JPWO2018159644A1 - PdRu solid solution nanoparticles, method for producing the same and catalyst, method for controlling crystal structure of PtRu solid solution nanoparticles, and AuRu solid solution nanoparticles and method for producing the same - Google Patents

PdRu solid solution nanoparticles, method for producing the same and catalyst, method for controlling crystal structure of PtRu solid solution nanoparticles, and AuRu solid solution nanoparticles and method for producing the same Download PDF

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JPWO2018159644A1
JPWO2018159644A1 JP2019503039A JP2019503039A JPWO2018159644A1 JP WO2018159644 A1 JPWO2018159644 A1 JP WO2018159644A1 JP 2019503039 A JP2019503039 A JP 2019503039A JP 2019503039 A JP2019503039 A JP 2019503039A JP WO2018159644 A1 JPWO2018159644 A1 JP WO2018159644A1
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北川 宏
宏 北川
康平 草田
康平 草田
冬霜 ▲呉▼
冬霜 ▲呉▼
権 張
権 張
徹也 池渕
徹也 池渕
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    • B01J23/40Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
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    • B01J37/00Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
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    • B22F9/24Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
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    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C5/02Alloys based on gold
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
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    • C22C5/04Alloys based on a platinum group metal
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells

Abstract

本発明は、次の三つを提供する。第一に、式PdxRu1−x(0.1≦x≦0.8)で表される、PdとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)であるPdRu固溶体ナノ粒子を提供する。第二に、PtRu固溶体において、還元剤の加熱温度を制御することにより、PtRu固溶体の結晶構造を制御する方法を提供する。第三に、式AuzRu1−z(0.05≦z≦0.4)で表される、AuとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)又は面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子を提供する。The present invention provides the following three. First, PdRu represented by the formula PdxRu1-x (0.1 ≦ x ≦ 0.8), in which Pd and Ru form a solid solution at the atomic level and have a main structure of a hexagonal close-packed structure (hcp) Provide solid solution nanoparticles. Second, the present invention provides a method for controlling the crystal structure of the PtRu solid solution by controlling the heating temperature of the reducing agent in the PtRu solid solution. Third, Au and Ru represented by the formula AuzRu1-z (0.05 ≦ z ≦ 0.4) are dissolved at the atomic level, and the main structure is a hexagonal close-packed structure (hcp) or face center. AuRu solid solution nanoparticles having a cubic lattice structure (fcc) are provided.

Description

本発明は、PdRu固溶体ナノ粒子、その製造方法及び触媒、PtRu固溶体ナノ粒子の結晶構造を制御する方法、並びにAuRu固溶体ナノ粒子及びその製造方法に関する。  The present invention relates to PdRu solid solution nanoparticles, a method for producing the same and a catalyst, a method for controlling the crystal structure of PtRu solid solution nanoparticles, and an AuRu solid solution nanoparticle and a method for producing the same.

パラジウム(Pd)はレアメタルの一つであり、その微粒子は工業的には自動車の排気ガス浄化用の触媒(三元触媒)や家庭用燃料電池エネファームなどにおける電極触媒など、様々な反応の触媒として使われている。しかし、これらの触媒として用いられるパラジウム微粒子は、様々な化学反応の過程で生成されるCO(一酸化炭素)などによって被毒され、高出力で長時間使用する事が困難となっている。そのため、このような被毒による劣化を抑制する技術は盛んに研究されている。一方、白金族の一つであるルテニウム(Ru)はCOを酸化しCO2(二酸化炭素)とする触媒活性を有するために、CO被毒に耐久性を持つ。そのため、ルテニウムは実際に燃料電池の電極にCO被毒を抑制するために白金などと合金化され利用されている。しかし、パラジウムとルテニウムは平衡状態において原子レベルで混ざる(固溶する)ことが出来ない組み合わせであり分離してしまう。Palladium (Pd) is one of the rare metals, and its fine particles are industrially used as catalysts for various reactions, such as catalysts for purifying exhaust gas from automobiles (three-way catalysts) and electrode catalysts in household fuel cell ene farms. It is used as However, the fine palladium particles used as these catalysts are poisoned by CO (carbon monoxide) or the like generated in the course of various chemical reactions, making it difficult to use them for a long time at a high output. Therefore, techniques for suppressing such deterioration due to poisoning are being actively studied. On the other hand, ruthenium (Ru), which is a member of the platinum group, has catalytic activity to oxidize CO and convert it to CO 2 (carbon dioxide), and therefore has durability against CO poisoning. Therefore, ruthenium is actually alloyed and used with platinum or the like to suppress CO poisoning of fuel cell electrodes. However, palladium and ruthenium are combinations that cannot be mixed (dissolved) at the atomic level in an equilibrium state and are separated.

特許文献1は、PdとRuの2元合金を開示しているが、金を含む固溶体合金の開示はない。  Patent Document 1 discloses a binary alloy of Pd and Ru, but does not disclose a solid solution alloy containing gold.

特許文献2は、Pt,Ir,Pd,Rh,Ru,Au,Agのうちの少なくとも二種以上の固溶体を記載しているが、実施例ではIrとPtの固溶体が記載されるのみであり、他の固溶体については製造されていない。  Patent Document 2 describes at least two or more solid solutions of Pt, Ir, Pd, Rh, Ru, Au, and Ag. However, in Examples, only a solid solution of Ir and Pt is described. No other solid solutions have been produced.

特許文献3は実質的に面心立方構造を有するルテニウム微粒子群を開示しているが、合金に関する情報は開示されていない。  Patent Document 3 discloses a ruthenium fine particle group having a substantially face-centered cubic structure, but does not disclose information on alloys.

特許文献4はカーボン粉末に担持された白金とルテニウムの合金の微粒子を開示しているが、本発明のように反応条件により結晶構造を制御することは記載がない。  Patent Document 4 discloses fine particles of an alloy of platinum and ruthenium supported on carbon powder, but does not describe controlling the crystal structure by reaction conditions as in the present invention.

特許文献5,6は実施例にはPtRu合金が開示されているが、Ruがコア、白金がシェルの構造であり、固溶体合金ではない。  Patent Documents 5 and 6 disclose PtRu alloys in Examples, but have a structure in which Ru is a core and platinum is a shell, and are not solid solution alloys.

特許第5737699号Patent No. 5737699 特開2006-198490号公報JP 2006-198490 A 特許第5657805号Patent No. 5567805 特開2002-222655号公報JP 2002-222655 A 特開2012-41581号公報JP 2012-41581 A 特開2016-43314号公報JP 2016-43314 A

本発明は、PdとRuの固溶体において、触媒活性及び耐久性をさらに向上させることを目的とする。  An object of the present invention is to further improve catalytic activity and durability in a solid solution of Pd and Ru.

また、本発明は、PtRu固溶体において、結晶構造を制御することを目的とする。  Another object of the present invention is to control the crystal structure of a PtRu solid solution.

さらに、本発明は、所望の結晶構造を持つAuRu固溶体及びその製造方法を提供することを目的とする。  Still another object of the present invention is to provide an AuRu solid solution having a desired crystal structure and a method for producing the same.

本発明は、以下のPdRu固溶体ナノ粒子、その製造方法及び触媒、PtRu固溶体ナノ粒子の結晶構造を制御する方法、並びにAuRu固溶体ナノ粒子及びその製造方法を提供するものである。
項1. 式PdxRu1-x(0.1≦x≦0.8)で表わされる、 PdとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)であるPdRu固溶体ナノ粒子。
項2. 0.4≦x≦0.6である、項1に記載のナノ粒子。
項3. hcpの割合が80%以上である、項1又は2に記載のナノ粒子。
項4. hcpの割合が90%以上である、項3に記載のナノ粒子。
項5. 項1〜4のいずれか1項に記載のナノ粒子を担体に担持してなる触媒。
項6. 水添反応用触媒、水素酸化反応用触媒、酸素還元反応用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒又は水素燃料電池用触媒である、項5に記載の触媒。
項7. 水電解反応用触媒である、項6に記載の触媒。
項8. 面心立方格子構造(fcc)が主構造である式PdRu固溶体ナノ粒子を水素雰囲気で加熱してfcc結晶構造の一部または全部をhcp結晶構造に変換することを特徴とする、式Pd xRu1-x(0.1≦x≦0.8)で表わされる、Pd とRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)である固溶体ナノ粒子の製造方法。
項9. 液体還元剤を含む加熱溶液にPt化合物とRu化合物を含む溶液を添加する工程を含み、前記液体還元剤の加熱温度がPt化合物の還元温度〜前記還元温度+15℃であればhcpが主構造になり、前記液体還元剤の加熱温度がPt化合物の還元温度+15℃超であればfccが主構造になることを特徴とする、式PtyRu1-y(0.05≦y≦0.3)で表わされるPtRu固溶体ナノ粒子の結晶構造における六方最密構造(hcp)と面心立方格子(fcc)の割合を制御する方法。
項10. 式AuzRu1-z(0.05≦z≦0.4)で表わされる、 AuとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)又は面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子。
項11. 主構造が六方最密構造(hcp)である、項10に記載のAuRu固溶体ナノ粒子。
項12. 主構造が面心立方格子構造(fcc)である、項10に記載のAuRu固溶体ナノ粒子。
項13. 液体還元剤を含む加熱溶液にAu化合物とRu化合物を含む溶液を添加する工程を含む、主構造が面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子の製造方法。
項14. CTAB(Cetyl trimethyl ammonium bromide)と液体還元剤を含む加熱溶液にAu化合物とRu化合物を含む溶液を添加する工程を含む、主構造が六方最密構造(hcp)であるAuRu固溶体ナノ粒子の製造方法。
項15. 項11又は12に記載のナノ粒子を担体に担持してなり、水添反応用触媒、水素酸化反応用触媒、酸素還元反応用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒又は水素燃料電池用触媒である、触媒。
The present invention provides the following PdRu solid solution nanoparticles, a method for producing the same and a catalyst, a method for controlling the crystal structure of PtRu solid solution nanoparticles, and a AuRu solid solution nanoparticle and a method for producing the same.
Item 1. PdRu solid solution nanoparticles represented by the formula Pd x Ru 1-x (0.1 ≦ x ≦ 0.8), in which Pd and Ru form a solid solution at the atomic level and have a main structure of a hexagonal close-packed structure (hcp).
Item 2. Item 2. The nanoparticles according to Item 1, wherein 0.4 ≦ x ≦ 0.6.
Item 3. Item 3. The nanoparticles according to Item 1 or 2, wherein the proportion of hcp is 80% or more.
Item 4. Item 4. The nanoparticles according to Item 3, wherein the proportion of hcp is 90% or more.
Item 5. Item 5. A catalyst comprising the nanoparticle according to any one of Items 1 to 4 supported on a carrier.
Item 6. Catalyst for hydrogenation reaction, catalyst for hydrogen oxidation reaction, catalyst for oxygen reduction reaction, catalyst for oxygen evolution reaction (OER), catalyst for hydrogen evolution reaction (HER), catalyst for nitrogen oxide (NOx) reduction reaction, carbon monoxide Item 6. The catalyst according to Item 5, which is a (CO) oxidation reaction catalyst, a dehydrogenation reaction catalyst, a VVOC or VOC oxidation reaction catalyst, an exhaust gas purification catalyst, a water electrolysis reaction catalyst, or a hydrogen fuel cell catalyst.
Item 7. Item 7. The catalyst according to Item 6, which is a catalyst for a water electrolysis reaction.
Item 8. The formula Pd x Ru, wherein the PdRu solid solution nanoparticles having a face-centered cubic lattice structure (fcc) as a main structure are heated in a hydrogen atmosphere to convert a part or all of the fcc crystal structure to an hcp crystal structure. A method for producing solid solution nanoparticles represented by 1-x (0.1 ≦ x ≦ 0.8) in which Pd and Ru form a solid solution at an atomic level and have a main structure of a hexagonal close-packed structure (hcp).
Item 9. The method includes a step of adding a solution containing a Pt compound and a Ru compound to a heating solution containing a liquid reducing agent, and if the heating temperature of the liquid reducing agent is from the reduction temperature of the Pt compound to the reduction temperature + 15 ° C, hcp is the main structure. If the heating temperature of the liquid reducing agent is higher than the reduction temperature of the Pt compound + 15 ° C., fcc has a main structure, and is represented by the formula Pt y Ru 1-y (0.05 ≦ y ≦ 0.3). A method of controlling the ratio of hexagonal close-packed structure (hcp) and face-centered cubic lattice (fcc) in the crystal structure of PtRu solid solution nanoparticles.
Item 10. Au and Ru represented by the formula Au z Ru 1-z (0.05 ≦ z ≦ 0.4), and Au and Ru form a solid solution at the atomic level, and the main structure is a hexagonal close-packed structure (hcp) or a face-centered cubic lattice structure (fcc) AuRu solid solution nanoparticles.
Item 11. Item 11. The AuRu solid solution nanoparticles according to Item 10, wherein the main structure is a hexagonal close-packed structure (hcp).
Item 12. Item 11. The AuRu solid solution nanoparticles according to Item 10, wherein the main structure is a face-centered cubic lattice structure (fcc).
Item 13. A method for producing AuRu solid solution nanoparticles whose main structure is a face-centered cubic lattice structure (fcc), comprising a step of adding a solution containing an Au compound and a Ru compound to a heating solution containing a liquid reducing agent.
Item 14. A method for producing AuRu solid solution nanoparticles whose main structure is a hexagonal close-packed structure (hcp), including a step of adding a solution containing an Au compound and a Ru compound to a heating solution containing CTAB (Cetyl trimethyl ammonium bromide) and a liquid reducing agent .
Item 15. Item wherein the nanoparticles according to claim 11 or 12 are carried on a carrier, a catalyst for hydrogenation reaction, a catalyst for hydrogen oxidation reaction, a catalyst for oxygen reduction reaction, a catalyst for oxygen evolution reaction (OER), a hydrogen evolution reaction (HER) Catalyst, nitrogen oxide (NOx) reduction reaction catalyst, carbon monoxide (CO) oxidation reaction catalyst, dehydrogenation reaction catalyst, VVOC or VOC oxidation reaction catalyst, exhaust gas purification catalyst, water electrolysis catalyst or A catalyst that is a catalyst for hydrogen fuel cells.

PdとRuを含む金属微粒子は様々な反応で用いられる有用な触媒であり、本発明によれば、これまでにない高い活性及び耐久性を有する触媒を開発することができる。  Metal fine particles containing Pd and Ru are useful catalysts used in various reactions, and according to the present invention, a catalyst having unprecedentedly high activity and durability can be developed.

PtとRuを含む触媒の結晶構造は、組成によりほぼ決まっていたが、本発明によれば、PtRu固溶体ナノ粒子の製造温度を制御することにより、結晶構造におけるhcpとfccの比率を自由に制御できるようになった。  Although the crystal structure of the catalyst containing Pt and Ru was almost determined by the composition, according to the present invention, the ratio of hcp to fcc in the crystal structure can be freely controlled by controlling the production temperature of PtRu solid solution nanoparticles. Now you can.

AuとRuは本来固溶しない合金系である。本発明によれば、従来存在しなかった、主構造がfcc又はhcpのAuRu固溶体を作製することで、新たな電子状態及び反応場として結晶表面を作ることが可能になり、このようなAuRu固溶体は、Au単体、Ru単体、非固溶体とは異なる触媒活性を有すると考えられる。  Au and Ru are alloys that do not form a solid solution. According to the present invention, it was possible to create a crystal surface as a new electronic state and a reaction field by preparing an AuRu solid solution having a main structure of fcc or hcp, which did not exist conventionally, and such an AuRu solid solution Is considered to have a different catalytic activity from Au alone, Ru alone, and non-solid solution.

実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子の粉末X線回折の結果Results of powder X-ray diffraction of Pd 0.4 Ru 0.6 solid solution nanoparticles obtained in Example 1 種々の反応時間での実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子の粉末X線回折の結果、およびその回折パターンのRietveld解析から得られたhcp構造の割合Results of powder X-ray diffraction of Pd 0.4 Ru 0.6 solid solution nanoparticles obtained in Example 1 at various reaction times, and the percentage of hcp structure obtained from Rietveld analysis of the diffraction pattern 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子のTEM像TEM image of Pd 0.4 Ru 0.6 solid solution nanoparticles obtained in Example 1 カーボンに担持されたPd0.4Ru0.6固溶体ナノ粒子の粉末X線回折の結果Results of powder X-ray diffraction of Pd 0.4 Ru 0.6 solid solution nanoparticles supported on carbon 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子のHAADF-STEM像およびSTEM-EDXマップHAADF-STEM image and STEM-EDX map of Pd 0.4 Ru 0.6 solid solution nanoparticles obtained in Example 1 実施例2で得られたPd0.5Ru0.5固溶体ナノ粒子の粉末X線回折の結果、およびその回折パターンのRietveld解析から得られたhcp構造の割合Results of powder X-ray diffraction of Pd 0.5 Ru 0.5 solid solution nanoparticles obtained in Example 2, and the ratio of hcp structure obtained from Rietveld analysis of the diffraction pattern 実施例2で得られたPd0.5Ru0.5固溶体ナノ粒子のTEM像TEM image of Pd 0.5 Ru 0.5 solid solution nanoparticles obtained in Example 2 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子触媒を用いた酸素発生反応(酸性水溶液)Oxygen generation reaction (acidic aqueous solution) using Pd 0.4 Ru 0.6 solid solution nanoparticle catalyst obtained in Example 1 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子触媒を用いた酸素発生反応(アルカリ性水溶液)Oxygen generation reaction using Pd 0.4 Ru 0.6 solid solution nanoparticle catalyst obtained in Example 1 (alkaline aqueous solution) 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子触媒を用いた酸素還元反応(アルカリ水溶液)Oxygen reduction reaction using Pd 0.4 Ru 0.6 solid solution nanoparticle catalyst obtained in Example 1 (aqueous alkaline solution) 実施例2で得られたPd0.5Ru0.5固溶体ナノ粒子触媒を用いた酸素発生反応(酸性水溶液)Oxygen generation reaction using Pd 0.5 Ru 0.5 solid solution nanoparticle catalyst obtained in Example 2 (acidic aqueous solution) 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子の耐久性試験(ADT test)後のTEM像TEM image of Pd 0.4 Ru 0.6 solid solution nanoparticles obtained in Example 1 after durability test (ADT test) 実施例1で得られたPd0.4Ru0.6固溶体ナノ粒子のX線光電子分光スペクトル(fcc&hcp)X-ray photoelectron spectroscopy (fcc & hcp) of Pd 0.4 Ru 0.6 solid solution nanoparticles obtained in Example 1 実施例3,4で得られたPtRu固溶体ナノ粒子のXRDパターンとTEM像XRD pattern and TEM image of PtRu solid solution nanoparticles obtained in Examples 3 and 4 実施例5,6で得られたPtRu固溶体ナノ粒子のXRDパターンとTEM像XRD pattern and TEM image of PtRu solid solution nanoparticles obtained in Examples 5 and 6 比較例1で得られたPtRu固溶体ナノ粒子のXRDパターンとTEM像XRD pattern and TEM image of PtRu solid solution nanoparticles obtained in Comparative Example 1 実施例7、8で得られたAuRu固溶体ナノ粒子およびAuナノ粒子、Ruナノ粒子の(a)XRDパターン、(b)拡大図、(c) fcc-AuRu3のXRDパターンのhcp成分とfcc成分を用いたRietveld解析のフィッティング結果。78.5%(fcc)と21.5%(hcp)であった。(d) hcp-AuRu3のXRDパターンのhcp成分を用いたRietveld解析のフィッティング結果。AuRu solid solution nanoparticles and Au nanoparticles obtained in Example 7, 8, (a) XRD pattern of Ru nanoparticles, (b) an enlarged view, (c) hcp component and fcc component XRD patterns of fcc-AuRu 3 Fitting result of Rietveld analysis using. 78.5% (fcc) and 21.5% (hcp). (d) fitting result of Rietveld analysis using the hcp component XRD patterns of hcp-AuRu 3. 実施例7、8で得られたAuRu固溶体ナノ粒子のTEM像TEM image of AuRu solid solution nanoparticles obtained in Examples 7 and 8 実施例7で得られたhcp構造のAuRu固溶体ナノ粒子のHAADF-STEM像およびSTEM-EDXマップを示す。9 shows a HAADF-STEM image and a STEM-EDX map of AuRu solid solution nanoparticles having the hcp structure obtained in Example 7. 実施例8で得られたfcc構造のAuRu固溶体ナノ粒子のHAADF-STEM像およびSTEM-EDXマップを示す。9 shows a HAADF-STEM image and a STEM-EDX map of AuRu solid solution nanoparticles having an fcc structure obtained in Example 8. 参考例1及び実施例1で得られたfcc構造又はhcp構造が主成分のPd0.4Ru0 .6固溶体ナノ粒子触媒を用いた水素発生反応(HER、0.1 M HClO4酸性水溶液)。fccPdRuはPdに比べ活性が低いのに対し、hcpPdRuはPdよりも高い活性を示すことがわかる。Hydrogen generation reaction where fcc structure or the hcp structure obtained in Reference Example 1 and Example 1 using Pd 0.4 Ru 0 .6 solid solution nanoparticles catalyst main component (HER, 0.1 M HClO 4 aqueous acid). It can be seen that fccPdRu has lower activity than Pd, whereas hcpPdRu shows higher activity than Pd. 実施例7,8で得られたfcc構造又はhcp構造のAu0.3Ru0.7固溶体ナノ粒子触媒を用いた酸素発生反応(OER、0.05 M H2SO4酸性水溶液)。(a)fcc-Au0.3Ru0.7/C触媒によるOERのLSV 分極曲線、(b) hcp-Au0.3Ru0.7/C触媒によるOERのLSV 分極曲線。Ruは約1.5V以降、触媒の溶出に伴う活性の低下が観測されるが、fcc合金の場合は1.6V以降に徐々に活性の低下が見られ、測定回数に伴い活性が低下。一方、hcp合金では活性の低下は観測されず、5000回の測定でも活性を維持する。結晶構造制御による触媒特性の向上が観測された。Oxygen generation reaction (OER, 0.05 MH 2 SO 4 acidic aqueous solution) using the Au 0.3 Ru 0.7 solid solution nanoparticle catalyst having the fcc structure or the hcp structure obtained in Examples 7 and 8. (a) LSV polarization curve of OER with fcc-Au 0.3 Ru 0.7 / C catalyst, (b) LSV polarization curve of OER with hcp-Au 0.3 Ru 0.7 / C catalyst. The activity of Ru is observed to decrease with the elution of the catalyst after about 1.5 V. However, in the case of the fcc alloy, the activity gradually decreases after 1.6 V, and the activity decreases with the number of measurements. On the other hand, no decrease in activity was observed in the hcp alloy, and the activity was maintained even after 5000 measurements. An improvement in catalytic properties by controlling the crystal structure was observed.

本発明は、主構造が六方最密構造(hcp)である、PdRu固溶体ナノ粒子及びその製造方法並びに触媒(第1発明)、PtRu固溶体ナノ粒子の結晶構造を制御する方法(第2発明)、及び、主構造が六方最密構造(hcp)又は面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子及びその製造方法並びに触媒(第3発明)に関する。  The present invention has a hexagonal close-packed structure (hcp) as a main structure, PdRu solid solution nanoparticles, a method for producing the same, and a catalyst (first invention), a method for controlling the crystal structure of PtRu solid solution nanoparticles (second invention), The present invention also relates to AuRu solid solution nanoparticles having a hexagonal close-packed structure (hcp) or a face-centered cubic lattice structure (fcc), a method for producing the same, and a catalyst (third invention).

本明細書において、固溶体ナノ粒子の「主構造」がhcp又はfccとは、hcpとfccの合計を100%とした場合にhcp又はfccの割合が50%又はそれより高く、好ましくは55%以上、60%以上、65%以上、70%以上、75%以上、80%以上、85%以上、90%以上、95%以上又は100%であることを意味する。  In the present specification, the “main structure” of the solid solution nanoparticles is hcp or fcc, and the ratio of hcp or fcc is 50% or higher, preferably 55% or more, when the sum of hcp and fcc is 100%. , 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 100%.

固溶体ナノ粒子におけるhcpとfccの割合は、固溶体ナノ粒子のXRDを測定し、そのXRDパターンをTopas(Bruker AXS社製)、PDXL(Rigaku社製)、RIETAN-FP、GSASなどのソフトウェアでfcc(空間群Fm-3m)とhcp(空間群P 63/mmc)の2成分を用いたRietveld解析を行うことで、hcpとfccの合計を100%とした場合の各結晶構造(hcp、fcc)の割合として決定できる。例えば、図17(a)にはRu NPs、hcp-AuR3、fcc-AuR3、Au NPsのXRDパターンが示され、図17(c)にはfcc-AuR3のXRDパターンについてのTopas(Bruker AXS社製)を用いたRietveld解析によりfcc(78.5%)とhcp(21.5%)であると算出され、fccが主構造であることが実証されている。図17(d)にはhcp-AuR3のXRDパターンについてのTopas(Bruker AXS社製)を用いたRietveld解析の結果が示されている。したがって、本発明のPdRu、PtRu又はAuRu固溶体ナノ粒子の主構造がhcpであるかfccであるかは、XRDパターンの解析により確認できる。The ratio of hcp and fcc in the solid solution nanoparticles can be determined by measuring the XRD of the solid solution nanoparticles and analyzing the XRD pattern using software such as Topas (Bruker AXS), PDXL (Rigaku), RIETAN-FP, GSAS, etc. By performing Rietveld analysis using two components of the space group Fm-3m) and hcp (space group P 63 / mmc), each crystal structure (hcp, fcc) when the sum of hcp and fcc is 100% It can be determined as a percentage. For example, FIG. 17A shows the XRD pattern of Ru NPs, hcp-AuR 3 , fcc-AuR 3 , and Au NPs, and FIG. 17C shows Topas (Bruker) for the fcc-AuR 3 XRD pattern. Rietveld analysis using AXS) calculated fcc (78.5%) and hcp (21.5%), demonstrating that fcc is the main structure. Result of Rietveld analysis using Topas (Bruker AXS, Inc.) for XRD patterns of hcp-Aur 3 is shown in FIG. 17 (d). Therefore, whether the main structure of the PdRu, PtRu or AuRu solid solution nanoparticles of the present invention is hcp or fcc can be confirmed by XRD pattern analysis.

(1)第1発明
Pdはfcc構造を有し、Ruはhcp構造を有する。PdとRuからなる固溶体の結晶構造はfccとhcpの混ざりになり、Pdの割合が多くなるほどfccの割合が増加し、Ruの割合が多くなるほどhcpの割合が増加する。本発明ではPdRu固溶体ナノ粒子を還元性の水素雰囲気において加熱するか、真空もしくは不活性ガス雰囲気で加熱するとhcpの割合が増加し、加熱を続けると結晶構造はほぼ100%の割合でhcpに変換され、hcpの割合が増大するにつれて触媒活性及び耐久性が改善されることを見出した。PdRu固溶体ナノ粒子の加熱は、好ましくは200〜600℃程度、より好ましくは300〜500℃程度の温度で行うことができる。反応時間は、5分〜12時間程度、好ましくは10分〜5時間程度、より好ましくは20分〜3時間程度である。反応温度が低いほど反応時間が長くなる傾向にある。hcpの結晶構造の割合を高くする反応の雰囲気は水素雰囲気が特に好ましい。水素雰囲気の水素濃度としては、容量で5〜100%程度が挙げられる。
(1) First invention
Pd has an fcc structure, and Ru has an hcp structure. The crystal structure of the solid solution composed of Pd and Ru is a mixture of fcc and hcp. The proportion of fcc increases as the proportion of Pd increases, and the proportion of hcp increases as the proportion of Ru increases. In the present invention, heating the PdRu solid solution nanoparticles in a reducing hydrogen atmosphere or heating in a vacuum or inert gas atmosphere increases the proportion of hcp, and continuing heating converts the crystal structure to hcp at a rate of almost 100%. As a result, it was found that the catalytic activity and durability improved as the proportion of hcp increased. The heating of the PdRu solid solution nanoparticles can be performed at a temperature of preferably about 200 to 600 ° C, more preferably about 300 to 500 ° C. The reaction time is about 5 minutes to 12 hours, preferably about 10 minutes to 5 hours, more preferably about 20 minutes to 3 hours. The lower the reaction temperature, the longer the reaction time tends to be. The atmosphere of the reaction for increasing the proportion of the hcp crystal structure is particularly preferably a hydrogen atmosphere. The hydrogen concentration in the hydrogen atmosphere includes about 5 to 100% by volume.

PdRu固溶体ナノ粒子は、式PdxRu1-x(0.1≦x≦0.8)で表わされる。xの好ましい範囲は、0.12≦x≦0.75、より好ましくは0.15≦x≦0.7、さらに好ましくは0.17≦x≦0.65、特に0.2≦x≦0.6である。PdRu solid solution nanoparticles are represented by the formula Pd x Ru 1-x (0.1 ≦ x ≦ 0.8). The preferred range of x is 0.12 ≦ x ≦ 0.75, more preferably 0.15 ≦ x ≦ 0.7, even more preferably 0.17 ≦ x ≦ 0.65, especially 0.2 ≦ x ≦ 0.6.

PdRu固溶体ナノ粒子におけるhcp結晶構造の比率は、30%以上、40%以上、50%以上、60%以上、70%以上、80%以上、90%以上、95%以上、又は100%である。hcpの比率が高いほど、触媒性能、耐久性が向上するために好ましい。  The proportion of the hcp crystal structure in the PdRu solid solution nanoparticles is 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 100%. A higher hcp ratio is preferred because catalyst performance and durability are improved.

本発明のPdRu固溶体ナノ粒子の平均粒径は、1〜20 nm程度、好ましくは1〜15 nm程度、より好ましくは1〜10 nm程度、さらに好ましくは1〜6 nm程度である。平均粒径が小さいと触媒性能が高くなるために好ましい。固溶体ナノ粒子の平均粒径は、TEMなどの顕微鏡写真により確認することができる。固溶体ナノ粒子の形状は特に限定されず、球状、楕円体状、ロッド状、柱状、リン片状など任意の形状であってよい。  The average particle size of the PdRu solid solution nanoparticles of the present invention is about 1 to 20 nm, preferably about 1 to 15 nm, more preferably about 1 to 10 nm, and still more preferably about 1 to 6 nm. It is preferable that the average particle size is small because the catalyst performance becomes high. The average particle size of the solid solution nanoparticles can be confirmed by a micrograph such as a TEM. The shape of the solid solution nanoparticles is not particularly limited, and may be any shape such as a sphere, an ellipsoid, a rod, a column, and a scale.

本発明のPdRu固溶体ナノ粒子は、担体に担持されていてもよい。担体は特に制限はないが、具体的には酸化物類、窒化物類、炭化物類、単体炭素、単体金属などが担体として挙げられ、中でも酸化物類、単体炭素が好ましく、酸化物類が特に好ましい担体である。酸化物類としては、シリカ、アルミナ、セリア、チタニア、ジルコニア、ニオビアなどの酸化物や、シリカ−アルミナ、チタニア−ジルコニア、セリア−ジルコニア、チタン酸ストロンチウムなどの複合酸化物などが挙げられる。単体炭素としては、活性炭、カーボンブラック、グラファイト、カーボンナノチューブ、活性炭素繊維などが挙げられる。窒化物類としては、窒化ホウ素、窒化ケイ素、窒化ガリウム、窒化インジウム、窒化アルミニウム、窒化ジルコニウム、窒化バナジウム、窒化タングステン、窒化モリブデン、窒化チタン、窒化ニオブが挙げられる。炭化物類としては、炭化ケイ素、炭化ガリウム、炭化インジウム、炭化アルミニウム、炭化ジルコニウム、炭化バナジウム、炭化タングステン、炭化モリブデン、炭化チタン、炭化ニオブ、炭化ホウ素が挙げられる。単体金属としては、鉄、銅、アルミニウムなどの純金属及びステンレスなどの合金が挙げられる。  The PdRu solid solution nanoparticles of the present invention may be supported on a carrier. The carrier is not particularly limited, and specifically, oxides, nitrides, carbides, simple carbon, simple metal, and the like are mentioned as the carrier, among which oxides and simple carbon are preferable, and oxides are particularly preferable. Preferred carriers. Examples of the oxides include oxides such as silica, alumina, ceria, titania, zirconia, and niobium, and composite oxides such as silica-alumina, titania-zirconia, ceria-zirconia, and strontium titanate. Examples of the simple carbon include activated carbon, carbon black, graphite, carbon nanotube, and activated carbon fiber. Examples of the nitrides include boron nitride, silicon nitride, gallium nitride, indium nitride, aluminum nitride, zirconium nitride, vanadium nitride, tungsten nitride, molybdenum nitride, titanium nitride, and niobium nitride. Examples of the carbides include silicon carbide, gallium carbide, indium carbide, aluminum carbide, zirconium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, titanium carbide, niobium carbide, and boron carbide. Examples of the simple metal include pure metals such as iron, copper, and aluminum and alloys such as stainless steel.

本発明のPdRu固溶体ナノ粒子は、表面保護剤により被覆されていてもよい。表面保護剤としては、ポリビニルピロリドン(PVP)、ポリエチレングリコール(PEG)などのポリマー類、オレイルアミンなどのアミン類、オレイン酸などのカルボン酸類が挙げられる。  The PdRu solid solution nanoparticles of the present invention may be coated with a surface protective agent. Examples of the surface protective agent include polymers such as polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG), amines such as oleylamine, and carboxylic acids such as oleic acid.

本発明のPdRu固溶体ナノ粒子は、水添反応用触媒、水素酸化反応用触媒、酸素還元反応(ORR)用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒、水素燃料電池用触媒、炭化水素の酸化反応用触媒として優れており、水電解反応用触媒、三元触媒などの排ガス浄化触媒として好ましく使用される。三元触媒の場合、例えばNOxは窒素に還元され、COは二酸化炭素に酸化され、炭化水素(CH)は水と二酸化炭素に酸化される。  The PdRu solid solution nanoparticles of the present invention are a hydrogenation catalyst, a hydrogen oxidation reaction catalyst, an oxygen reduction reaction (ORR) catalyst, an oxygen evolution reaction (OER) catalyst, a hydrogen evolution reaction (HER) catalyst, and a nitrogen oxidation catalyst. (NOx) reduction catalyst, carbon monoxide (CO) oxidation reaction catalyst, dehydrogenation catalyst, VVOC or VOC oxidation reaction catalyst, exhaust gas purification catalyst, water electrolysis catalyst, hydrogen fuel cell catalyst It is excellent as a catalyst for hydrocarbon oxidation reaction, and is preferably used as a catalyst for exhaust gas purification such as a catalyst for water electrolysis reaction and a three-way catalyst. In the case of a three-way catalyst, for example, NOx is reduced to nitrogen, CO is oxidized to carbon dioxide, and hydrocarbons (CH) are oxidized to water and carbon dioxide.

本発明のhcp構造を富化させる前のPdRu固溶体ナノ粒子は公知であり、常法に従い製造できる。例えば、Pd化合物とRu化合物を含む混合水溶液と液体還元剤を準備し、液体還元剤にPd化合物とRu化合物を含む混合水溶液を加えて加熱下(例えば150〜250℃程度)に1分〜12時間程度撹拌下に反応し、その後に放冷し、遠心分離することにより、fcc構造を多く含むPdRu固溶体ナノ粒子を得ることができる。液体還元剤とPd化合物、Ru化合物の反応を担体の存在下に行うと、担体に担持されfcc構造を多く含むPdRu固溶体ナノ粒子が得られる。還元反応は加圧下に行ってもよい。  The PdRu solid solution nanoparticles before enrichment of the hcp structure of the present invention are known and can be produced according to a conventional method. For example, a mixed aqueous solution containing a Pd compound and a Ru compound and a liquid reducing agent are prepared, and a mixed aqueous solution containing a Pd compound and a Ru compound is added to the liquid reducing agent, and the mixture is heated for 1 minute to 12 minutes. By reacting with stirring for about an hour, and then allowed to cool and centrifuged, PdRu solid solution nanoparticles containing a large number of fcc structures can be obtained. When the reaction between the liquid reducing agent and the Pd compound or Ru compound is carried out in the presence of a carrier, PdRu solid solution nanoparticles supported on the carrier and containing a large number of fcc structures are obtained. The reduction reaction may be performed under pressure.

液体還元剤としては、メタノール、エタノール、イソプロパノールなどの低級アルコール、エチレングリコール、プロピレングリコールなどのアルキレングリコール類、ジエチレングリコール、ジプロピレングリコールなどのジアルキレングリコール類、トリエチレングリコール、トリプロピレングリコールなどのトリアルキレングリコール類、グリセリンなどの多価アルコールが挙げられる。  Examples of the liquid reducing agent include lower alcohols such as methanol, ethanol and isopropanol, alkylene glycols such as ethylene glycol and propylene glycol, dialkylene glycols such as diethylene glycol and dipropylene glycol, and trialkylenes such as triethylene glycol and tripropylene glycol. Examples include polyhydric alcohols such as glycols and glycerin.

Pd化合物、Ru化合物としては、以下のものが挙げられる:
Pd: K2PdCl4, Na2PdCl4, K2PdBr4, Na2PdBr4、硝酸パラジウムなど、
Ru: RuCl3, RuBr3などのハロゲン化ルテニウム、硝酸ルテニウムなど。
Pd compounds and Ru compounds include the following:
Pd: K 2 PdCl 4 , Na 2 PdCl 4 , K 2 PdBr 4 , Na 2 PdBr 4 , palladium nitrate, etc.
Ru: Ruthenium halides such as RuCl 3 and RuBr 3 and ruthenium nitrate.

fcc構造を多く含む原料のPdRu固溶体ナノ粒子は、水素雰囲気、不活性雰囲気もしくは真空中で加熱することにより、fccをhcpに変換することができる。fccをhcpに変換するための反応は、好ましくは水素雰囲気で行われる。水素と不活性ガスを含む雰囲気で反応を行ってもよい。不活性雰囲気に使用する不活性ガスとしては、窒素、アルゴン、ヘリウム、ネオンが挙げられ、窒素又はアルゴンが好ましい。水素雰囲気又は不活性雰囲気の反応圧力は、100〜1000000 Pa程度、より好ましくは1000〜1000000 Pa程度である。反応温度は、好ましくは200〜600℃程度であり、より好ましくは250〜550℃程度であり、さらに好ましくは300〜500℃程度である。反応時間は、5分程度以上、好ましくは30分〜3時間程度である。fccからhcpへの結晶構造の変換は時間とともに進行し、x<0.7の場合には、反応を長時間行うことで結晶構造を100% hcpに変換することができる。  By heating the raw PdRu solid solution nanoparticles containing a large amount of the fcc structure in a hydrogen atmosphere, an inert atmosphere, or a vacuum, fcc can be converted to hcp. The reaction for converting fcc to hcp is preferably performed in a hydrogen atmosphere. The reaction may be performed in an atmosphere containing hydrogen and an inert gas. Examples of the inert gas used in the inert atmosphere include nitrogen, argon, helium, and neon, and nitrogen or argon is preferable. The reaction pressure in a hydrogen atmosphere or an inert atmosphere is about 100 to 100,000 Pa, more preferably about 1,000 to 100,000 Pa. The reaction temperature is preferably about 200 to 600 ° C, more preferably about 250 to 550 ° C, and still more preferably about 300 to 500 ° C. The reaction time is about 5 minutes or more, preferably about 30 minutes to 3 hours. The conversion of the crystal structure from fcc to hcp progresses with time. When x <0.7, the crystal structure can be converted to 100% hcp by performing the reaction for a long time.

(2)第2発明
第2の好ましい実施形態において、本発明は、PtRu固溶体ナノ粒子の結晶構造における六方最密構造(hcp)と面心立方格子(fcc)の割合を制御する方法に関し、液体還元剤を含む加熱溶液にPt化合物とRu化合物を含む溶液を添加する工程において、反応温度を制御することによりhcpとfccの割合を制御することができる。反応終了後に放冷し、遠心分離することにより、六方最密構造(hcp)と面心立方格子(fcc)の割合が制御されたPtRu固溶体ナノ粒子を得ることができる。
(2) Second invention In a second preferred embodiment, the present invention relates to a method for controlling the ratio of the hexagonal close-packed structure (hcp) and the face-centered cubic lattice (fcc) in the crystal structure of PtRu solid solution nanoparticles, In the step of adding the solution containing the Pt compound and the Ru compound to the heating solution containing the reducing agent, the ratio between hcp and fcc can be controlled by controlling the reaction temperature. After cooling, the mixture is allowed to cool and centrifuged to obtain PtRu solid solution nanoparticles in which the ratio of the hexagonal close-packed structure (hcp) and the face-centered cubic lattice (fcc) is controlled.

式PtyRu1-yにおいて、好ましくは0.05≦y≦0.3、より好ましくは0.1≦y≦0.2である。In the formula Pt y Ru 1-y , preferably 0.05 ≦ y ≦ 0.3, more preferably 0.1 ≦ y ≦ 0.2.

Pt化合物、Ru化合物としては、以下のものが挙げられる:
Pt: K2PtCl4、(NH4)2K2PtCl4、(NH4)2PtCl6、Na2PtCl6など、ビスアセチルアセトナト白金(II)、
Ru: RuCl3, RuBr3などのハロゲン化ルテニウム、硝酸ルテニウムなど。
Pt compounds and Ru compounds include the following:
Pt: K 2 PtCl 4 , (NH 4 ) 2 K 2 PtCl 4 , (NH 4 ) 2 PtCl 6 , Na 2 PtCl 6, etc., bisacetylacetonato platinum (II),
Ru: Ruthenium halides such as RuCl 3 and RuBr 3 and ruthenium nitrate.

本発明において、Pt化合物、Ru化合物の還元温度を以下の表に示す。  In the present invention, the reduction temperatures of Pt compounds and Ru compounds are shown in the following table.

Figure 2018159644
Figure 2018159644

反応温度は、好ましくは150〜300℃程度であり、より好ましくは170〜270℃程度であり、さらに好ましくは200〜250℃程度である。反応時間は、5分程度以上、好ましくは10分〜2時間程度である。  The reaction temperature is preferably about 150 to 300 ° C, more preferably about 170 to 270 ° C, and still more preferably about 200 to 250 ° C. The reaction time is about 5 minutes or more, preferably about 10 minutes to 2 hours.

第2発明において、好ましくはPt化合物の還元温度はRu化合物の還元温度よりも5℃以上高く、より好ましくはPt化合物の還元温度はRu化合物の還元温度よりも10℃以上高く、さらに好ましくはPt化合物の還元温度はRu化合物の還元温度よりも15℃以上高い。  In the second invention, the reduction temperature of the Pt compound is preferably 5 ° C. or higher than the reduction temperature of the Ru compound, more preferably the reduction temperature of the Pt compound is 10 ° C. or higher than the reduction temperature of the Ru compound, and further preferably Pt compound The reduction temperature of the compound is at least 15 ° C. higher than the reduction temperature of the Ru compound.

第2発明において、液体還元剤の加熱温度が維持されるように、Pt化合物とRu化合物を含む溶液を液体還元剤の溶液に徐々に添加することが好ましい。添加の方法は、噴霧、滴下、ポンプによる送液などが挙げられる。  In the second invention, it is preferable that the solution containing the Pt compound and the Ru compound is gradually added to the solution of the liquid reducing agent so that the heating temperature of the liquid reducing agent is maintained. Examples of the method of addition include spraying, dropping, and liquid sending by a pump.

Pt化合物とRu化合物を含む溶液を液体還元剤の加熱溶液に添加しても温度はほとんど低下しないので、液体還元剤の加熱温度は反応温度にほぼ等しい。  Even when a solution containing a Pt compound and a Ru compound is added to a heated solution of a liquid reducing agent, the temperature hardly decreases, so that the heating temperature of the liquid reducing agent is substantially equal to the reaction temperature.

hcpが主構造の式PtyRu1-y(0.05≦y≦0.3)で表されるPtRu固溶体ナノ粒子を得る場合、反応温度(すなわち還元剤溶液の温度)はPt化合物の還元温度〜前記還元温度+15℃であることが好ましく、より好ましくはPt化合物とRu化合物の高い方の還元温度〜前記還元温度+10℃であり、さらに好ましくはPt化合物とRu化合物の高い方の還元温度〜前記還元温度+5℃である。反応温度はPt化合物の還元温度と同じか少し高いが、Ru化合物の還元温度よりも十分高いため、Ru化合物の還元のタイミングが少し早くなり、それによりhcpリッチな結晶構造になる。Ru化合物の還元のタイミングは少し早いが、Pt化合物の還元も同時に生じているので、固溶体が得られる。Ru化合物の還元のタイミングが大幅に早いと固溶体は形成されない。固溶体であり、かつ、hcpリッチなPtRu固溶体ナノ粒子を得るためには、温度の微妙な制御が必要とされる。When obtaining a PtRu solid solution nanoparticle in which hcp is represented by the formula Pt y Ru 1-y (0.05 ≦ y ≦ 0.3), the reaction temperature (that is, the temperature of the reducing agent solution) is from the reduction temperature of the Pt compound to the reduction temperature. The temperature is preferably + 15 ° C, more preferably the higher reduction temperature of the Pt compound and the Ru compound to the reduction temperature + 10 ° C, and still more preferably the higher reduction temperature of the Pt compound and the Ru compound to the reduction temperature. + 5 ° C. The reaction temperature is the same as or slightly higher than the reduction temperature of the Pt compound, but is sufficiently higher than the reduction temperature of the Ru compound, so that the timing of the reduction of the Ru compound is slightly advanced, thereby forming an hcp-rich crystal structure. Although the timing of the reduction of the Ru compound is slightly earlier, the reduction of the Pt compound also occurs at the same time, so that a solid solution is obtained. If the timing of the reduction of the Ru compound is much earlier, no solid solution is formed. To obtain hcp-rich PtRu solid solution nanoparticles that are solid solution, delicate control of temperature is required.

fccが主構造の式PtyRu1-y(0.05≦y≦0.3)で表されるPtRu固溶体ナノ粒子を得る場合、反応温度(すなわち還元剤溶液の温度)はPt化合物の還元温度よりも好ましくは15℃よりも高く、より好ましくは20℃以上高く、さらに好ましくは25℃以上高い。反応温度がPt化合物の還元温度よりも十分高いと、Pt化合物の還元のタイミングが少し早くなり、それによりfccリッチな結晶構造になる。Pt化合物の還元のタイミングが大幅に早いと固溶体は形成されない。固溶体であり、かつ、hcpリッチなPtRu固溶体ナノ粒子を得るためには、温度の微妙な制御が必要とされる。When fcc has PtRu solid solution nanoparticles represented by the formula Pt y Ru 1-y (0.05 ≦ y ≦ 0.3) having a main structure, the reaction temperature (that is, the temperature of the reducing agent solution) is more preferable than the reduction temperature of the Pt compound. Is higher than 15 ° C., more preferably higher than 20 ° C., even more preferably higher than 25 ° C. If the reaction temperature is sufficiently higher than the reduction temperature of the Pt compound, the timing of the reduction of the Pt compound becomes slightly earlier, thereby resulting in an fcc-rich crystal structure. If the timing of the reduction of the Pt compound is much earlier, no solid solution is formed. To obtain hcp-rich PtRu solid solution nanoparticles that are solid solution, delicate control of temperature is required.

好ましいPt化合物は、Pt(acac)2、C10H8Cl2N2Ptであり、好ましいRu化合物は、RuCl3である。Preferred Pt compounds are Pt (acac) a 2, C 10 H 8 Cl 2 N 2 Pt, preferably Ru compound is RuCl 3.

例えばPt化合物としてPt(acac)2(還元温度220℃)を使用し、Ru化合物としてRuCl3(還元温度198℃)を使用した場合、反応温度が220℃又は少し温度が高い場合、Pt(acac)2の還元反応は僅かに遅く、RuCl3の還元反応は僅かに早くなり、Ru単体の結晶構造であるhcpが主構造になる。反応温度が220℃よりも十分高い(15℃以上高い、20℃以上高い、25℃以上高い)場合、Pt(acac)2の還元反応が僅かに早くなり、RuCl3の還元反応は僅かに遅くなるため、Pt単体の結晶構造であるfccが主構造になる。還元反応は加圧下に行ってもよい。For example, when using Pt (acac) 2 (reduction temperature 220 ° C.) as a Pt compound and using RuCl 3 (reduction temperature 198 ° C.) as a Ru compound, if the reaction temperature is 220 ° C. or slightly higher, Pt (acac 2 ) The reduction reaction of 2 is slightly slower, the reduction reaction of RuCl 3 is slightly faster, and the main structure is hcp, which is the crystal structure of Ru alone. When the reaction temperature is sufficiently higher than 220 ° C. (15 ° C. or higher, 20 ° C. or higher, 25 ° C. or higher), the reduction reaction of Pt (acac) 2 is slightly faster, and the reduction reaction of RuCl 3 is slightly slower. Therefore, fcc, which is the crystal structure of Pt alone, becomes the main structure. The reduction reaction may be performed under pressure.

液体還元剤としては、メタノール、エタノール、イソプロパノールなどの低級アルコール、エチレングリコール、プロピレングリコールなどのアルキレングリコール類、ジエチレングリコール、ジプロピレングリコールなどのジアルキレングリコール類、トリエチレングリコール、トリプロピレングリコールなどのトリアルキレングリコール類、グリセリンなどの多価アルコールが挙げられる。  Examples of the liquid reducing agent include lower alcohols such as methanol, ethanol and isopropanol, alkylene glycols such as ethylene glycol and propylene glycol, dialkylene glycols such as diethylene glycol and dipropylene glycol, and trialkylenes such as triethylene glycol and tripropylene glycol. Examples include polyhydric alcohols such as glycols and glycerin.

液体還元剤とPt化合物、Ru化合物の反応を担体の存在下に行うと、担体に担持されたPtRu固溶体ナノ粒子が得られる。また、液体還元剤とPt化合物、Ru化合物の反応を表面保護剤の存在下に行うと、表面保護剤で被覆されたPtRu固溶体ナノ粒子が得られる。  When the reaction between the liquid reducing agent and the Pt compound or Ru compound is performed in the presence of a carrier, PtRu solid solution nanoparticles supported on the carrier are obtained. When the liquid reducing agent is reacted with the Pt compound and the Ru compound in the presence of a surface protective agent, PtRu solid solution nanoparticles coated with the surface protective agent are obtained.

担体は特に制限はないが、具体的には酸化物類、窒化物類、炭化物類、カーボン、単体金属などが担体として挙げられ、中でも酸化物類、カーボンが好ましい。酸化物類としては、シリカ、アルミナ、セリア、チタニア、ジルコニア、ニオビアなどの酸化物や、シリカ−アルミナ、チタニア−ジルコニア、セリア−ジルコニア、チタン酸ストロンチウムなどの複合酸化物などが挙げられる。カーボンとしては、活性炭、カーボンブラック、グラファイト、カーボンナノチューブ、活性炭素繊維などが挙げられる。窒化物類としては、窒化ホウ素、窒化ケイ素、窒化ガリウム、窒化インジウム、窒化アルミニウム、窒化ジルコニウム、窒化バナジウム、窒化タングステン、窒化モリブデン、窒化チタン、窒化ニオブが挙げられる。炭化物類としては、炭化ケイ素、炭化ガリウム、炭化インジウム、炭化アルミニウム、炭化ジルコニウム、炭化バナジウム、炭化タングステン、炭化モリブデン、炭化チタン、炭化ニオブ、炭化ホウ素が挙げられる。単体金属としては、鉄、銅、アルミニウムなどの純金属及びステンレスなどの合金が挙げられる。  The carrier is not particularly limited, but specific examples thereof include oxides, nitrides, carbides, carbon, and simple metals. Among them, oxides and carbon are preferable. Examples of the oxides include oxides such as silica, alumina, ceria, titania, zirconia, and niobium, and composite oxides such as silica-alumina, titania-zirconia, ceria-zirconia, and strontium titanate. Examples of the carbon include activated carbon, carbon black, graphite, carbon nanotube, and activated carbon fiber. Examples of the nitrides include boron nitride, silicon nitride, gallium nitride, indium nitride, aluminum nitride, zirconium nitride, vanadium nitride, tungsten nitride, molybdenum nitride, titanium nitride, and niobium nitride. Examples of the carbides include silicon carbide, gallium carbide, indium carbide, aluminum carbide, zirconium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, titanium carbide, niobium carbide, and boron carbide. Examples of the simple metal include pure metals such as iron, copper, and aluminum and alloys such as stainless steel.

本発明のPtRu固溶体ナノ粒子は、表面保護剤により被覆されていてもよい。表面保護剤としては、ポリビニルピロリドン(PVP)、ポリエチレングリコール(PEG)などのポリマー類、オレイルアミンなどのアミン類、オレイン酸などのカルボン酸類が挙げられる。  The PtRu solid solution nanoparticles of the present invention may be coated with a surface protective agent. Examples of the surface protective agent include polymers such as polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG), amines such as oleylamine, and carboxylic acids such as oleic acid.

本発明のPtRu固溶体ナノ粒子は、メタノール酸化用触媒、水添反応用触媒、水素酸化反応用触媒、酸素還元反応(ORR)用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒、水素燃料電池用触媒、炭化水素の酸化反応用触媒として優れており、メタノール酸化用触媒、水電解反応用触媒、三元触媒などの排ガス浄化触媒として好ましく使用される。三元触媒の場合、例えばNOxは窒素に還元され、COは二酸化炭素に酸化され、炭化水素(CH)は水と二酸化炭素に酸化される。  The PtRu solid solution nanoparticles of the present invention are a catalyst for methanol oxidation, a catalyst for hydrogenation reaction, a catalyst for hydrogen oxidation reaction, a catalyst for oxygen reduction reaction (ORR), a catalyst for oxygen generation reaction (OER), and a hydrogen generation reaction (HER). Catalyst, nitrogen oxide (NOx) reduction reaction catalyst, carbon monoxide (CO) oxidation reaction catalyst, dehydrogenation reaction catalyst, VVOC or VOC oxidation reaction catalyst, exhaust gas purification catalyst, water electrolysis catalyst, It is excellent as a catalyst for hydrogen fuel cells and a catalyst for oxidation reactions of hydrocarbons, and is preferably used as an exhaust gas purification catalyst such as a catalyst for methanol oxidation, a catalyst for water electrolysis reaction, and a three-way catalyst. In the case of a three-way catalyst, for example, NOx is reduced to nitrogen, CO is oxidized to carbon dioxide, and hydrocarbons (CH) are oxidized to water and carbon dioxide.

(第3発明)
第3発明で得られる固溶体ナノ粒子は、式AuzRu1-z(0.05≦z≦0.4)で表わされる、 AuとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)又は面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子である。本発明では、AuとRuの比率が同一であり、かつ、結晶構造の主構造がhcp又はfccであるAuRu固溶体ナノ粒子が得られる。
(Third invention)
The solid solution nanoparticles obtained by the third invention are represented by the formula Au z Ru 1-z (0.05 ≦ z ≦ 0.4), in which Au and Ru form a solid solution at the atomic level, and the main structure is a hexagonal close-packed structure ( hcp) or AuRu solid solution nanoparticles with face-centered cubic lattice structure (fcc). According to the present invention, AuRu solid solution nanoparticles having the same ratio of Au to Ru and having a main crystal structure of hcp or fcc are obtained.

ここで、「AuRu固溶体ナノ粒子」とは、ナノ粒子の中でAuとRuが均一に存在し、各金属原子の分布に偏りがないことを意味する。  Here, “AuRu solid solution nanoparticles” mean that Au and Ru are uniformly present in the nanoparticles and that the distribution of each metal atom is not biased.

本発明の固溶体ナノ粒子において、zは、0.05≦z≦0.4、好ましくは0.1≦z≦0.35、より好ましくは0.15≦z≦0.25である。  In the solid solution nanoparticles of the present invention, z is 0.05 ≦ z ≦ 0.4, preferably 0.1 ≦ z ≦ 0.35, and more preferably 0.15 ≦ z ≦ 0.25.

本発明のAuRu固溶体ナノ粒子の平均粒径は、1〜100 nm程度、好ましくは1〜50 nm程度、より好ましくは1〜10 nm程度、さらに好ましくは1〜6 nm程度である。平均粒径が小さいと触媒性能が高くなるために好ましい。固溶体ナノ粒子の平均粒径は、TEMなどの顕微鏡写真により確認することができる。固溶体ナノ粒子の形状は特に限定されず、球状、楕円体状、ロッド状、柱状、リン片状など任意の形状であってよい。  The average particle size of the AuRu solid solution nanoparticles of the present invention is about 1 to 100 nm, preferably about 1 to 50 nm, more preferably about 1 to 10 nm, and still more preferably about 1 to 6 nm. It is preferable that the average particle size is small because the catalyst performance becomes high. The average particle size of the solid solution nanoparticles can be confirmed by a micrograph such as a TEM. The shape of the solid solution nanoparticles is not particularly limited, and may be any shape such as a sphere, an ellipsoid, a rod, a column, and a scale.

本発明の固溶体ナノ粒子の製造方法は、Au化合物とRu化合物の溶媒溶液、還元剤と表面保護剤の溶媒溶液を調製し、Au化合物とRu化合物の溶媒溶液を還元剤と表面保護剤(任意成分)の溶媒溶液にスプレー、滴下、ポンプによる送液等で少量ずつ添加することにより得ることができる。  The method for producing the solid solution nanoparticles of the present invention comprises preparing a solvent solution of an Au compound and a Ru compound, a solvent solution of a reducing agent and a surface protecting agent, and converting the solvent solution of the Au compound and the Ru compound into a reducing agent and a surface protecting agent (optionally). It can be obtained by adding a small amount to the solvent solution of the component (1) by spraying, dropping, sending liquid by a pump, or the like.

本発明のAuRu固溶体ナノ粒子は、例えば、Au化合物とRu化合物を含む溶媒溶液と液体還元剤を準備し、液体還元剤にAu化合物とRu化合物を含む溶媒溶液を加えて加熱下(例えば150〜300℃程度)に1分〜12時間程度撹拌下に反応し、その後に放冷し、遠心分離することにより、主構造がfccであるAuRu固溶体ナノ粒子を得ることができる。液体還元剤とAu化合物、Ru化合物の反応を担体の存在下に行うと、担体に担持されfcc構造を多く含むAuRu固溶体ナノ粒子が得られる。液体還元剤とAu化合物、Ru化合物の反応を表面保護剤の存在下に行うと、ナノ粒子表面が表面保護剤で被覆されたAuRu固溶体ナノ粒子が得られる。表面保護剤を使用しない場合、精製したナノ粒子は凝集物として得られる。   The AuRu solid solution nanoparticles of the present invention may be prepared, for example, by preparing a solvent solution containing an Au compound and a Ru compound and a liquid reducing agent, adding a solvent solution containing the Au compound and the Ru compound to the liquid reducing agent, and heating (for example, 150 to (Roughly 300 ° C.) for about 1 minute to 12 hours under stirring, then allowed to cool, and centrifuged to obtain AuRu solid solution nanoparticles having a main structure of fcc. When the reaction between the liquid reducing agent and the Au compound or Ru compound is carried out in the presence of a carrier, AuRu solid solution nanoparticles supported on the carrier and containing a large number of fcc structures are obtained. When the reaction between the liquid reducing agent and the Au compound or Ru compound is performed in the presence of a surface protective agent, AuRu solid solution nanoparticles having the nanoparticle surface coated with the surface protective agent are obtained. If no surface protective agent is used, the purified nanoparticles are obtained as aggregates.

反応系内にCTAB(Cetyl trimethyl ammonium bromide)を加えると、Auの還元速度が下がり、Ruが僅かに早く還元されるので、主構造がhcpであるAuRu固溶体ナノ粒子(担体に担持されていてもよく、表面保護剤で被覆されていてもよい)が得られる。  When CTAB (Cetyl trimethyl ammonium bromide) is added into the reaction system, the reduction rate of Au is reduced and Ru is reduced slightly faster, so that the main structure is AuRu solid solution nanoparticles having hcp (even if supported on a carrier). And may be coated with a surface protective agent).

CTABの反応系における濃度は、金属塩の濃度に対して好ましくは1/10倍〜100倍程度、より好ましくは1倍〜30倍程度である。  The concentration of CTAB in the reaction system is preferably about 1/10 to 100 times, more preferably about 1 to 30 times the concentration of the metal salt.

溶媒としては、水、アルコール(メタノール、エタノール、イソプロパノールなど)、ポリオール類(エチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレンングリコール、グリセリンなど)、ポリエーテル類(ポリエチレングリコールなど)などが使用でき、1種単独で又は2種以上を組み合わせて使用することができる。溶媒としては、水、アルコール又は含水アルコールが好ましい。  Examples of the solvent include water, alcohols (eg, methanol, ethanol, isopropanol), polyols (eg, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and glycerin), and polyethers (eg, polyethylene glycol). These can be used alone or in combination of two or more. As the solvent, water, alcohol or hydrated alcohol is preferable.

反応温度は、好ましくは150〜300℃程度であり、より好ましくは170〜270℃程度であり、さらに好ましくは200〜250℃程度である。反応時間は、5分程度以上、好ましくは10分〜2時間程度である。  The reaction temperature is preferably about 150 to 300 ° C, more preferably about 170 to 270 ° C, and still more preferably about 200 to 250 ° C. The reaction time is about 5 minutes or more, preferably about 10 minutes to 2 hours.

Au化合物とRu化合物は、水溶性であることが好ましく、塩であることがより好ましい。好ましいAu化合物とRu化合物としては、硫酸塩、硝酸塩、酢酸塩などの有機酸塩、炭酸塩、ハロゲン化物(フッ化物、塩化物、臭化物、ヨウ化物)などが挙げられ、ハロゲン化物、酢酸塩等の有機酸塩、硝酸塩が好ましく使用できる。Auは、2価、3価、4価のいずれでもよい。Ruは1価、2価、3価、4価のいずれでもよい。  The Au compound and the Ru compound are preferably water-soluble, and are more preferably salts. Preferred Au compounds and Ru compounds include organic acid salts such as sulfates, nitrates, and acetates, carbonates, and halides (fluoride, chloride, bromide, and iodide), and halides, acetates, and the like. Organic acid salts and nitrates can be preferably used. Au may be divalent, trivalent, or tetravalent. Ru may be monovalent, divalent, trivalent, or tetravalent.

Au化合物、Ru化合物としては、以下のものが挙げられる:
Au: HAuCl4、HAuBr4、K2AuCl6、Na2AuCl6、酢酸金など、
Ru: RuCl3, RuBr3などのハロゲン化ルテニウム、硝酸ルテニウムなど。
Au化合物とRu化合物の溶媒溶液中の濃度としては、各々0.01〜1000mmol/L程度、好ましくは0.05〜100 mmol/L 程度、より好ましくは0.1〜50 mmol/L程度である。Au化合物とRu化合物の濃度が濃すぎるとAuとRuの原子レベルで均一性が低下する可能性がある。還元反応は加圧下に行ってもよい。
The Au compound and the Ru compound include the following:
Au: HAuCl 4 , HAuBr 4 , K 2 AuCl 6 , Na 2 AuCl 6 , gold acetate, etc.
Ru: Ruthenium halides such as RuCl 3 and RuBr 3 and ruthenium nitrate.
The concentration of the Au compound and the Ru compound in the solvent solution is about 0.01 to 1000 mmol / L, preferably about 0.05 to 100 mmol / L, and more preferably about 0.1 to 50 mmol / L. If the concentrations of the Au compound and the Ru compound are too high, the uniformity may be reduced at the atomic level of Au and Ru. The reduction reaction may be performed under pressure.

液体還元剤としては、メタノール、エタノール、イソプロパノールなどの低級アルコール、エチレングリコール、プロピレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール等のグリコール類、グリセリン、ジグリセリン、トリグリセリン、デカグリセリンなどのポリグリセリン、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテルなどのアルキレングリコールモノアルキルエーテル、ブチルアミン、ドデシルアミン、オレイルアミンなどのアミン類、オレイン酸、リノール酸、リノレン酸などの不飽和脂肪酸、ドデセン、テトラデセン、オクタデセンなどの不飽和炭化水素、NaBH4、LiBH4、NaCNBH3、LiAlH4などが使用できる。  Examples of the liquid reducing agent include lower alcohols such as methanol, ethanol, and isopropanol; glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol; and polyglycerins such as glycerin, diglycerin, triglycerin, and decaglycerin. Alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; amines such as butylamine, dodecylamine and oleylamine; and oleic acid, linoleic acid and linolenic acid. Saturated fatty acids, unsaturated hydrocarbons such as dodecene, tetradecene and octadecene, NaBH 4, LiBH4, NaCNBH3, LiAlH4, etc. can be used.

表面保護剤としては、ポリビニルピロリドン(PVP)、ポリエチレングリコール(PEG)などのポリマー類、オレイルアミンなどのアミン類、オレイン酸などのカルボン酸類が使用できる。  As the surface protective agent, polymers such as polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG), amines such as oleylamine, and carboxylic acids such as oleic acid can be used.

担体としては、特に制限はないが、具体的には酸化物類、窒化物類、炭化物類、単体炭素、単体金属などが担体として挙げられ、中でも酸化物類、単体炭素が好ましく、酸化物類が特に好ましい担体である。酸化物類としては、シリカ、アルミナ、セリア、チタニア、ジルコニア、ニオビアなどの酸化物や、シリカ−アルミナ、チタニア−ジルコニア、セリア−ジルコニア、チタン酸ストロンチウムなどの複合酸化物などが挙げられる。単体炭素としては、活性炭、カーボンブラック、グラファイト、カーボンナノチューブ、活性炭素繊維などが挙げられる。窒化物類としては、窒化ホウ素、窒化ケイ素、窒化ガリウム、窒化インジウム、窒化アルミニウム、窒化ジルコニウム、窒化バナジウム、窒化タングステン、窒化モリブデン、窒化チタン、窒化ニオブが挙げられる。炭化物類としては、炭化ケイ素、炭化ガリウム、炭化インジウム、炭化アルミニウム、炭化ジルコニウム、炭化バナジウム、炭化タングステン、炭化モリブデン、炭化チタン、炭化ニオブ、炭化ホウ素が挙げられる。単体金属としては、鉄、銅、アルミニウムなどの純金属及びステンレスなどの合金が挙げられる。  The carrier is not particularly limited, and specific examples thereof include oxides, nitrides, carbides, simple carbon, and simple metals. Among them, oxides and simple carbon are preferable, and oxides are preferable. Is a particularly preferred carrier. Examples of the oxides include oxides such as silica, alumina, ceria, titania, zirconia, and niobium, and composite oxides such as silica-alumina, titania-zirconia, ceria-zirconia, and strontium titanate. Examples of the simple carbon include activated carbon, carbon black, graphite, carbon nanotube, and activated carbon fiber. Examples of the nitrides include boron nitride, silicon nitride, gallium nitride, indium nitride, aluminum nitride, zirconium nitride, vanadium nitride, tungsten nitride, molybdenum nitride, titanium nitride, and niobium nitride. Examples of the carbides include silicon carbide, gallium carbide, indium carbide, aluminum carbide, zirconium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, titanium carbide, niobium carbide, and boron carbide. Examples of the simple metal include pure metals such as iron, copper, and aluminum and alloys such as stainless steel.

本発明のAuRu固溶体ナノ粒子は、水添反応用触媒、水素酸化反応用触媒、酸素還元反応(ORR)用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒、水素燃料電池用触媒、炭化水素の酸化反応用触媒として優れており、水電解反応用触媒、三元触媒などの排ガス浄化触媒として好ましく使用される。三元触媒の場合、例えばNOxは窒素に還元され、COは二酸化炭素に酸化され、炭化水素(CH)は水と二酸化炭素に酸化される。  The AuRu solid solution nanoparticles of the present invention include a catalyst for hydrogenation reaction, a catalyst for hydrogen oxidation reaction, a catalyst for oxygen reduction reaction (ORR), a catalyst for oxygen evolution reaction (OER), a catalyst for hydrogen evolution reaction (HER), and nitrogen oxidation catalyst. (NOx) reduction catalyst, carbon monoxide (CO) oxidation reaction catalyst, dehydrogenation catalyst, VVOC or VOC oxidation reaction catalyst, exhaust gas purification catalyst, water electrolysis catalyst, hydrogen fuel cell catalyst It is excellent as a catalyst for hydrocarbon oxidation reaction, and is preferably used as a catalyst for exhaust gas purification such as a catalyst for water electrolysis reaction and a three-way catalyst. In the case of a three-way catalyst, for example, NOx is reduced to nitrogen, CO is oxidized to carbon dioxide, and hydrocarbons (CH) are oxidized to water and carbon dioxide.

以下、本発明を実施例に基づきより詳細に説明するが、本発明がこれら実施例に限定されないことはいうまでもない。  Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

実施例において、以下の装置を用いた。
(i)Powder X-ray Diffraction (PXRD)
SPring8 BL02B2 (λ = 0.58 Å, in-situ measurement)
Bruker D8 Advance (Cu Kα = 1.54 Å)
(ii)Transmission electron microscope (TEM)
Hitachi HT7700 (accelerating voltage: 100 kV)
(iii)High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM)
JEOL JEM-ARM200F (accelerating voltage: 200 kV)
(iv)X-ray photoelectron spectroscopy (XPS)
Shimadzu ECSA-3400 (The data were calibrated by carbon 1s signal )
(v)Electrocatalytic process
ALS CHI electrochemical analyzer Model 760E
Rotating Ring Disk Electrode RRDE-3A (ALS Japan)
In the examples, the following devices were used.
(i) Powder X-ray Diffraction (PXRD)
SPring8 BL02B2 (λ = 0.58 Å, in-situ measurement)
Bruker D8 Advance (Cu Kα = 1.54 Å)
(ii) Transmission electron microscope (TEM)
Hitachi HT7700 (accelerating voltage: 100 kV)
(iii) High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM)
JEOL JEM-ARM200F (accelerating voltage: 200 kV)
(iv) X-ray photoelectron spectroscopy (XPS)
Shimadzu ECSA-3400 (The data were calibrated by carbon 1s signal)
(v) Electrocatalytic process
ALS CHI electrochemical analyzer Model 760E
Rotating Ring Disk Electrode RRDE-3A (ALS Japan)

参考例1−2:PdRu固溶体ナノ粒子の製造(Pd:Ru=4:6、5:5)
トリエチレングリコール300 mlを200 ℃で加熱撹拌する。この加熱混合物にK2PdCl4(0.4 mmol又は0.5 mmol)とRuCl3(0.6 mmol又は0.5 mmol)をイオン交換水40 mlに溶かした溶液を加え、 200 ℃で10分間維持した後放冷し、生じた沈殿物を遠心分離により分離した。fccが主構造であるPd0.4Ru0.6固溶体ナノ粒子(参考例1) 及びPd0.5Ru0.5固溶体ナノ粒子(参考例2)を得た。
Reference Example 1-2: Production of PdRu solid solution nanoparticles (Pd: Ru = 4: 6, 5: 5)
Heat and stir 300 ml of triethylene glycol at 200 ° C. To this heated mixture was added a solution of K 2 PdCl 4 (0.4 mmol or 0.5 mmol) and RuCl 3 (0.6 mmol or 0.5 mmol) dissolved in 40 ml of ion-exchanged water. The mixture was maintained at 200 ° C. for 10 minutes, and then allowed to cool. The resulting precipitate was separated by centrifugation. Pd 0.4 Ru 0.6 solid solution nanoparticles having a main structure of fcc (Reference Example 1) and Pd 0.5 Ru 0.5 solid solution nanoparticles (Reference Example 2) were obtained.

実施例1
参考例1で得たPd0.4Ru0.6固溶体ナノ粒子(平均粒径13.2nm)を1気圧の水素雰囲気下に573K(300℃)で35分、41分、47分又は53分間加熱し、PXRDを行った。結果を図1(53分間)、図2に示す。図1には、水素雰囲気に代えて真空中で反応させたもの(Vac-treated)、Pdバルク、参考例1で得たPd0.4Ru0.6固溶体ナノ粒子(As-synthesized)を合わせて示す。
Example 1
The Pd 0.4 Ru 0.6 solid solution nanoparticles (average particle diameter 13.2 nm) obtained in Reference Example 1 were heated at 573 K (300 ° C.) for 35 minutes, 41 minutes, 47 minutes, or 53 minutes in a hydrogen atmosphere at 1 atm, and PXRD was measured. went. The results are shown in FIG. 1 (53 minutes) and FIG. FIG. 1 also shows the reaction in vacuum (Vac-treated), the Pd bulk, and the Pd 0.4 Ru 0.6 solid solution nanoparticles (As-synthesized) obtained in Reference Example 1 in place of the hydrogen atmosphere.

さらに、実施例1(30分間300℃処理)のPd0.4Ru0.6固溶体ナノ粒子とカーボン (Vulcan XC-72R, Cobalt Co.) の混合物 (金属含有量20 wt.% )を水と2−プロパノールの混合液(1:5 v/v)中、4時間室温で超音波処理し、遠心分離してカーボン担持Pd0.4Ru0.6固溶体ナノ粒子を遠心処理により回収し、真空中で乾燥し、TEM像(図3)、PXRDパターン(図4)、HAADF-STEM像(図5)を得た。Further, a mixture (metal content: 20 wt.%) Of Pd 0.4 Ru 0.6 solid solution nanoparticles of Example 1 (treated at 300 ° C. for 30 minutes) and carbon (Vulcan XC-72R, Cobalt Co.) was mixed with water and 2-propanol. In a mixed solution (1: 5 v / v), sonication was performed at room temperature for 4 hours, followed by centrifugation to collect the Pd 0.4 Ru 0.6 solid solution nanoparticles supported on carbon by centrifugation, drying in vacuum, and TEM image ( FIG. 3), PXRD pattern (FIG. 4), and HAADF-STEM image (FIG. 5) were obtained.

実施例2
参考例2で得たPd0.5Ru0.5固溶体ナノ粒子(平均粒径10.5nm)を、1気圧の水素雰囲気下に373K(100℃)、473K(200℃)、573K(300℃)、623K(350℃)、673K(400℃)で各5分間加熱し、PXRDを行った。結果を図6に示す。さらに、Pd0.5Ru0.5固溶体ナノ粒子(573Kで処理)のTEM像を得た(図7)。
Example 2
The Pd 0.5 Ru 0.5 solid solution nanoparticles (average particle size 10.5 nm) obtained in Reference Example 2 were 373 K (100 ° C.), 473 K (200 ° C.), 573 K (300 ° C.), 623 K (350 ) And 673K (400 ° C) for 5 minutes each to perform PXRD. FIG. 6 shows the results. Further, a TEM image of Pd 0.5 Ru 0.5 solid solution nanoparticles (treated at 573 K) was obtained (FIG. 7).

試験例1
[電極の製造]
実施例1のhcp構造のPd0.4Ru0.6固溶体ナノ粒子(53分間300℃処理)をカーボン粒子に担持したPdRu固溶体回転リングディスク電極(PdRu/C:金属量20wt%)を製造した。回転リングディスク電極(RDE)の直径は5mmであった。
[OER(酸素発生反応)触媒活性]
電流測定装置:ポテンシオスタット(BAS社製 ALS760E)
測定方法:実施例1のhcp結晶構造のPd0.4Ru0.6固溶体ナノ粒子をカーボンに担持した回転リングディスク電極をアノードとし、3電極式セル(対極:白金線、参照極:銀−塩化銀電極(Ag/AgCl)、電解液:0.1MのHClO、25℃、酸素飽和)を用いて、1Vから2.0V(vs.RHE)まで50mV/sにて電位Eを掃引したときの電流値Iを測定した。比較のために電極材料をhcp結晶構造のPd0.4Ru0.6固溶体ナノ粒子に代えてfcc結晶構造のPd0.4Ru0.6固溶体ナノ粒子、Pdナノ粒子(Pd NPs)、Ruナノ粒子(Ru NPs)を用いて同様にOER触媒活性を測定した。結果を図8に示す。また、電解液として1.0MのNaOHを用い、同様にOER触媒活性を測定した。結果を図9に示す。
[ORR(酸素還元反応) 触媒活性]
電流測定装置:ポテンシオスタット(BAS社製 ALS760E)
測定方法:実施例1のhcp結晶構造のPd0.4Ru0.6固溶体ナノ粒子をカーボン粒子に担持した回転リングディスク電極をカソードとし、3電極式セル(対極:白金線、参照極:水銀−酸化水銀電極(Hg/HgO)、電解液:1.0MのNaOH、25℃、酸素飽和)を用いて、−1Vから0.1V(vs.RHE)まで50mV/sにて電位Eを掃引したときの電流値Iを測定し、ORR触媒活性を評価した。比較のために電極材料をhcp結晶構造のPd0. 4Ru0.6固溶体ナノ粒子に代えてfcc結晶構造のPd0.4Ru0.6固溶体ナノ粒子を用いて同様にカソードを作製し、ORR触媒活性を評価した。結果を図10に示す。
Test example 1
[Production of electrodes]
A PdRu solid solution rotating ring disk electrode (PdRu / C: metal amount: 20 wt%) in which the hcp structure Pd 0.4 Ru 0.6 solid solution nanoparticles (treated at 300 ° C. for 53 minutes) of Example 1 was supported on carbon particles was produced. The diameter of the rotating ring disk electrode (RDE) was 5 mm.
[OER (Oxygen evolution reaction) catalytic activity]
Current measuring device: potentiostat (ALS760E manufactured by BAS)
Measurement method: A three-electrode cell (a counter electrode: a platinum wire, a reference electrode: a silver-silver chloride electrode) was used as an anode, with a rotating ring disk electrode carrying Pd 0.4 Ru 0.6 solid solution nanoparticles having an hcp crystal structure of carbon of Example 1 supported on carbon as an anode. Ag / AgCl), electrolytic solution: 0.1 M HClO 4 , 25 ° C., oxygen saturation), and the current value when the potential E is swept from 1 V to 2.0 V (vs. RHE) at 50 mV / s. I was measured. Pd 0.4 Ru 0.6 solid solution nanoparticles having an fcc crystal structure in place of the electrode material to Pd 0.4 Ru 0.6 solid solution nanoparticles hcp crystal structure for comparison, Pd nanoparticles (Pd NPs), using a Ru nanoparticle (Ru NPs) OER catalytic activity was measured in the same manner. FIG. 8 shows the results. OER catalyst activity was measured in the same manner using 1.0 M NaOH as the electrolyte. The results are shown in FIG.
[ORR (oxygen reduction reaction) catalytic activity]
Current measuring device: potentiostat (ALS760E manufactured by BAS)
Measuring method: Three-electrode cell (counter electrode: platinum wire, reference electrode: mercury-mercury oxide electrode), using a rotating ring disk electrode having carbon particles carrying Pd 0.4 Ru 0.6 solid solution nanoparticles of hcp crystal structure of Example 1 as a cathode (Hg / HgO), current when sweeping the potential E from -1 V to 0.1 V (vs. RHE) at 50 mV / s using an electrolytic solution: 1.0 M NaOH, 25 ° C., oxygen saturation). The value I was measured to evaluate the ORR catalytic activity. To prepare a cathode similarly electrode material for comparison with Pd 0.4 Ru 0.6 solid solution nanoparticles having an fcc crystal structure in place of the Pd 0. 4 Ru 0.6 solid solution nanoparticles hcp crystal structure was evaluated ORR catalytic activity . The results are shown in FIG.

試験例2
実施例1のhcpのPd0.4Ru0.6固溶体ナノ粒子(53分間300℃処理)に代えて実施例2のhcpのPd0.5Ru0.5固溶体ナノ粒子(400℃処理)を用い、試験例1と同様にしてOER触媒活性を測定した。結果を図11に示す。
Test example 2
In the same manner as in Test Example 1, the hcp Pd 0.5 Ru 0.5 solid solution nanoparticles (treated at 400 ° C.) of Example 2 were used instead of the hcp Pd 0.4 Ru 0.6 solid solution nanoparticles (treated at 300 ° C. for 53 minutes) of Example 1. The OER catalytic activity was measured. The results are shown in FIG.

試験例3
実施例1のhcpのPd0.4Ru0.6固溶体ナノ粒子(53分間300℃処理)、参考例1のfccのPd0.4Ru0.6固溶体ナノ粒子を用い、加速耐久性試験(ADT)を行い、試験後のサンプルについてTEM像を得た。結果を図12に示す。
Test example 3
Using the hcp Pd 0.4 Ru 0.6 solid solution nanoparticles of Example 1 (treated at 300 ° C. for 53 minutes) and the fcc Pd 0.4 Ru 0.6 solid solution nanoparticles of Reference Example 1, an accelerated durability test (ADT) was performed. A TEM image was obtained for the sample. The result is shown in FIG.

また、実施例1のhcpのPd0.4Ru0.6固溶体ナノ粒子(53分間300℃処理)、参考例1のfccのPd0.4Ru0.6固溶体ナノ粒子のXPSの測定結果を図13に示す。FIG. 13 shows the XPS measurement results of the hcp Pd 0.4 Ru 0.6 solid solution nanoparticles of Example 1 (treated at 300 ° C. for 53 minutes) and the fcc Pd 0.4 Ru 0.6 solid solution nanoparticles of Reference Example 1.

実施例3、4
トリエチレングリコール(TEG、還元剤) 100ml及び1.0mmol PVP(ポリビニルピロリドン、保護剤)の混合液を220℃(実施例3)又は250℃(実施例4)で加熱撹拌し、この溶液にPt(acac)2(0.04mmol)とRuCl3(0.16mmol)をエタノール10mlに溶かした溶液を滴下し、220℃又は250℃で1時間維持した後放冷し、生じた沈殿物を遠心分離により分離した。分離したPtRu固溶体ナノ粒子について、XRDパターンとTEM画像を得た(図14)。実施例3でhcp構造のPtRu固溶体ナノ粒子が得られ、実施例4でfcc構造のPtRu固溶体ナノ粒子が得られたことが明らかになった。
Examples 3 and 4
A mixture of 100 ml of triethylene glycol (TEG, a reducing agent) and 1.0 mmol of PVP (polyvinylpyrrolidone, a protective agent) was heated and stirred at 220 ° C. (Example 3) or 250 ° C. (Example 4). A solution of acac) 2 (0.04 mmol) and RuCl 3 (0.16 mmol) dissolved in 10 ml of ethanol was added dropwise. The mixture was maintained at 220 ° C. or 250 ° C. for 1 hour, allowed to cool, and the resulting precipitate was separated by centrifugation. . XRD patterns and TEM images were obtained for the separated PtRu solid solution nanoparticles (FIG. 14). Example 3 revealed that PtRu solid solution nanoparticles having the hcp structure were obtained, and Example 4 obtained PtRu solid solution nanoparticles having the fcc structure.

実施例5、6
トリエチレングリコール(TEG、還元剤) 100ml及び1.0mmol PVP(ポリビニルピロリドン、保護剤)の混合液を220℃(実施例5)又は250℃(実施例6)で加熱撹拌し、この溶液にPt(acac)2(0.02mmol)とRuCl3(0.18mmol)をエタノール10mlに溶かした溶液を滴下し、220℃又は250℃で1時間維持した後放冷し、生じた沈殿物を遠心分離により分離した。分離したPtRu固溶体ナノ粒子について、XRDパターンとTEM画像を得た(図15)。実施例5でhcp構造のPtRu固溶体ナノ粒子が得られ、実施例6でfcc構造のPtRu固溶体ナノ粒子が得られたことが明らかになった。
Examples 5 and 6
A mixture of 100 ml of triethylene glycol (TEG, a reducing agent) and 1.0 mmol of PVP (polyvinylpyrrolidone, a protective agent) was heated and stirred at 220 ° C. (Example 5) or 250 ° C. (Example 6). A solution of acac) 2 (0.02 mmol) and RuCl 3 (0.18 mmol) dissolved in 10 ml of ethanol was added dropwise. The mixture was maintained at 220 ° C. or 250 ° C. for 1 hour, allowed to cool, and the resulting precipitate was separated by centrifugation. . XRD patterns and TEM images were obtained for the separated PtRu solid solution nanoparticles (FIG. 15). In Example 5, PtRu solid solution nanoparticles having the hcp structure were obtained, and in Example 6, PtRu solid solution nanoparticles having the fcc structure were obtained.

比較例1
トリエチレングリコール(TEG、還元剤) 100ml及び1.0mmol PVP(ポリビニルピロリドン、保護剤)の混合液を220℃で加熱撹拌し、この溶液にH2PtCl6(0.04mmol)とRuCl3(0.16mmol)をエタノール10mlに溶かした溶液を滴下し、220℃で1時間維持した後放冷し、生じた沈殿物を遠心分離により分離した。分離したPtRu固溶体ナノ粒子について、XRDパターンとTEM画像を得た(図16)。比較例1でfcc構造のPtRu固溶体ナノ粒子が得られたことが明らかになった。
Comparative Example 1
A mixture of 100 ml of triethylene glycol (TEG, a reducing agent) and 1.0 mmol of PVP (polyvinylpyrrolidone, a protective agent) is heated and stirred at 220 ° C., and H 2 PtCl 6 (0.04 mmol) and RuCl 3 (0.16 mmol) are added to the solution. Was dissolved in 10 ml of ethanol, and the mixture was maintained at 220 ° C. for 1 hour, allowed to cool, and the resulting precipitate was separated by centrifugation. XRD patterns and TEM images were obtained for the separated PtRu solid solution nanoparticles (FIG. 16). Comparative Example 1 revealed that PtRu solid solution nanoparticles having an fcc structure were obtained.

実施例7
ジエチレングリコール(DEG、還元剤) 30mlにHAuBr4(0.03 mmol)及びRuCl3(0.07 mmol)を溶解した(以下、「前駆体溶液」という)。
Example 7
HAuBr 4 (0.03 mmol) and RuCl 3 (0.07 mmol) were dissolved in 30 ml of diethylene glycol (DEG, a reducing agent) (hereinafter, referred to as “precursor solution”).

ジエチレングリコール(DEG、還元剤) 100 mlにPVP(4 mmol)及びCTAB(1.5mmol)を加えて撹拌して溶かし、溶液を215℃に加熱した。この溶液の温度を215℃に維持しながら前駆体溶液を0.75ml/minの速度でポンプにより加えた。さらに5分間215℃を維持し、室温まで冷却した。Au0.3Ru0.7固溶体ナノ粒子を沈殿物として遠心分離により回収し、真空下に乾燥した。得られた沈殿物はhcp構造を有する固溶体ナノ粒子であることが粉末X線回折(図17)、TEM像(図18)、HAADF-STEM像およびSTEM-EDXマップ(図19)により確認された。To 100 ml of diethylene glycol (DEG, a reducing agent), PVP (4 mmol) and CTAB (1.5 mmol) were added and dissolved by stirring, and the solution was heated to 215 ° C. The precursor solution was pumped in at a rate of 0.75 ml / min while maintaining the temperature of the solution at 215 ° C. Maintained at 215 ° C. for another 5 minutes and cooled to room temperature. The Au 0.3 Ru 0.7 solid solution nanoparticles were collected as a precipitate by centrifugation and dried under vacuum. The obtained precipitate was confirmed to be solid solution nanoparticles having the hcp structure by powder X-ray diffraction (FIG. 17), TEM image (FIG. 18), HAADF-STEM image and STEM-EDX map (FIG. 19). .

実施例8
ジエチレングリコール(DEG、還元剤) 10mlにHAuBr4(0.03 mmol)及びRuCl3(0.07 mmol)を溶解した(以下、「前駆体溶液」という)。
エチレングリコール(EG、還元剤) 100 mlにPVP(4 mmol)を加えて撹拌し、溶液を195℃に加熱した。この溶液の温度を195℃に維持しながら前駆体溶液を1.5ml/minの速度でポンプにより加えた。さらに10分間195℃を維持し、室温まで冷却した。Au0.3Ru0.7固溶体ナノ粒子を沈殿物として遠心分離により回収し、真空下に乾燥した。得られた沈殿物はfcc構造を有する固溶体ナノ粒子であることが粉末X線回折(図17a)、TEM像(図18)、HAADF-STEM像およびSTEM-EDXマップ(図20)により確認された。また、図17aに示されるfcc-AuRu3とhcp-AuRu3のXRDパターンのTopas(Bruker AXS社製)によるRietveld解析の結果を図17c、図17dに示す。
Example 8
HAuBr 4 (0.03 mmol) and RuCl 3 (0.07 mmol) were dissolved in 10 ml of diethylene glycol (DEG, reducing agent) (hereinafter, referred to as “precursor solution”).
PVP (4 mmol) was added to 100 ml of ethylene glycol (EG, a reducing agent), stirred, and the solution was heated to 195 ° C. The precursor solution was pumped in at a rate of 1.5 ml / min while maintaining the temperature of the solution at 195 ° C. The temperature was maintained at 195 ° C. for an additional 10 minutes and cooled to room temperature. The Au 0.3 Ru 0.7 solid solution nanoparticles were collected as a precipitate by centrifugation and dried under vacuum. The obtained precipitate was confirmed to be solid solution nanoparticles having an fcc structure by powder X-ray diffraction (FIG. 17 a), TEM image (FIG. 18), HAADF-STEM image and STEM-EDX map (FIG. 20). . 17c and 17d show the results of Rietveld analysis of the XRD patterns of fcc-AuRu 3 and hcp-AuRu 3 shown in FIG. 17a by Topas (manufactured by Bruker AXS).

試験例4
[電極の製造]
参考例1のfcc構造のPd0.4Ru0.6固溶体ナノ粒子又は実施例1のhcp構造のPd0.4Ru0.6固溶体ナノ粒子(53分間300℃処理)をカーボン粒子に担持したfcc又はhcpのPdRu固溶体回転リングディスク電極(PdRu/C:金属量20wt%)を製造した。回転リングディスク電極(RDE)の直径は5mmであった。また、電極上のPd0.4Ru0.6固溶体ナノ粒子の装填量は0.051mg/cmであった。
[HER(水素発生反応) 触媒活性]
電流測定装置:ポテンシオスタット(BAS社製 ALS760E)
測定方法:参考例1のfccのPd0.4Ru0.6固溶体ナノ粒子又は実施例1のhcpのPd0.4Ru0.6固溶体ナノ粒子(53分間300℃処理)をカーボン粒子に担持したfcc又はhcpのPdRu固溶体回転リングディスク電極(PdRu/C:金属量20wt%)をカソードとし、3電極式セル(対極:白金線、参照極:銀−塩化銀電極(Ag/AgCl)、電解液:0.1MのHClO水溶液、25℃、Ar-飽和、1600rpm)を用いて、−0.2Vから0V(vs.RHE)まで5mV/sにて電位Eを掃引したときの電流値Iを測定し、HER触媒活性を評価した。比較のために電極材料をPdRu固溶体ナノ粒子に代えてRuナノ粒子(Ru NPs)、Pdナノ粒子(Pd NPs)を用いて同様にHER触媒活性を測定した。結果を図21に示す。図21に示されるように、fccPdRuはPdに比べ活性が低いのに対し、hcpPdRuはPdよりも高い活性を示す。
Test example 4
[Production of electrodes]
Pd 0.4 Ru 0.6 solid solution nanoparticles or Pd 0.4 Ru 0.6 solid solution nanoparticles (53 min 300 ° C. treatment) were supported on carbon particles fcc or PdRu solid solution rotational ring hcp the hcp structure of the first embodiment of the fcc structure of Reference Example 1 A disk electrode (PdRu / C: metal amount 20 wt%) was manufactured. The diameter of the rotating ring disk electrode (RDE) was 5 mm. Further, the loading amount of the Pd 0.4 Ru 0.6 solid solution nanoparticles on the electrode was 0.051 mg / cm 2 .
[HER (hydrogen generation reaction) catalytic activity]
Current measuring device: potentiostat (ALS760E manufactured by BAS)
Measuring method: fcc or hcp PdRu solid solution rotation in which fcc Pd 0.4 Ru 0.6 solid solution nanoparticles of Reference Example 1 or hcp Pd 0.4 Ru 0.6 solid solution nanoparticles of Example 1 (treated at 300 ° C. for 53 minutes) are supported on carbon particles. Ring electrode (PdRu / C: metal content 20 wt%) as cathode, three-electrode cell (counter electrode: platinum wire, reference electrode: silver-silver chloride electrode (Ag / AgCl), electrolyte: 0.1 M HClO 4 Using an aqueous solution, 25 ° C., Ar-saturation, 1600 rpm), the current value I was measured when the potential E was swept from −0.2 V to 0 V (vs. RHE) at 5 mV / s, and the HER catalyst activity was measured. evaluated. For comparison, HER catalytic activity was measured in the same manner using Ru nanoparticles (Ru NPs) and Pd nanoparticles (Pd NPs) instead of PdRu solid solution nanoparticles as the electrode material. The results are shown in FIG. As shown in FIG. 21, fccPdRu has lower activity than Pd, whereas hcpPdRu shows higher activity than Pd.

試験例5
[電極の製造]
実施例7のhcp構造のAu0.3Ru0.7固溶体ナノ粒子又は実施例8のhcpのAu0.3Ru0.7固溶体ナノ粒子をカーボン粒子に担持したfcc又はhcpのAuRu固溶体回転リングディスク電極(AuRu/C:金属量20wt%)を製造した。電極上のAu0.3Ru0.7固溶体ナノ粒子の装填量は0.1mg/cmであった。
[OER(酸素発生反応)触媒活性]
電流測定装置:ポテンシオスタット(BAS社製 ALS760E)
測定方法:実施例7のhcp結晶構造のAu0.3Ru0.7固溶体ナノ粒子又は実施例8のfcc結晶構造のAu0.3Ru0.7固溶体ナノ粒子をカーボンに担持した回転リングディスク電極をアノードとし、3電極式セル(対極:白金線、参照極:銀−塩化銀電極(Ag/AgCl)、電解液:0.05MのHSO、25℃、Ar飽和)を用いて、1Vから2.0V(vs.RHE)まで5mV/sにて電位Eを掃引したときの電流値Iを測定した。比較のために電極材料をAu0.3Ru0.7固溶体ナノ粒子に代えて、Auナノ粒子(Au NPs)、Ruナノ粒子(Ru NPs)を用いて同様にOER触媒活性を測定した。結果を図22に示す。Ruは約1.5V以降、触媒の溶出に伴う活性の低下が観測されるが、fcc固溶体の場合は1.6V以降に徐々に活性の低下が見られ、測定回数に伴い活性が低下。一方、hcp固溶体では活性の低下は観測されず、5000回の測定でも活性を維持する。Au0.3Ru0.7固溶体ナノ粒子の結晶構造制御による触媒特性の向上が観測された。
Test example 5
[Production of electrodes]
Embodiment Au 0.3 Ru 0.7 solid solution nanoparticles or Au 0.3 Ru 0.7 solid solution nanoparticles of hcp of Example 8 were supported on carbon particles fcc or hcp AuRu solid solution rotating ring disk electrode of the hcp structure of Example 7 (AuRu / C: Metal 20 wt%). The loading of the Au 0.3 Ru 0.7 solid solution nanoparticles on the electrode was 0.1 mg / cm 2 .
[OER (Oxygen evolution reaction) catalytic activity]
Current measuring device: potentiostat (ALS760E manufactured by BAS)
Measuring method: A three-electrode system using a rotating ring disk electrode carrying Au 0.3 Ru 0.7 solid solution nanoparticles of hcp crystal structure of Example 7 or Au 0.3 Ru 0.7 solid solution nanoparticles of fcc crystal structure of Example 8 on carbon as an anode Using a cell (counter electrode: platinum wire, reference electrode: silver-silver chloride electrode (Ag / AgCl), electrolyte solution: 0.05 M H 2 SO 4 , 25 ° C., Ar saturation), from 1 V to 2.0 V (vs. .RHE), the current value I when sweeping the potential E at 5 mV / s was measured. For comparison, the OER catalytic activity was similarly measured using Au nanoparticles (Au NPs) and Ru nanoparticles (Ru NPs) in place of the Au 0.3 Ru 0.7 solid solution nanoparticles as the electrode material. The results are shown in FIG. For Ru, the activity decreases with the elution of the catalyst after about 1.5 V, but in the case of the fcc solid solution, the activity gradually decreases after 1.6 V, and the activity decreases with the number of measurements. On the other hand, no decrease in the activity was observed in the hcp solid solution, and the activity was maintained even after 5000 measurements. Improvement of catalytic properties by controlling the crystal structure of Au 0.3 Ru 0.7 solid solution nanoparticles was observed.

Claims (15)

式PdxRu1-x(0.1≦x≦0.8)で表わされる、 PdとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)であるPdRu固溶体ナノ粒子。PdRu solid solution nanoparticles represented by the formula Pd x Ru 1-x (0.1 ≦ x ≦ 0.8), in which Pd and Ru form a solid solution at the atomic level and have a main structure of a hexagonal close-packed structure (hcp). 0.4≦x≦0.6である、請求項1に記載のナノ粒子。The nanoparticles of claim 1, wherein 0.4 ≦ x ≦ 0.6. hcpの割合が80%以上である、請求項1又は2に記載のナノ粒子。The nanoparticles according to claim 1 or 2, wherein the proportion of hcp is 80% or more. hcpの割合が90%以上である、請求項3に記載のナノ粒子。4. The nanoparticles according to claim 3, wherein the proportion of hcp is 90% or more. 請求項1〜4のいずれか1項に記載のナノ粒子を担体に担持してなる触媒。A catalyst comprising the carrier according to any one of claims 1 to 4. 水添反応用触媒、水素酸化反応用触媒、酸素還元反応用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒又は水素燃料電池用触媒である、請求項5に記載の触媒。Catalyst for hydrogenation reaction, catalyst for hydrogen oxidation reaction, catalyst for oxygen reduction reaction, catalyst for oxygen evolution reaction (OER), catalyst for hydrogen evolution reaction (HER), catalyst for nitrogen oxide (NOx) reduction reaction, carbon monoxide The catalyst according to claim 5, which is a (CO) oxidation reaction catalyst, a dehydrogenation reaction catalyst, a VVOC or VOC oxidation reaction catalyst, an exhaust gas purification catalyst, a water electrolysis reaction catalyst, or a hydrogen fuel cell catalyst. 水電解反応用触媒である、請求項6に記載の触媒。The catalyst according to claim 6, which is a catalyst for a water electrolysis reaction. 面心立方格子構造(fcc)が主構造である式PdRu固溶体ナノ粒子を水素雰囲気で加熱してfcc結晶構造の一部または全部をhcp結晶構造に変換することを特徴とする、式Pd xRu1-x(0.1≦x≦0.8)で表わされる、Pd とRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)である固溶体ナノ粒子の製造方法。The formula Pd x Ru, wherein the PdRu solid solution nanoparticles having a face-centered cubic lattice structure (fcc) as a main structure are heated in a hydrogen atmosphere to convert a part or all of the fcc crystal structure to an hcp crystal structure. A method for producing solid solution nanoparticles represented by 1-x (0.1 ≦ x ≦ 0.8) in which Pd and Ru form a solid solution at an atomic level and have a main structure of a hexagonal close-packed structure (hcp). 液体還元剤を含む加熱溶液にPt化合物とRu化合物を含む溶液を添加する工程を含み、前記液体還元剤の加熱温度がPt化合物の還元温度〜前記還元温度+15℃であればhcpが主構造になり、前記液体還元剤の加熱温度がPt化合物の還元温度+15℃超であればfccが主構造になることを特徴とする、式PtyRu1-y(0.05≦y≦0.3)で表わされるPtRu固溶体ナノ粒子の結晶構造における六方最密構造(hcp)と面心立方格子(fcc)の割合を制御する方法。The method includes a step of adding a solution containing a Pt compound and a Ru compound to a heating solution containing a liquid reducing agent, and if the heating temperature of the liquid reducing agent is from the reduction temperature of the Pt compound to the reduction temperature + 15 ° C, hcp is the main structure. If the heating temperature of the liquid reducing agent is higher than the reduction temperature of the Pt compound + 15 ° C., fcc has a main structure, and is represented by the formula Pt y Ru 1-y (0.05 ≦ y ≦ 0.3). A method of controlling the ratio of hexagonal close-packed structure (hcp) and face-centered cubic lattice (fcc) in the crystal structure of PtRu solid solution nanoparticles. 式AuzRu1-z(0.05≦z≦0.4)で表わされる、 AuとRuが原子レベルで固溶し、かつ、主構造が六方最密構造(hcp)又は面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子。Au and Ru represented by the formula Au z Ru 1-z (0.05 ≦ z ≦ 0.4), where Au and Ru form a solid solution at the atomic level, and the main structure is a hexagonal close-packed structure (hcp) or a face-centered cubic lattice structure (fcc) AuRu solid solution nanoparticles. 主構造が六方最密構造(hcp)である、請求項10に記載のAuRu固溶体ナノ粒子。The AuRu solid solution nanoparticles according to claim 10, wherein the main structure is a hexagonal close-packed structure (hcp). 主構造が面心立方格子構造(fcc)である、請求項10に記載のAuRu固溶体ナノ粒子。The AuRu solid solution nanoparticles according to claim 10, wherein the main structure is a face-centered cubic lattice structure (fcc). 液体還元剤を含む加熱溶液にAu化合物とRu化合物を含む溶液を添加する工程を含む、主構造が面心立方格子構造(fcc)であるAuRu固溶体ナノ粒子の製造方法。A method for producing AuRu solid solution nanoparticles whose main structure is a face-centered cubic lattice structure (fcc), comprising a step of adding a solution containing an Au compound and a Ru compound to a heating solution containing a liquid reducing agent. CTAB(Cetyl trimethyl ammonium bromide)と液体還元剤を含む加熱溶液にAu化合物とRu化合物を含む溶液を添加する工程を含む、主構造が六方最密構造(hcp)であるAuRu固溶体ナノ粒子の製造方法。A method for producing AuRu solid solution nanoparticles whose main structure is a hexagonal close-packed structure (hcp), including a step of adding a solution containing an Au compound and a Ru compound to a heating solution containing CTAB (Cetyl trimethyl ammonium bromide) and a liquid reducing agent . 請求項11又は12に記載のナノ粒子を担体に担持してなり、水添反応用触媒、水素酸化反応用触媒、酸素還元反応用触媒、酸素発生反応(OER)用触媒、水素発生反応(HER)用触媒、窒素酸化物(NOx)還元反応用触媒、一酸化炭素(CO)酸化反応用触媒、脱水素反応用触媒、VVOC又はVOC酸化反応用触媒、排ガス浄化用触媒、水電解反応用触媒又は水素燃料電池用触媒である、触媒。A carrier comprising the nanoparticles according to claim 11 or 12, comprising a hydrogenation reaction catalyst, a hydrogen oxidation reaction catalyst, an oxygen reduction reaction catalyst, an oxygen generation reaction (OER) catalyst, and a hydrogen generation reaction (HER ), Nitrogen oxide (NOx) reduction catalyst, carbon monoxide (CO) oxidation reaction catalyst, dehydrogenation reaction catalyst, VVOC or VOC oxidation reaction catalyst, exhaust gas purification catalyst, water electrolysis reaction catalyst Or a catalyst which is a catalyst for a hydrogen fuel cell.
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