Determining the hydronium pKα at platinum surfaces and the effect on pH-dependent hydrogen evolution reaction kinetics
Guangyan Zhong, Tao Cheng, Aamir Hassan Shah, Chengzhang Wan, Zhihong Huang, Sibo Wang, Tianle Leng, Yu Huang, William A Goddard III, Xiangfeng Duan
PNAS 119, e2208187119 (2022)
Electrocatalytic hydrogen evolution reaction (HER) exhibits distinct pH-dependent kinetics that have been elusive to understand. Understanding the electrochemical interfaces is essential for developing more efficient electrochemical processes. In this research, we combine experiment and theory to establish a molecular-level understanding of the electrochemical interfaces. An exclusively surface-specific electrical transport spectroscopy approach probes the Pt-surface water protonation status and experimentally determines the surface hydronium pKα = 4.3. These insights offer a molecular-level interpretation of pH-dependent HER kinetics and may help design improved electrocatalysts for renewable energy conversion.