Facile Preparation Process of NiCoP–NiCoSe2 Nano-Bilayer Films for Oxygen Evolution Reaction with High Efficiency and Long Duration

In order to explore a new electrocatalyst (or its precursor) for oxygen evolution reaction (OER), much attention has recently been given to the alternative engineering strategy for fabricating a novel nanofilm electrode with high efficiency and long duration. We herein use a two-step electrodeposition method to prepare a series of nanofilm electrodes containing Ni, Co, P, and Se on carbon cloth. After a suitable electrochemical activation process through cyclic voltammetry, the resultant binder-free NiCoP–NiCoSe2 nano-bilayer films are transformed from compact layer(s) to porous nanoparticle ones composed by NiCo hydroxides and a small amount of NiCo oxyhydroxides and thus exhibit a striking electrocatalytic activity (lower to 243 mV overpotential for 10 mA cm–2) and excellent stability (80 h) for OER. The rougher surface, well-suited electronic structure originated from the Ni/Co codoping and the rational integration of NiCoP and NiCoSe2 are important factors for the excellent OER performance of the NiCoP–NiCoSe2 film after the electrochemical activation process. In addition, the results on overall water splitting reveal that the NiCoP–NiCoSe2 film is also promising in the practical application of energy conversion and storage.