Constructing an n–n junction between CoFe-LDH and NiCoP as bifunctional electrocatalysts for efficient overall water splitting

Abstract

Utilizing transition metal elements (Ni, Fe, Co) to design heterojunction catalysts is an effective approach for enhancing the efficiency of electrocatalytic water splitting. In this study, an n–n type junction was constructed uniformly in a CoFe-LDH@NiCoP/NF electrode through electrodeposition. This not only enhanced the conductivity and kinetic performance but also improved the electrocatalytic stability of the catalysts. The presence of an n–n type junction facilitates electron rearrangement at the heterogeneous interface, resulting in the transfer of electrons from CoFe-LDH to NiCoP. As a result, the activity of overall water splitting with CoFe-LDH@NiCoP/NF as both the cathode and anode only required 1.735 V to reach 200 mA cm⁻²; the voltage dropped by only 13 mV after 3000 CV cycles and the current density decreased by a mere 18% in 138 h at 270 mA cm⁻². Therefore, the utilization of an n–n junction would provide more possibilities to regulate the electronic structure of electrocatalysts, especially in alkaline solutions.