Preparation and Photocatalytic Performance Study of TiO₂-TMP Composites Under Effect of Crystal Structure Modulation

Nano-titanium dioxide (TiO₂) is currently the most widely studied photocatalyst. However, its rapid recombination of photogenerated carriers and narrow range of light absorption have limited its development. Crystal form regulation and polymer modification are important means for improving the photocatalytic activity of single-phase materials. In this paper, TiO₂ materials of different crystal forms were prepared by changing the synthesis conditions, and they were compounded with trimesoyl chloride-melamine polymers (TMPs) by the hydrothermal synthesis method. Then, their photocatalytic performance was evaluated by degrading methylene blue (MB) under visible light. The mechanisms of influence of TiO₂ crystal form on the photocatalytic activity of TiO₂-TMP were explored by combining characterization and theoretical calculation. The results showed that the TiO₂ crystal form, through interface interaction, the built-in electric field intensity of the heterojunction, and active sites, affected the interface charge separation and transfer, thereby influencing the photocatalytic activity of TiO₂-TMP. In the 4T-TMP photocatalytic system, the degradation rate of MB was the highest. These studies provide theoretical support for understanding the structure-property relationship of the interfacial electronic coupling between TiO₂ crystal forms and TMP, as well as for developing more efficient catalysts for pollutant degradation.