Ruthenium-Alloy Electrocatalysts with Tunable Hydrogen Oxidation Kinetics in Alkaline Electrolyte

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• 作者：Samuel St. John ; Robert W. Atkinson ; III ; Raymond R. Unocic ; Thomas A. Zawodzinski ; Jr. ; Alexander B. Papandrew
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：13481-13487
• 全文大小：421K
• ISSN：1932-7455

文摘

High-surface-area ruthenium-based Ru_xM_y (M = Pt or Pd) alloy catalysts supported on carbon black were synthesized to investigate the hydrogen oxidation reaction (HOR) in alkaline electrolytes. The exchange current density for hydrogen oxidation on a Pt-rich Ru_0.20Pt_0.80 catalyst is 1.42 mA/cm², nearly 3 times that of Pt (0.490 mA/cm²). Furthermore, Ru_xPt_y alloy surfaces in 0.1 M KOH yield a Tafel slope of 鈭?0 mV/dec, in contrast with the 鈭?25 mV/dec Tafel slope observed for supported Pt, signifying that hydrogen dissociative adsorption is rate-limiting rather than charge-transfer processes. Ru alloying with Pd does not result in modified kinetics. We attribute these disparate results to the interplay of bifunctional and ligand effects. The dependence of the rate-determining step on the choice of alloy element allows for tuning catalyst activity and suggests not only that a low-cost, alkaline anode catalyst is possible but also that it is tantalizingly close to reality.