Dopant triggered atomic configuration activates water splitting to hydrogen.

Finding highly efficient hydrogen evolution reaction (HER) catalysts is pertinent to the ultimate goal of transformation into a net-zero carbon emission society. The design principles for such HER catalysts lie in the well-known structure-property relationship, which guides the synthesis procedure that creates catalyst with target properties such as catalytic activity. Here we report a general strategy to synthesize 10 kinds of single-atom-doped CoSe 2 -DETA (DETA = diethylenetriamine) nanobelts. By systematically analyzing these products, we demonstrate a volcano-shape correlation between HER activity and Co atomic configuration (ratio of Co-N bonds to Co-Se bonds). Specifically, Pb-CoSe 2 -DETA catalyst reaches current density of 10 mA cm -2 at 74 mV in acidic electrolyte (0.5 M H 2 SO 4 , pH ~0.35). This striking catalytic performance can be attributed to its optimized Co atomic configuration induced by single-atom doping.