Preparation and Photocatalytic Properties of Al2O3–SiO2–TiO2 Porous Composite Semiconductor Ceramics

Abstract

Titanium dioxide (TiO₂) is widely employed in the catalytic degradation of wastewater, owing to its robust stability, superior photocatalytic efficiency, and cost-effectiveness. Nonetheless, isolating the fine particulate photocatalysts from the solution post-reaction poses a significant challenge in practical photocatalytic processes. Furthermore, these particles have a tendency to agglomerate into larger clusters, which diminishes their stability. To address this issue, the present study has developed Al₂O₃-SiO₂-TiO₂ composite semiconductor porous ceramics and has systematically explored the influence of Al₂O₃ and SiO₂ on the structure and properties of TiO₂ porous ceramics. The findings reveal that the incorporation of Al₂O₃ augments the open porosity of the ceramics and inhibits the aggregation of TiO₂, thereby increasing the catalytic site and improving the light absorption capacity. On the other hand, the addition of SiO₂ enhances the bending strength of the ceramics and inhibits the conversion of anatase to rutile, thereby further enhancing its photocatalytic activity. Consequently, at an optimal composition of 55 wt.% Al₂O₃, 40 wt.% TiO₂, and 5 wt.% SiO₂, the resulting porous ceramics exhibit a methylene blue removal rate of 91.50%, and even after undergoing five cycles of testing, their catalytic efficiency remains approximately 83.82%. These outcomes underscore the exceptional photocatalytic degradation efficiency, recyclability, and reusability of the Al₂O₃-SiO₂-TiO₂ porous ceramics, suggesting their substantial potential for application in the treatment of dye wastewater, especially for the removal of methylene blue.