Strong coupling effect induced surface reconstruction of CeF3–Ni3N to form CeF3–NiOOH for the oxygen evolution reaction

Abstract

The electrocatalytically active interface in a heterostructure is extremely crucial to obtain optimum adsorption energy of intermediates (O*, OH*, and HOO*) and faster electron transfer. Due to the slow kinetics of the electrocatalytic oxygen evolution reaction, the fabrication of such heterojunctions is indeed challenging. Herein, we have demonstrated that the CeF₃–NiOOH interface, formed through the anodic oxidation of strongly coupled CeF₃–Ni₃N for the oxygen evolution reaction (OER), displays significantly superior activity compared to NiOOH. X-ray photoelectron spectroscopy revealed the reallocation of charge from Ni₃N to CeF₃ through the interface. This charge transfer enhances the valence state of Ni present in Ni₃N making it more favourable for intermediate adsorption, which further helps in the rapid surface reconstruction to form highly active CeF₃–NiOOH. This phenomenon is governed by the high polarization of CeF₃ which drives electrons from Ni₃N, due to the existence of highly electron-withdrawing F atoms in CeF₃. An overpotential of 259 mV @ 10 mA cm⁻² and 380 mV @ 100 mA cm⁻² (current densities) respectively were observed. The chronoamperometry measurements of the catalyst show a stable plot for more than 100 h even at a high current density of 100 mA cm⁻². The exploration of surface reconstruction in strongly coupled heterointerfaces will offer new avenues for the creation of highly active catalysts for the oxygen evolution reaction.