Coral-like S-doped CoSe2 with enriched 1T-phase as efficient electrocatalyst for hydrogen evolution reaction

Developing high-efficiency electrocatalysts for water splitting is considered as a promising strategy to generate hydrogen addressing the current energy issues. CoSe2 is a promising electrocatalyst for water splitting due to its intrinsic metallicity, but its application is limited by the chemically inert basal plane and thus lack of active sites. Herein, we investigate the effect of growth condition on hydrogen evolution by changing the doped sulfur amount. The optimized coral-like CoS0.1Se1.9 with enriched 1T-phase exhibits robust hydrogen evolution reaction(HER) activity, which is evidenced from mere −157 mV (vs. RHE) is needed to afford a current density of 10 mA cm−2, a small Tafel slope of 28.2 mV dec−1 and remarkable long-term stability. This enhancement may be attributed to the increase of active sites and improved conductivity, resulting from the tuned morphology and electronic structure of CoS0.1Se1.9. This work paves a novel route in the rational design and facile synthesis of superior nonprecious electrocatalysts with striking HER performance for practical utilization.