Isolated Pd atom anchoring endows cobalt diselenides with regulated water-reduction kinetics for alkaline hydrogen evolution

Abstract The adsorption and dissociation of water as well as hydrogen adsorption represent three crucial processes in alkaline hydrogen evolution reaction (HER) catalysis. It is still a big challenge to simultaneously regulate these three processes to realize high-performance HER of catalysts in alkaline electrolytes. Herein, we demonstrate a facile approach to synthesize isolated Pd atom-anchored CoSe2 (Pd1-CoSe2) nanobelts with synergistically regulated reaction processes for alkaline HER. Mechanistic studies reveal that the anchoring of isolated Pd atoms in Pd1-CoSe2 can powerfully promote the adsorption and dissociation of water owing to the upward shifted d-band center of surface sites. Meanwhile, the strong interactions between Pd atoms and CoSe2 enable the well-tailored adsorption of hydrogen on Pd1-CoSe2. Accordingly, relative to pure CoSe2, Pd1-CoSe2 shows a remarkably increased current and a much-lowered Tafel slope towards alkaline HER. This strategy provides an atomic-level-regulating strategy to design active catalysts with synergistically regulated reaction kinetics for heterogeneous electrocatalysis.