Boosting the electrocatalytic performance of Co2P/Ni3S2 heterostructure for efficient water splitting

The development of a catalyst exhibiting outstanding catalytic activity and robust stability for both the oxygen evolution reaction and hydrogen evolution reaction in alkaline media represents a substantial challenge. In this work, a NF/Ni@NiCoSP heterostructure bifunctional catalyst was developed via a sequent process of electrodeposition-hydrothermal-low temperature thermal pyrolysis sulphuration/phosphorization. The physical characterizations reveal that the as-prepared sample of NF/Ni@NiCoSP exhibits a porous nano-needles array structure and consists of both Ni3S2 and Co2P phases with considerable boundaries. As a consequence, the NF/ Ni@NiCoSP presents an ultralow overpotential of 47 mV and 260 mV at 10 mA cm(-2) for hydrogen evolution reaction and oxygen evolution reaction, respectively. When assembled to a two-electrode system, it only requires 1.53 V to reach 10 mA cm(-2), which surpasses the commercial RuO2 & Vert;Pt/C (1.61 V). The methanol oxidation reaction probing experiment suggests the easy desorption of *OH from active sites due to the decreased binding strength between *OH and the catalyst, thus optimizing the kinetics condition. Moreover, the in-situ Raman spectra reveal that NiOOH and CoOOH serve as active sites for OER while the metal sites for HER. Therefore, this work introduces a feasible strategy to design cost-effective and robust catalysts with excellent catalytic properties, thereby paving the way for water splitting.