Hydrothermal combined with electrodeposition construction of a stable Co9S8/Ni3S2@NiFe-LDH heterostructure electrocatalyst for overall water splitting

Electrochemical water splitting provides a prominent route towards clean energy conversion and storage, while unsuitable catalysts restrict its application. Core-shell hierarchical heterostructure materials with strong synergistic effects based on non-noble metal elements have been developed to compensate for inadequacy. In this work, a core-shell hierarchical heterostructure Co9S8/Ni3S2@NiFe-LDH electrocatalyst was prepared via hydrothermal and electrodeposition methods. The resultant Co9S8/Ni3S2@NiFe-120 electrocatalyst consists of Co9S8 substrates as the core and NiFe-LDHs as the shell, and exhibits excellent overall water splitting electrocatalytic activity with a low overpotential of 229 mV for the oxygen evolution reaction (OER), and 151 mV for the hydrogen evolution reaction (HER) and a full cell voltage of 1.62 V at 10 mA cm(-2) current density. The core-shell heterostructure constructed by electrodeposition endows the catalyst with outstanding stability and low degradation in long-term catalytic processes as shown by continuous chronopotentiometry tests at current densities of 50, 100 and 200 mA cm(-2) for 72 h. The as-prepared core-shell hierarchically heterostructural Co9S8/Ni3S2@NiFe-120 with high-efficiency and good-durability is a promising bifunctional electrocatalyst towards practical applications in overall water splitting.

Automated summary

An efficient electrocatalyst with core-shell hierarchical heterostructure has been developed, showing outstanding water splitting performance and promising practical applications.