Porous cobalt sulfide nanosheets arrays with low valence copper incorporated for boosting alkaline hydrogen evolution via lattice engineering

Design and development of high-performance non-precious electrocatalysts for clean and renewable energy production remain huge challenging. In this work, porous cobalt sulfide nanosheets arrays with low valence copper incorporated supported on nickel foam (Cu-CoSx/NF) is constructed by a hydrothermal strategy assisted with sulfur vapor etching. which exhibits admirable alkaline hydrogen evolution activity with the low overpotentials of 75 and 203 mV at 10 and 300 mA cm−2, respectively, leading to high performance in alkaline HER than those of reported cobalt sulfide-based catalysts and even outperforms Pt/C at high current density. The introduction of low valence copper induces the lattice contraction of CoSx, resulting in the enrichment of electron cloud density nearly at Co active sites, and thereby optimizing the kinetics of hydrogen evolution and the adsorption behaviors of reactants, therefore, elevating the electrocatalytic activities. Furthermore, the synthesized Cu-CoSx/NF catalyst acted as the cathode in alkaline Zn-H2O cell demonstrating the potential applications of the newly developed hydrogen evolution catalyst. This work would shed light on more in-depth insight into doping of metal species-induced lattice contraction in the design of outstanding electrocatalysts.