Mechanistic Insights into LSPR-Activated Bubble Detachment in the Hydrogen Evolution Reaction

The role of the localized surface plasmon resonance (LSPR) effect in promoting the efficiency of hydrogen production by enhancing the catalytic performance has been much studied, but it is a complex physical phenomenon involving electromagnetic and temperature fields, and little research has been conducted on the aspect of its effect on mass transfer. In this study, we investigate the kinetics of individual hydrogen bubble formation during the hydrogen evolution reaction (HER) under LSPR excitation on a microelectrode. Our results reveal a dramatic reduction in the bubble growth-to-detachment time, from 60 s to 0.9 s, accompanied by a two-orders-of-magnitude increase in the hydrogen generation rate. LSPR induced by Au nanoparticles (AuNPs) generates a thermal Marangoni flow at bubble interface, producing a detachment force of 59.10 μN, thereby improving mass transport and reaction efficiency. Increasing light intensity further optimizes mass transfer by shifting the reaction-control regime. These results highlight the multifunctional role of LSPR in enhancing both catalytic and mass-transfer processes in electrochemical hydrogen production, which has implications for LSPR-based photoelectrochemical (PEC) catalysis, electrochemical water splitting, and even CO 2 reduction.