TiO₂ catalysts were synthesized via simple sol–gel method using different carboxylic acids. The synthesized materials were characterized by UV–Vis spectroscopy (DRS), X-ray diffraction (XRD), N₂ physisorption and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the samples was evaluated in the degradation of phenol under visible and solar light. The prepared catalysts using the carboxylic acids showed an improvement in the characteristics of TiO₂. Particularly, the catalyst prepared with citric acid, showed a single pure anatase phase with a small crystallite size (of around 9.4 nm), larger surface area (81 m²/g) and narrower band gap (2.94 eV) compared to the non-modified TiO₂ and the reference Degussa P25. Moreover, the results showed that using citric acid, a high conversion of phenol under visible light of around 46% was achieved and a complete degradation under sunlight in a shorter time of around 90 min.

TiO ₂催化剂是通过简单的溶胶-凝胶法使用不同的羧酸合成的。合成材料通过紫外-可见光谱（DRS），X射线衍射（XRD），N ₂物理吸附和X射线光电子能谱（XPS）进行表征。通过可见光和太阳光下苯酚的降解来评估样品的光催化活性。使用羧酸制备的催化剂显示出TiO ₂特性的改善。特别是，用柠檬酸制得的催化剂显示出一个纯的锐钛矿相，与非碳酸氢盐相比，具有较小的微晶尺寸（约9.4 nm），较大的表面积（81 m ² / g）和较窄的带隙（2.94 eV）。改性TiO ₂和参考Degussa P25。此外，结果表明，使用柠檬酸，在约46％的可见光下苯酚的转化率高，并且在阳光下约90分钟的短时间内即可完全降解。