In situ generation of H2O2 over Ce-doped BaTiO3 catalysts for enhanced piezo-photocatalytic degradation of pollutants in aqueous solution

Abstract

Piezo-photocatalytic technique is a new-emerging strategy to promote the separation of electron-hole pairs and thus enhance catalytic performance. Here, a series of Ce-doped barium titanate (BTCe-x) composites were prepared by sol-gel/hydrothermal method, the applied in the removal of organic dyes in water under the piezo-photocatalytic effect. In this study, the BTCe-0.025 exhibit superior catalytic performance for different types of organic dyes (Acid Fuchsin (AF), Crystal Violet (CV), Congo Red (CR), Acid Chrome Blue K (ABK), Methylene Blue (MB), and Methyl Orange (MO)). For example, the degradation efficiency of AF, CR, and ABK is 99.1 %, 99.4 %, and 88.6 %, respectively, at a concentration of 10 mg/L for 10 min under visible light and ultrasonic vibration. This is attributed to the narrowing of the band gap and the negatively shifted conduction band under Ce doping, improving the utilization of visible light and enhancing the ability of O2 to reduce to ·O2–. Additionally, O2 in an aqueous solution generates H2O2 in situ and can react with Fe(II) to generate strongly oxidizing·OH radicals, which can greatly enhance the oxidation ability of organic pollutants. This work provides a new and efficient strategy for developing high-efficiency piezo-photocatalyst materials in removing pollutants from wastewater.