A Study on the UV Degradation Performance of Rhodamine B by Zn-TiO2 Photocatalysts and Cement Mortar-Based Zn-TiO2 Composites

Zn-TiO₂ composites were synthesized via a hydrothermal method, and their photocatalytic performance was optimized using an orthogonal design. Among the factors of hydrothermal temperature, reaction time, and Ti/Zn molar ratio, hydrothermal temperature showed the most significant influence on the photocatalytic performance of Zn-TiO₂. The Zn-TiO₂ obtained under the optimal conditions (120 °C, 10 h, and a Ti/Zn molar ratio of 100:5) exhibited the best photocatalytic performance, with a 26% improvement in the photocatalytic degradation efficiency of Rhodamine B (RB) compared to pure TiO₂ under identical conditions. The composition, morphology, and structure of the Zn-TiO₂ photocatalysts were characterized by XRD, SEM-EDS, N₂ adsorption-desorption, and XPS, thereby enabling analysis of the mechanism for the enhancement of its photocatalytic performance. In this work, air-entrained composite mortar (ACM) with a double-layer structure was designed as a contrast to conventional cement mortar (CM). Novel green building materials with pollutant-degradation capability were developed by loading Zn-TiO₂ and TiO₂ photocatalysts onto these different mortar surfaces. Photocatalytic tests and cyclic aging experiments demonstrated that the Zn-TiO₂/ACM achieved the superior degradation effect on the RB solution and maintained good catalytic stability. These findings suggest broad application prospects in the field of green building materials.