Construction and Photocatalytic Activity Study of Wide Bandgap Semiconductor Heterojunctions with γ-Al2O3/CeO2

Abstract

An one-step sol–gel method have been used to synthesize the Z-scheme γ-Al₂O₃/CeO₂ heterojunction with high hydrogen peroxide yield. Structural characterization confirmed that the γ-Al₂O₃/CeO₂ catalyst only contains two components, γ-Al₂O₃ and CeO₂, and with the increase of γ-Al₂O₃ content, only the crystalline size of the γ-Al₂O₃/CeO₂ catalyst was slightly changed. Element Mapping and optical property characterization confirmed that a special heterojunction was formed between γ-Al₂O₃ and CeO₂, and it had a high optical absorption coefficient in the wavelength range of 190–450 nm. The composition change of γ‑Al₂O₃ did not alter the optical band gap value of the γ-Al₂O₃/CeO₂ catalyst. When the flow rate of oxygen, catalyst content and pH value were 50 mL/min, 1.5 g/L, and 7, respectively, the hydrogen peroxide yield of the γ‑Al₂O₃/CeO₂ catalyst reached the maximum, with a concentration of 4678 μmol/g. Based on experimental data and band arrangement theory, a Z-scheme heterojunction of γ-Al₂O₃/CeO₂ was constructed. This breakthrough research provides technical support and experimental basis for the application of wide bandgap heterojunctions in the field of hydrogen peroxide production.