Piezo-Photocatalytic Hydrogen peroxide Generation over Nitrogen doped Strontium titanate

Nitrogen-doped SrTiO 3 (N:STO) was synthesized via a reflux-calcination route and evaluated as a piezo-photocatalyst for sustainable H 2 O 2 production driven by coupled light irradiation and ultrasonic excitation. Nitrogen incorporation tailors the electronic structure of STO by narrowing the optical bandgap and generating defect-rich surfaces, thereby improving visible-light utilization, charge separation, and interfacial charge transfer. The optimized 5% N:STO achieves photocatalytic H 2 O 2 production rates of 388.53 μmol g -1 h -1 under solar irradiation and 278.53 μmol g -1 h -1 under visible light, exceeding pristine STO at 175.54 and 21.06 μmol g -1 h -1 , respectively. Under piezo-photocatalytic operation, a pronounced synergy between photoexcitation and ultrasound-induced polarization boosts H 2 O 2 productivity to 9043.89 μmol g -1 h -1 under solar light and 4995.90 μmol g -1 h -1 under visible light, nearly one order of magnitude higher than pristine STO under identical conditions. Mechanistic evaluation supports that H 2 O 2 formation predominantly proceeds through a selective two-electron oxygen reduction pathway, with an additional contribution from two-electron water oxidation, while hydroxyl-radical routes are minor. The catalyst maintains nearly constant activity over repeated cycles, demonstrating robust stability under simultaneous photo and mechanical excitation.