TiO₂-chabazite semiconductor composites for photocatalytic degradation of rhodamine under sunlight irradiation

In this work, natural zeolite chabazite was employed to obtain semiconductor composites by mixing with commercial and sol-gel processed, anatase phase TiO₂ powders. The TiO₂-chabazite semiconductor composites were prepared by mixing the powders and subsequently milling at high-energy or stirring in aqueous solution at acid pH. The crystalline and morphological characteristics of the semiconductor composites were analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results show the polycrystalline character of the composites with good synergy between the phases. The different semiconductor composites were also tested and compared as photocatalysts in the photodegradation of rhodamine 6G in aqueous solutions under sulight irradiation. The photocatalytic properties of the semiconductor composites depend mainly on the quality of the TiO₂ semiconductor, with the commercial one yielding better photocatalysts. The adsorption properties of chabazite aid the photocatalysis process by accumulating rhodamine molecules near TiO₂ and allowing deeper penetration of sunlight in the solution. Both high-energy milled and acid route processed, commercial TiO₂–based composites produced better results for the rhodamine photodegradation under sunlight irradiation. The percent reduction of rhodamine in solution after 90 min produced by these semiconductor composites was 97.9 and 96.8%, respectively.