Insights on the Corrosion and Degradation of MXenes as Electrocatalysts for Hydrogen Evolution Reaction

Abstract MXenes, known as the graphene‐like two‐dimensional transition metal carbides, carbonitrides, or nitrides, have been considered as promising electrocatalysts to replace benchmark Pt for hydrogen evolution reaction (HER). Despite the success in fabricating MXenes, their application in catalysis still faces great challenges. One critical drawback is the rapid corrosion and structural evolution of MXenes during storage and HER. In this work, the corrosion and structural evolution of various MXenes in air, aqueous colloidal solutions, and under HER conditions are reviewed. The degradation/structural mechanism of MXenes and effects of structural evolution on the HER activity are in dispute. Preliminary protocols are proposed for future MXene storage and design for HER application. This review provides valuable information to better prevent corrosion of MXenes before and after servicing as HER catalysts, and to interpret the obtained HER performance for MXenes in the view of corrosion/structural evolution.