Enhance the performance of OER electrocatalyst via synergistic oxygen vacancies and NiFe2O4-phosphorene heterostructure

Abstract

The exfoliated black phosphorus nanosheets (EBP, phosphorene) is considered as a highly anticipated electrocatalyst for oxygen evolution reaction (OER) because of its unique electron structure. However, the poor stability and conductivity of EBP limit its application potential. In this paper, a heterostructure of EBP and nickel ferrite with oxygen vacancies (NFO-V-EBP) is designed by using a simple ultrasound and electronic regulation of EBP. NFO-V forms P-Ni bonds and P-O-M (M=Ni/Fe) bonds by interacting with the active lone pair electrons on the surface of EBP, which passivates EBP to improve its stability and provide more active sites. In situ Raman testing is used to assist in demonstrating the cooperative effect of EBP and oxygen vacancy, which reduced the potential barrier of OER reaction. NFO-V-EBP heterostructure exhibits excellent electrocatalytic performance for alkaline OER, showing overpotential of 243 mV at current density of 10 mA cm-2 and Tafel slope of 39 mV dec-1. It also has excellent long-term stability, at a density of 10 mA cm-2 with no significant increase in overpotential observed after nearly 100 hours under the chronoamperometric method.