Designing a smart heterojunction coupling of cobalt-iron layered double hydroxide on nickel selenide nanosheets for highly efficient overall water splitting kinetics

TLDR: In this article , an interface engineering approach was developed to fabricate NiSe coupled with CoFe LDH in which the hierarchical assembly of heteronanostructured nanosheets exhibited excellent electrocatalytic performance for overall water splitting.

Abstract: To design heterojunction electrocatalysts for water splitting in industrial plants, replacing RuO 2 , IrO 2 , and Pt/C remains challenging. We prepared heterostructures of nickel selenide (NiSe) and cobalt-iron layer double hydroxide (CoFe LDH), CoFe LDH@NiSe, using hydrothermal and electrodeposition processes. The interfacial coupling enhanced the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). The CoFe LDH@NiSe required an overpotential of 127 mV and 38 mV for a current density of 10 mA cm −2 with a Tafel slope of 37 mV dec −1 and 33 mV dec −1 for OER and HER in alkaline solutions. Density functional theory calculations showed the enhancement of OER performance. The catalytic activity of CoFe LDH@NiSe increased the electronic conductivity, enhancing the water splitting with 10 mA cm −2 at 1.51 V. The robustness was demonstrated by the long-term stability for 120 h. This study provides a strategy for developing heteronanostructure electrocatalysts for water splitting in fields such as metal-air batteries and energy storage. An interface engineering approach was developed to fabricate NiSe coupled with CoFe LDH in which the hierarchical assembly of heteronanostructured nanosheets exhibited excellent electrocatalytic performance for overall water splitting kinetics. • CoFe-LDH@NiSe nanosheets were prepared by hydrothermal/electrodeposition method. • The mass activity of CoFe-LDH@NiSe surpasses the state-of-the-art electrocatalysts. • DFT proves abundant vacant active sites enhancing the performance of OER. • The designed heteronanostructure exhibits an excellent catalytic performance.