In Situ Observation of How Pt Catalyst Evolves in Pulsed Electrolysis

Pulsed electrochemical methods have emerged as a simple and effective approach for increasing catalyst durability and improving product selectivity. However, mechanistic understanding is primarily derived from traditional experimental techniques or theoretical calculations, which only provide ex situ information and prevent accurate analysis of electrochemical processes. In this study, we developed a novel potential modulated difference X-ray absorption fine structure (PM-diffXAFS) spectroscopy technique for the in situ observation of the dynamic evolution of Pt catalysts in pulsed electrolysis at the atomic level. The near-surface layers of the Pt catalyst underwent periodic oxidation and reduction within a few seconds, while the oxygen species that entered the bulk of the Pt catalyst were maintained, while the oxidation state was much lower at high potential under pulsed conditions than that under steady conditions, which was helpful for preventing the overoxidation of Pt catalysts. Besides, the tailored oxidation state could be achieved by adjusting the pulsed potential and duration. The present study provides a novel approach to understanding the pulse electrolysis process, and the strategy developed in this work offers guidance for optimizing the stability and selectivity of catalysts.