Electrochemical Imaging of Hydrogen Evolution Reaction Sites at Transition Metal Dichalcogenide Nanosheets

Understanding spatial heterogeneity in catalytic activity is essential for designing efficient hydrogen evolution reaction (HER) catalysts. In this study, scanning electrochemical cell microscopy (SECCM) was employed to directly image local HER activity on transition metal dichalcogenide (TMD) nanosheets. By resolving nanoscale electrochemical responses beyond conventional electrochemical measurements, SECCM revealed heterogeneous activity distributions associated with edges, morphology, and strain. Local analyses of nanoribbons, dendritic structures, and strain-engineered layers clarified how geometric and electronic modifications influence catalytic performance. These findings establish direct structure–activity correlations at the nanoscale and demonstrate the capability of SECCM as a powerful platform for guiding the design of next-generation non-precious HER electrocatalysts.