title: Universal dependence of hydrogen oxidation and evolution reaction activity of platinum-group metals on pH and hydrogen binding energy.
abstract: Understanding how pH affects the activity of hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is key to developing active, stable, and affordable HOR/HER catalysts for hydroxide exchange membrane fuel cells and electrolyzers. A common linear correlation between hydrogen binding energy (HBE) and pH is observed for four supported platinum-group metal catalysts (Pt/C, Ir/C, Pd/C, and Rh/C) over a broad pH range (0 to 13), suggesting that the pH dependence of HBE is metal-independent. A universal correlation between exchange current density and HBE is also observed on the four metals, indicating that they may share the same elementary steps and rate-determining steps and that the HBE is the dominant descriptor for HOR/HER activities. The onset potential of CO stripping on the four metals decreases with pH, indicating a stronger OH adsorption, which provides evidence against the promoting effect of adsorbed OH on HOR/HER.
authors.affiliation: Department of Chemical and Biomolecular Engineering and Center for Catalytic Science and Technology, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Sheng
authors.affiliation: Department of Chemical and Biomolecular Engineering and Center for Catalytic Science and Technology, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
authors.forename: Zhongbin
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: Department of Chemical and Biomolecular Engineering and Center for Catalytic Science and Technology, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
authors.forename: Bingjun
authors.initials: B
authors.lastname: Xu
authors.affiliation: Department of Chemical and Biomolecular Engineering and Center for Catalytic Science and Technology, University of Delaware, 150 Academy Street, Newark, DE 19716, USA.
authors.forename: Yushan
authors.initials: Y
authors.lastname: Yan
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry; D002384:Catalysis; D004563:Electrochemistry; D004573:Electrolytes; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000737:chemistry*; D010084:Oxidation-Reduction; D010984:Platinum / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D008670:Metals; D010984:Platinum; D002248:Carbon Monoxide; D006859:Hydrogen
keywords: Hydrogen oxidation and evolution reaction; Pt-group metals; electrocatalysis; hydrogen binding energy