Preparation and Photocatalytic Performance of Nano-TiO2Composite Decorative Panels Using the Multilayer Method

Self-cleaning decorative panels rely on the presence of photocatalytic nano-TiO2(NT) to effectively degrade pollutants and achieve a stable decoration effect. However, the method of directly mixing NT with raw materials is limited by its high NT dosage and poor utilization. This study proposes a novel NT composite decorative panel prepared by the multilayer method, which is suitable for architectural decoration and reduces the NT content to achieve stable self-cleaning performance. The study investigates the effects of the NT content, NT particle size, and thickness of the NT-surface layer on the mechanical properties and photocatalytic performance of the panels. The results reveal that an appropriate amount of NT can fill the pores in the cement stone, improve the microstructure of the hydration system, and enhance the compressive strength of the specimens. The compressive strength of the decorative panels that are produced using the multilayer method decreases when the NT-surface layer thickens. The optimal thickness of the NT-surface layer is determined to be 1/7 of the thickness of the panels. Additionally, the optimal NT particle size and NT content in the NT-surface layer are 25 nm and 5%, respectively. Upon exposure to UV lamp irradiation, the decorative panels exhibit a degradation rate of 94% for nitric oxide (NO) and 88% for rhodamine B (RhB). The NO degradation rate of the decorative panels initially increases and subsequently decreases with the increase in moisture content, and the optimal moisture content is approximately 1.2%. Insufficient or excessive water can reduce the photocatalytic efficiency of the decorative panels. When the NO concentration increases, the degradation rate of the decorative panels decreases, but the total amount of NO degradation increases. After 6 months of exposure to outdoor conditions, the NO degradation rate of the decorative panels decreased by 15% but remained high at 80%.