Pr-induced dual-site oxide pathway in BiFeO3 for enhanced alkaline water oxidation

Abstract

Rare-earth elements are effective modulators of electronic structures due to their unique electronic configurations. In particular, when occupying the A-site of transition metal perovskite ferrite oxides, rare-earth elements demonstrate notable catalytic performance in the oxygen evolution reaction (OER). In this study, the substitution with Pr³⁺ precisely modulated the A-site occupancy in BiFeO₃. We systematically investigated the effect of Pr doping concentrations on the adsorption and conversion of OER intermediates, aiming to elucidate the heteroatomic dual-site-driven oxide pathway mechanism (OPM). Density functional theory (DFT) simulations, in conjunction with experimental results, demonstrate that the appropriate incorporation of Pr enhances the overlap of the electronic density of states, modulates the d-band center, promotes the formation of *O radicals, and optimizes the adsorption of key reaction intermediates. Meanwhile, Pr-induced lattice distortion effectively reduces the distance between dual sites, thereby accelerating *O–O* coupling and shifting the OER mechanism toward a dual-site OPM dominated by the Pr/Bi and Fe sites. Notably, Bi_0.6Pr_0.4FeO₃@NF exhibits the best OER performance in 1.0 M KOH, with overpotentials of η₁₀ = 228 mV and η₅₀ = 309 mV, and a charge transfer resistance of only 0.828 Ω, and excellent durability exceeding 100 hours at a high current density of 100 mA cm⁻². This work provides a practical and effective strategy for improving the water oxidation performance of transition metal-based perovskite electrocatalysts.