Synthesis of In-Modified TiO2 Composite Materials from Waste Tobacco Stem Silk and Study of Their Catalytic Performance under Visible Light

Abstract

Titanium dioxide (TiO2) catalysts are primarily utilized under ultraviolet light, and their potential in industrial applications remains largely untapped. To address this issue, our study uses a one-pot impregnation method to prepare a series of In-TiO2/TSS(X) (TSS, Tobacco stem silk. X, the molar ratio of In/Ti) catalysts. Among them, the degradation performance of the In-TiO2/TSS(2.0) material increased from 13.8% for TiO2 to an impressive 92.9%. By establishing a first-order kinetic model, it was determined that the degradation performance of the In-TiO2/TSS(2.0) material surpassed that of TiO2 by a factor of 24. Structural characterization revealed that the introduction of tobacco stem silk templates did not alter the crystal phase of TiO2 and that the main component of the catalyst remained TiO2. Not only that, an O–In structure formed on the surface of the TiO2, leading to a significant increase in the material’s specific surface area. Furthermore, principle tests were conducted, revealing significant enhancements in its light absorption capacity, intensity, and photocurrent density. Through active species trapping experiments, it was observed that, in the photocatalytic degradation process of this catalyst series, holes (h+) played the primary role, while the hydroxyl ion (·OH) and superoxide ion (·O2−) acted as auxiliary species.