Small‐Sized and Contacting Pt–WC Nanostructures on Graphene as Highly Efficient Anode Catalysts for Direct Methanol Fuel Cells |
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Authors: | Dr. Ruihong Wang Dr. Ying Xie Dr. Keying Shi Dr. Jianqiang Wang Dr. Chungui Tian Prof. Peikang Shen Prof. Honggang Fu |
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Affiliation: | 1. Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080 (P. R. China), Fax: (+86)?451‐8666‐1259;2. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhang Heng Road, Pudong District, Shanghai 201204 (P. R. China);3. Department of Physics and Engineering, Sun Yat‐sen University, Guangzhou, 510275 (P. R. China), Fax: (+86)?20‐8411‐3369 |
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Abstract: | The synergistic effect between Pt and WC is beneficial for methanol electro‐oxidation, and makes Pt–WC catalyst a promising anode candidate for the direct methanol fuel cell. This paper reports on the design and synthesis of small‐sized and contacting Pt–WC nanostructures on graphene that bring the synergistic effect into full play. Firstly, DFT calculations show the existence of a strong covalent interaction between WC and graphene, which suggests great potential for anchoring WC on graphene with formation of small‐sized, well‐dispersed WC particles. The calculations also reveal that, when Pt attaches to the pre‐existing WC/graphene hybrid, Pt particles preferentially grow on WC rather than graphene. Our experiments confirmed that highly disperse WC nanoparticles (ca. 5 nm) can indeed be anchored on graphene. Also, Pt particles 2–3 nm in size are well dispersed on WC/graphene hybrid and preferentially grow on WC grains, forming contacting Pt–WC nanostructures. These results are consistent with the theoretical findings. X‐ray absorption fine structure spectroscopy further confirms the intimate contact between Pt and WC, and demonstrates that the presence of WC can facilitate the crystallinity of Pt particles. This new Pt–WC/graphene catalyst exhibits a high catalytic efficiency toward methanol oxidation, with a mass activity 1.98 and 4.52 times those of commercial PtRu/C and Pt/C catalysts, respectively. |
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Keywords: | density functional calculations electrochemistry graphene nanostructures platinum |
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