3D Ni-Co sulfoxide nanosheet arrays electrodeposited on Ni foam: A bifunctional electrocatalyst towards efficient and stable water splitting

摘要

Developing highly active and stable electrocatalysts from earth-abundant elements are imperative for the large-scalable production of hydrogen. Herein, the three dimensional amorphous NiCoSxOynanosheets arrays directly grow on Ni foam (NiCoSxOyNSs/NF) through a facile one-step electrodeposition is firstly reported. The special in-situ grown 3D nanosheets arrays, largely exposed active sites and enhanced electrical conductivity enable the resultant NiCoS0.14O3.25NSs/NF to possess remarkable electrocatalytic performance and stability towards water splitting in 1?M KOH. Specifically, the introduction of S ligand into the hydroxides through a straightforward and convenient electrodeposition method boost the robust composition and comprehensive activity of the NiCoSxOyNSs. Such binder-free, easily prepared NiCoS0.14O3.25NSs/NF electrode requires the overpotential of 250?mV and 170?mV?at 10?mA?cm?2for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. When functionalizing as two identical cathode and anode in an alkaline electrolyzer, NiCoS0.14O3.25NSs/NF displays the efficient and robust property on both OER and HER. Remarkably, serving as bifunctional electrode in alkaline electrolyzer, it only needs 1.64?V to reach the current density of 20?mA?cm?2. This study provides a valuable guideline to synthesize non-noble and efficient bifunctional electrocatalysts using a time-saving but facile electrochemical method.