Boosting interfacial bonding between FeOOH catalysts and Fe2O3 photoanodes toward efficient water oxidation

Abstract

Herein, we demonstrated a facile and feasible strategy for forming strong interfacial bonding between FeOOH catalysts and hierarchical Fe₂O₃ photoanodes through an oxygen vacancy self-healing process, which exhibited a remarkable improvement in PEC water oxidation activity. More specifically, the photocurrent density could be achieved up to 3.0 mA cm⁻² at 1.23 V vs. the reversible hydrogen electrode (V_RHE) under simulated sunlight (AM 1.5G, 100 mW cm⁻²), which is much higher than that of direct decoration of FeOOH catalysts (1.5 mA cm⁻²) and pristine Fe₂O₃ photoanodes (1.3 mA cm⁻²). Detailed experiments and theoretical calculations reveal that the preformed oxygen vacancies on Fe₂O₃ photoanode surfaces could efficiently facilitate the interfacial bonding with FeOOH catalysts, which significantly promote the charge separation and hole transport to participate in the water oxidation reaction. More importantly, these findings might provide a new insight into interface modulation of the photoanode/catalyst for highly efficient PEC water splitting.