Interfacial Ni-N bond bridged Z-type g-C3N4/LaNi0.8Fe0.2O3 heterojunction for boosting photo-assisted oxygen evolution

Abstract

Perovskite oxides possess a flexible electronic structure suitable for electrocatalysis, yet their application in photo-assisted oxygen evolution reaction (OER) is often hindered by high photogenerated carrier recombination and limited intrinsic activity. To address these limitations, this study presents the first attempt to construct a Z-type g-C₃N₄/LaNi_0.8Fe_0.2O₃ (g-C₃N₄/LNFO) heterojunction composite for efficient photo-assisted OER performance. The strong electronic coupling via interfacial Ni-N bonds reduces charge transfer resistance, while the Z-type band alignment significantly enhances the separation efficiency of electron-hole pairs. Electrochemical evaluations demonstrate that under visible light illumination, the g-C₃N₄/LNFO catalyst requires an overpotential of only 335 mV to reach a current density of 10 mA cm⁻², representing a significant reduction of 55 mV compared to dark conditions. Furthermore, the catalyst exhibits a 70 mV improvement in overall water splitting performance and demonstrates excellent stability and rechargeability when assembled into a photo-assisted zinc-air battery. This study provides a pioneering strategy for designing energy-level matched heterojunctions to maximize the photo-assisted electrocatalytic potential of perovskite materials.