Fine-Tuning Surface Properties of Perovskites via Nanocompositing with Inert Oxide toward Developing Superior Catalysts for Advanced Oxidation

Cost-effective, stable, and highly efficient heterogeneous catalyst is the key challenge for wastewater treatment based on Fenton-like advanced oxidation processes. Perovskite oxides offer new opportunities because of their versatile compositions and flexible physiochemical properties. Herein, a new strategy is proposed that is different from the frequently used alien-metal doping, to tune surface properties of perovskite oxides by nanocompositing perovskite with inert oxide, resulting in improved activity and stability for catalytic oxidation. By in situ modification of LaFeO₃ with inert La₂O₃ oxide through one-pot synthesis, several important surface properties such as surface defects, H₂O₂ adsorption capacity, Fe²⁺ concentration, and charge-transfer rate were improved, as well as resistance against iron leaching. In performance evaluation, among the various materials, La_1.15FeO₃ (L_1.15FO) composite shows the highest Fenton activity (0.0402 min⁻¹) for activating H₂O₂ to oxidize methyl orange, 2.5 times that of the pristine LaFeO₃. Notably, in situ electron paramagnetic resonance analysis and radical scavenging tests unveil a faster generation of singlet oxygen as the dominant reactive species over L_1.15FO, consequently a novel non-radical activation mechanism is proposed. Such improved performance is assigned to the strong coupling effect between the nanosized LaFeO₃ and La₂O₃ in the hybrids, which fine-tune the surface properties of LaFeO₃ perovskite as superior Fenton catalysts.