Cu-doped Ba0.5Sr0.5FeO3-δ for electrochemical synthesis of hydrogen peroxide via a 2-electron oxygen reduction reaction†

Electrochemical synthesis of hydrogen peroxide (H₂O₂) via a two-electron (2e^–) oxygen reduction reaction (ORR) has emerged as a sustainable synthesis route compared to the anthraquinone oxidation synthesis process. Ba_0.5Sr_0.5Fe_(1-x)Cu_xO_3-δ perovskite is a particularly interesting electrocatalyst for ORR applications owing to its doping flexibility. In this study, we use experimental and computation approaches to study Ba_0.5Sr_0.5FeO_3-δ with and without copper doping at the B-site for 2e^– ORR. Our electrochemical measurements in oxygen-saturated alkaline solution show that the selectivity of perovskite electrocatalyst increases from 30% to 65% with (0.05) copper doping in the B-site and the onset potential is decreased. Density functional theory calculations are used to unravel the role of copper in driving high activity and selectivity toward 2e^– ORR. Site-specific engineering of Ba_0.5Sr_0.5FeO_3-δ by copper doping in the B-site exposed unique adsorption sites with improved activity and selectivity for H₂O₂ formation.