Construction of Mo-doped NiFe-LDH/NiCoP heterostructure electrocatalyst for enhancing urea-assisted overall water splitting performance

Abstract

In this work, we employed cation doping and interfacial engineering strategies to develop a multifunctional electrocatalyst composed of NiCoP and Mo-NiFe-LDH on a nickel foam substrate (designated as Mo-NiFe-LDH/NiCoP/NF) to enhance overall water splitting performance. The synthesized Mo-NiFe-LDH/NiCoP/NF electrocatalyst demonstrates superior activity and stability for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), evidenced by low overpotentials of 194 mV for OER and 104 mV for HER at a current density of 10 mA cm⁻², as well as a low Tafel slope. In addition, the urea oxidation reaction (UOR) performance of Mo-NiFe-LDH/NiCoP/NF reveals fast reaction kinetics and a significantly lower driving potential compared to that of OER. This exceptional electrocatalytic performance can be attributed to modulation of the electronic structure and the synergistic effects between Mo-NiFe-LDH and NiCoP, which enhance the electrochemical active area, increase the number of active sites, and promote strong electron interactions. Furthermore, when utilized for electrochemical overall water splitting and urea-assisted water electrolysis, the Mo-NiFe-LDH/NiCoP/NF achieves a current density of 10 mA cm⁻² at only 1.53 V and 1.34 V, respectively. These values surpass those of Pt–C‖RuO₂ and numerous non-precious metal electrocatalysts, while also maintaining stable performance over a prolonged electrolytic operation period of 50 h. This work presents a promising pathway for the design of efficient catalysts for urea-assisted water electrolysis.