Diffusion limitation of hydrogen evolution reaction (HER) demystified

UntitledJie’s recent work demonstrates that HER could also be diffusion limited when the electrode kinetics is fast, despite widely held belief to the contrary. The HER diffusion limitation originates from the insufficient mass transport of produced H2 from the electrode surface to the bulk electrolyte and the highly reversible nature of HOR/HER.  A general data analysis protocol based on the reversible Koutecky-Levich equation is developed to obtain accurate kinetic information of HOR/HER.