ruthenium and a method for producing the same.

  An object of the present invention is to provide a platinum and ruthenium-containing mixed fine particle thin film obtained by supplying an organic platinum complex and an organic ruthenium complex substantially simultaneously and forming a thin film containing platinum and ruthenium by chemical vapor deposition. Solved by.

  According to the present invention, a platinum and ruthenium-containing mixed fine particle thin film that can be used for a fuel cell by a chemical vapor deposition method (hereinafter referred to as a CVD method) using an organic platinum complex and an organic ruthenium complex, and The manufacturing method can be provided.

  In the present invention, for example, an organic platinum complex and an organic ruthenium complex are used, and these complexes are supplied at substantially the same time, and a mixed fine particle thin film containing platinum and ruthenium is formed on a carrier (for example, on a silicon substrate, activated carbon) by a CVD method. Sheet). The particle diameter of each of the platinum fine particles and ruthenium fine particles at that time is preferably 1 to 10 nm, and more preferably 2 to 8 nm. In addition, supplying substantially simultaneously indicates supplying the vaporized complex so as to form a mixed state inside the vaporizer. The term “mixing” refers to a state where the particles are physically dispersed, and further, a state where the platinum fine particles and the ruthenium fine particles are physically dispersed randomly. However, there may be cases where they are gathered by some electrical interaction.

  In the present invention, a platinum and ruthenium-containing mixed fine particle thin film is produced by an CVD method using an organic platinum complex and an organic ruthenium complex, and is preferably performed in the presence of a hydrogen source, an oxygen source or an inert gas. Hydrogen gas is preferably used as the hydrogen source, and oxygen gas is preferably used as the oxygen source. Moreover, as an inert gas, nitrogen, helium, argon etc. are used suitably, for example.

  The organic platinum complex used in the present invention has the general formula (1)

(In the formula, X ¹ and Y ¹ are a linear or branched alkyl group having 2 to 10 carbon atoms in total which may be substituted with an alkoxy group, and Z ¹ is a hydrogen atom or 1 carbon atom. -4 represents a linear or branched alkyl group, and L ¹ represents an alkoxyalkenyl group (an alkenyl group substituted with an alkoxy group).
Is preferably used.

In the general formula (1), X ¹ and Y ¹ represent a total of 2 to 10 straight or branched alkyl groups that may be substituted with an alkyl group. For example, methyl Group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, 1-methoxyethyl group, 1-ethoxyethyl group, etc. And preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or a 1-methoxyethyl group. Z ¹ represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group , T-butyl group and the like.

L ¹ represents an alkoxyalkenyl group (an alkenyl group substituted with an alkoxy group). For example, 2-methoxy-5-hexenyl group, 2-methoxy-4-pentenyl group, 2-methoxy-3-butenyl Group, 2-ethoxy-5-hexenyl group, 2-ethoxy-4-pentenyl group, 2-ethoxy-3-butenyl group, 2-butoxy-5-hexenyl group, 2-butoxy-4-pentenyl group, 2-butoxy -3-butenyl group, 1-methyl-2-methoxy-3-pentenyl group, 1-methyl-2-ethoxy-3-pentenyl group and the like are preferable, but 2-methoxy-5-hexenyl group, 2- A methoxy-4-pentenyl group, a 2-ethoxy-5-hexenyl group, and a 2-ethoxy-4-pentenyl group;

  Specifically, the platinum complex is, for example, (acetylacetonato) (2-methoxy-5-hexenyl) platinum (II), (acetylacetonato) (2-ethoxy-5-hexenyl) platinum (II), (2-methoxy-6-methyl-3,5-heptanedionato) (2-methoxy-5-hexenyl) platinum (II), (2-methoxy-6-methyl-3,5-heptaneedionato) (2-ethoxy-5 -Hexenyl) platinum (II) and the like.

  On the other hand, the organoruthenium complex used in the present invention has the general formula (2)

(In the formula, X ² and Y ² are a linear or branched alkyl group having 2 to 10 carbon atoms in total which may be substituted with an alkoxy group, Z ² is a hydrogen atom or 1 carbon atom) Represents a hydrocarbon group of ˜4, and L ² represents an unsaturated hydrocarbon compound having at least two double bonds.
A ruthenium complex represented by is preferably used.

In the general formula (2), X ² and Y ² are linear or branched alkyl groups having 2 to 10 carbon atoms in total which may be substituted with alkoxy groups. Group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, 1-methoxyethyl group, 1-ethoxyethyl group, etc. And preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or a 1-methoxyethyl group. Z ² represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, etc. It is.

L ² represents an unsaturated hydrocarbon compound having at least two double bonds, such as 1,5-hexadiene, 1,5-cyclooctadiene, norbornadiene, 1,4-cyclohexadiene, 2, 5-dimethyl-2,4-hexadiene, 4-vinyl-1-cyclohexene, 1,3-pentadiene, 1,4-hexadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-pentadiene, 3- Examples include methyl-1,3-pentadiene, 2-methyl-1,4-pentadiene, 4-vinyl-1-cyclohexene or 1.3-pentadiene, preferably 1,5-hexadiene, 2,5-dimethyl-2, 4-hexadiene, 1,3-pentadiene, 1,4-hexadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, or 2-methyl-1 1,4-pentadiene is preferably used.

  Specific examples of the organic ruthenium complex include bis (acetylacetonato) (1,5-hexadiene) ruthenium, bis (acetylacetonato) (1,3-pentadiene) ruthenium, and bis (acetylacetonato). (2,4-hexadiene) ruthenium, bis (2-methoxy-6-methyl-3,5-heptanedionato) (1,5-hexadiene) ruthenium.

  The β-diketone which is the base of β-diketonato which is a ligand of the organoruthenium complex of the present invention is a compound that can be easily synthesized by a known method.

  In the present invention, in order to form a ruthenium thin film by the CVD method, it is necessary to vaporize the organic platinum complex and the organic ruthenium complex. As a method for vaporizing the organic platinum complex and the organic ruthenium complex of the present invention, for example, In addition, the organic platinum complex and the organic ruthenium complex itself may be vaporized by filling or transporting them to the same or different vaporization chambers. Aliphatic hydrocarbons such as octane; aromatic hydrocarbons such as toluene; ethers such as tetrahydrofuran and dibutyl ether, etc. (They may be the same or different.) The method of vaporizing by introducing into the vaporizing chamber with a pump (solution method) can also be used. .

  As a method for depositing each metal on a film formation target (for example, a substrate, activated carbon sheet, activated carbon powder, etc.), it can be performed by a known CVD method, for example, under normal pressure or reduced pressure, preferably hydrogen. A method in which the organic platinum complex and the organic ruthenium complex are sent onto a heated substrate substantially simultaneously with the source, the oxygen source, or the inert gas to deposit platinum and ruthenium fine particle thin films can be used. Moreover, the method of vapor-depositing a platinum and ruthenium containing mixed fine particle thin film by plasma CVD method can also be used.

  When depositing the platinum and ruthenium-containing mixed fine particle thin film, the pressure in the reaction system is preferably 1 Pa to 200 kPa, more preferably 10 Pa to 110 kPa, and the temperature of the film formation target is preferably 30 to 500 ° C., More preferably, it is 70-450 degreeC. Further, the content ratio of the metal thin film by the hydrogen source or oxygen source to the total gas amount is preferably 0.05 to 95% by volume, more preferably 0.1 to 90% by volume (the rest is an inert gas). is there).

  As the carrier for supporting the platinum and ruthenium-containing mixed fine particle thin film, for example, a carbon material that is a conductive substance such as a carbon sheet or carbon powder; a metal oxide carrier such as alumina, silica, or magnesia is used. As the substrate, for example, a silicon substrate, a silicon substrate on which a titanium nitride film is formed, or the like is used.

  Next, the present invention will be specifically described with reference to examples, but the scope of the present invention is not limited thereto.

Reference Example 1 (Synthesis of (acetylacetonato) (2-ethoxy-5-hexenyl) platinum (II) (hereinafter referred to as [Pt (acac) (eoh)])
To a 100 ml flask equipped with a stirrer, thermometer and dropping funnel, sodium ethoxide 3.53 g (18.3 mmol) and ethanol 8 ml were added, and dichloro (1,5-hexadiene) platinum (II) 1.62 g under water cooling. A solution in which (4.66 mmol) was dissolved in 12 ml of methylene chloride was added dropwise. Next, 3.00 g (30.0 mmol) of acetylacetone was added, and the mixture was reacted at the same temperature for 1 hour with stirring. After completion of the reaction, the organic layer was separated from the reaction solution, washed with water, and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (140 ° C., 33 Pa) to give (acetylacetonato) (2-ethoxy-5-hexenyl) platinum (II) as a pale yellow viscous liquid viscous liquid 1.71 g was obtained (isolation yield; 87%).
Note that (acetylacetonato) (2-ethoxy-5-hexenyl) platinum (II) is a novel compound represented by the following physical property values.

IR (neat (cm ^-1 )); 2971, 2926, 1583, 1516, 1389, 1265, 1083, 780, 614, 447
(The peak peculiar to β-diketone (1622 cm ^-1 ) disappeared and the peak peculiar to β-diketonato (1583 cm ^-1 ) was observed.)
Elemental analysis (C ₁₃ H ₂₂ O ₃ Pt); carbon: 37.1%, hydrogen: 5.30%, platinum: 46.3%
(Theoretical value: Carbon: 37.05%, Hydrogen: 5.26%, Platinum: 46.29%)
MS (m / e); 421, 376, 321, 276, 235, 43

Reference Example 2 (Synthesis of bis (acetylacetonato) (1,5-hexadiene) ruthenium (II) (hereinafter referred to as [Ru (acac) ₂ (hd)])
To a 100-ml flask equipped with a stirrer, thermometer and dropping funnel, add 8.87 g (33.9 mmol) of ruthenium trichloride trihydrate, 6.12 g (74.5 mmol) of 1,5-hexadiene and 60 ml of isopropyl alcohol. Then, the mixture was reacted at 70 ° C. for 4 hours with stirring, and then an aqueous solution in which 10.6 g (106 mmol) of acetylacetone and 4.22 g (106 mmol) of sodium hydroxide were mixed was added dropwise and reacted for 0.5 hour with stirring. After completion of the reaction, 60 ml of methylcyclohexane and 30 ml of water were added, and the organic layer was separated and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (140 ° C., 39 Pa) to obtain 10.3 g of bis (acetylacetonato) (1,5-hexadiene) ruthenium (II) as a tan viscous liquid. (Isolation yield: 80%).
Note that bis (acetylacetonato) (1,5-hexadiene) ruthenium (II) is a novel compound represented by the following physical property values.

IR (neat (cm ^-1 )); 3076, 2923, 1576, 1517, 1400, 1268, 1201, 1022, 933, 767, 620, 432
(The peak specific to β-diketone (1622 cm ^-1 ) disappeared, and the peak specific to β-diketonato (1576 cm ^-1 ) was observed.)
Elemental analysis (C ₁₆ H ₂₄ O ₄ Ru); carbon: 50.2%, hydrogen: 6.45%, ruthenium: 26.3%
(Theoretical value: Carbon: 50.4%, Hydrogen: 6.34%, Ruthenium: 26.5%)
MS (m / e); 382, 300, 43

Examples 1 and 2 (deposition experiment; production of a novel metal-containing thin film)
Organoplatinum complexes ((acetylacetonato) (2-ethoxy-5-hexenyl) platinum (II); [Pt (acac) (eoh)]) and organoruthenium complexes (bis (acetyl)) obtained in Reference Examples 1 and 2 Using acetonato) (1,5-hexadiene) ruthenium (II); [Ru (acac) ₂ (hd)]), platinum and ruthenium-containing mixed fine particle thin films were produced, and the film characteristics were evaluated. As the carrier, a carbon sheet and a silicon substrate with a silicon oxide film were used.

  The apparatus shown in FIG. 1 was used for the evaluation test. The organic platinum complex 20 in the vaporizer 5 (glass ampule) and the organic ruthenium complex 21 in the vaporizer 6 (glass ampule) are heated and vaporized by the heaters 12A and 12B, and preheated via the mass flow controllers 1A and 1B. The vaporizers 5 and 6 exit from the helium gas introduced after preheating in the vaporizers 11A and 11B, respectively. The gas exiting the vaporizer 5 or 6 is introduced into the reactor 7 substantially simultaneously with the hydrogen gas or oxygen gas introduced through the mass flow controller 1C and the stop valve 4 as necessary. The pressure in the reaction system is controlled to a predetermined pressure by opening and closing the valve 9 in front of the vacuum pump, and is monitored by the pressure gauge 8. The central part of the glass reactor has a structure that can be heated by the heater 12C. The platinum complex introduced into the reactor is set at the center of the reactor, reacts on the surface of the deposition substrate 21 heated to a predetermined temperature by the heater 12C, and platinum and ruthenium-containing mixed fine particles are formed on the substrate 21. A thin film is deposited. The gas exiting the reactor 7 is exhausted to the atmosphere via a trap 10 and a vacuum pump.

  The deposition conditions and deposition results (film characteristics) are shown in Table 1. Note that a 6 mm × 20 mm rectangular substrate was used as the deposition base.

  The SEM photograph and TEM photograph of the film | membrane obtained by each Example were shown in FIG.2 and FIG.3. According to this, it can be seen that a platinum and ruthenium-containing mixed fine particle thin film having a particle diameter of 3 nm or less is formed.

From the results, platinum and ruthenium-containing mixtures were formed by CVD using an organic platinum complex (eg, [Pt (acac) (eoh)]) and an organic ruthenium complex (eg, [Ru (acac) ₂ (hd)]). It turns out that a fine particle thin film is obtained.

  The present invention relates to a platinum and ruthenium-containing mixed fine particle thin film that can be used as a fuel cell by an organic platinum complex and an organic ruthenium complex by a chemical vapor deposition method (hereinafter referred to as a CVD method). It relates to the manufacturing method.

It is a figure which shows the structure of a vapor deposition apparatus. 2 is an SEM photograph of platinum and ruthenium-containing mixed fine particle thin film synthesized by the method of Example 1. 3 is a TEM photograph of a platinum and ruthenium-containing mixed fine particle thin film synthesized by the method of Example 2. FIG.

Claims (11)

  A platinum and ruthenium-containing mixed fine particle thin film obtained by supplying an organic platinum complex and an organic ruthenium complex substantially simultaneously and forming a thin film containing platinum and ruthenium by chemical vapor deposition.   The platinum and ruthenium-containing mixture according to claim 1, wherein the organic platinum complex and the organic ruthenium complex are supplied substantially simultaneously to form a mixed fine particle thin film containing platinum and ruthenium by chemical vapor deposition. Manufacturing method of fine particle thin film.   The method for producing a platinum and ruthenium-containing mixed fine particle thin film according to claim 1, wherein each of the platinum fine particles and the ruthenium fine particles has a particle diameter of 2 to 8 nm. The organic platinum complex has the general formula (1)

(In the formula, X ¹ and Y ¹ are a linear or branched alkyl group having 2 to 10 carbon atoms in total which may be substituted with an alkoxy group, and Z ¹ is a hydrogen atom or 1 carbon atom. -4 represents a linear or branched alkyl group, and L ¹ represents an alkoxyalkenyl group (an alkenyl group substituted with an alkoxy group).
The production method according to claim 1, wherein the compound is represented by the formula: The organic ruthenium complex has the general formula (2)

(In the formula, X ² and Y ² are a linear or branched alkyl group having 2 to 10 carbon atoms in total which may be substituted with an alkoxy group, Z ² is a hydrogen atom or 1 carbon atom) Represents a hydrocarbon group of ˜4, and L ² represents an unsaturated hydrocarbon compound having at least two double bonds.
The production method according to claim 2, which is a compound represented by the formula:   Unsaturated hydrocarbon compounds having at least two double bonds are 1,5-hexadiene, 1,5-cyclooctadiene, norbornadiene, 1,4-cyclohexadiene, 2,5-dimethyl-2,4-hexadiene, 4-vinyl-1-cyclohexene, 1,3-pentadiene, 1,4-hexadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 2- The process according to claim 5, which is methyl-1,4-pentadiene, 4-vinyl-1-cyclohexene or 1.3-pentadiene.   An organic platinum complex and an organic ruthenium complex are supplied substantially simultaneously in the presence of a hydrogen source, an oxygen source or an inert gas, and a mixed fine particle film containing platinum and ruthenium is formed by chemical vapor deposition. 2. The production method according to 2.   The production method according to claim 7, wherein the hydrogen source is hydrogen gas.   The production method according to claim 7, wherein the oxygen source is oxygen gas.   The manufacturing method of Claim 2 or 7 which uses the solution which melt | dissolved the organic platinum complex and the organic ruthenium complex in the organic solvent as a platinum and ruthenium supply source.   The production method according to claim 10, wherein the solvent used is at least one solvent selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons and ethers.

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