Synthesis of an active and stable Pt_shell-Pd_core/C catalyst for the electro-oxidation of methanol

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• 作者：Insoo Choi ; Sang Hyun Ahn ; Myeong Ho Kim ; Oh Joong Kwon ; Jae Jeong Kim
• 关键词：Platinumshell&ndash ; Palladiumcore ; Catalyst ; Methanol ; Oxidation ; Carbon monoxide-poisoning ; Direct methanol fuel cell
• 刊名：International Journal of Hydrogen Energy
• 出版年：6 March, 2014
• 年：2014
• 卷：39
• 期：8
• 页码：3681-3689
• 全文大小：1983 K

文摘

A Pt_shell-Pd_core/C catalyst is prepared via electroless deposition and galvanic displacement. The catalyst is active toward the electro-oxidation of methanol and is more stable against CO_ad-poisoning than a commercial Pt/C catalyst. The stable activity of Pt_shell-Pd_core/C is ascribed to the tuned electronic property of the Pt over-layer in the Pt_shell-Pd_core/C, which leads to weak binding with CO_ad and increases the kinetics of OH_ad formation. The weakened binding property of the surface Pt with CO_ad and the facile oxidation of CO_ad by OH_ad were confirmed by a spectroscopic analysis and in a CO_ad-stripping experiment, respectively. The electro-oxidation of CO_ad by OH_ad is the rate-determining step of methanol oxidation. Therefore, the accelerated formation of OH_ad contributes to the overall oxidation reaction, preventing CO_ad-poisoning. In addition, Pt_shell-Pd_core/C maintains its activity longer than Pt/C does during a prolonged cycle experiment.