Bifunctional keel flower-like Ni-Co-V multicomponent oxide catalyst with enhanced electron transport for accelerating overall water splitting

Abstract

Heteroatom doping is considered a typical method for improving the electrochemical properties of composites. In this work, the multi-component oxide catalyst (Ni(VO3)2 and Co2V2O7 on Ni foam, referred to as NiCoVOx@NF) is formed by hydrothermal doping of V element into NiCo-based precursors followed by co-oxidation. In the catalyst NiCoVOx@NF, all three components of Ni, Co and V are particularly tightly coordinated, exhibiting an integrated structure of keel flower-like arrays. The catalyst NiCoVOx@NF’s contact surface with water is increased thanks to this unusual structure, exposing a high number of active sites. Furthermore, NiCoVOx@NF owns efficient electronic pathways, which greatly enhances the electron transport ability. To generate a current density of 10 mA cm−2 for hydrogen evolution reaction, just a 107 mV overpotential is required. The electrode exhibits a low overpotential of 217 mV to deliver 50 mA cm−2 for oxygen evolution reaction. In addition, the total water splitting performance of NiCoVOx@NF is also excellent, which could be achieved by only one 1.5 V AA battery. This study provides a feasible heteroatom doping route to design bifunctional catalysts with improved performances.