Ce-doped multi-phase NiMo-based phosphorus/sulfide heterostructure for efficient photo-enhanced overall water splitting at high current densities

Abstract

NiMo-based electrocatalysts are widely regarded as promising electrocatalysts for overall water splitting (OWS). However, to solve the problem of slow reaction kinetics and serious deactivation at high current density, the reasonable design of NiMo-based electrocatalysts is still a great challenge. In this work, NiMo-based phosphorus/sulfide heterostructure electrocatalysts with different Ce doping ratios (5%/10%/15%Ce-NiMo-PS@NF) have been designed using the combination of cation doping and heterostructure engineering. The doping of Ce not only changes the electronic environment of the heterostructure, accelerates the electron transport at the heterostructure interface, but also enhances the light absorption capacity of the heterostructure. The experimental results show that 10%Ce-NiMo-PS@NF has the best photo-enhanced electrocatalytic activity (hydrogen evolution reaction (HER): η1000 = 250 mV, oxygen evolution reaction (OER): η1000 = 242 mV, and OWS: E1000 = 1.864 V). In addition, its solar-to-hydrogen (STH) efficiency in a photoelectric coupled water splitting system is as high as 18.68%. This study not only provides a new method for the synthesis of new heterostructure electrocatalysts, but also provides a reference for the rational use of light energy to enhance electrocatalytic activity.