Surface modification plays an important role in extending light absorption and enhancing the catalytic performance of semiconductor photocatalysts. However, most current studies focus on pre-modification of the semiconductors before reaction, while surface self-modification of catalyst during photocatalytic reaction process is often neglected. Here, we report the surface self-modification of TiO2 catalyst during photocatalytic oxidation of toluene under UV light irradiation, which changes the colour of TiO2 from white to yellow, and effectively extends its light absorption range into visible light region. The absorbed visible light is primarily released as thermal energy, significantly increasing the temperature of the catalytic system. Mechanistic studies reveal that the temperature elevation facilitates the separation of photogenerated charge carriers in TiO2 and promotes the generation of •O2−, consequently accelerating the surface redox reactions. The surface self-modified TiO2 exhibits an enhanced photothermal catalytic benzaldehyde generation of 4485 μmol g−1 h−1 under UV–visible light irradiation, which surpasses the UV-driven activity by a factor of 1.9. This study offers new perspectives on the surface modification of semiconductor photocatalysts during organic transformations. It is anticipated to trigger increased research attention to this effect, ultimately advancing solar-to-chemical energy conversion.

中文翻译：

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TiO2 的表面自改性，通过光热效应增强光催化甲苯氧化


表面改性在延长光吸收和增强半导体光催化剂的催化性能方面起着重要作用。然而，目前的大多数研究都集中在半导体反应前的预改性上，而光催化反应过程中催化剂的表面自改性往往被忽视。本文报道了 TiO2 催化剂在紫外光照射下光催化氧化甲苯过程中的表面自改性，使 TiO2 的颜色由白色变为黄色，并有效地将其光吸收范围扩展到可见光区域。吸收的可见光主要以热能的形式释放，显着提高了催化系统的温度。机理研究表明，温度升高促进了 TiO2 中光生载流子的分离，并促进了 •O2− 的产生，从而加速了表面氧化还原反应。在紫外-可见光照射下，表面自改性 TiO2 表现出增强的光热催化苯甲醛生成量为 4485 μmol g-1 h-1，比紫外线驱动的活性高出 1.9 倍。本研究为半导体光催化剂在有机转化过程中的表面改性提供了新的视角。预计它将引发对这种效应的更多研究关注，最终推动太阳能到化学能源的转换。