Abstract:

The narrow light absorption range of photocatalysts and the rapid complexation of photogenerated electron-hole pairs are important factors affecting the photocatalytic hydrogen production performance. Doping modification is an effective method to improve it. The C/g-C₃N₄-TiO₂ composites were synthesized by hydrothermal and calcination methods, and the C-doped g-C₃N₄ not only modulated the energy band structure of g-C₃N₄, but also significantly enhanced the visible light absorption ability of TiO₂. Then the photocatalytic performance of C/g-C₃N₄-TiO₂ with different C/g-C₃N₄ contents in decomposing water to hydrogen was further explored. The experimental results showed that the introduction of C/g-C₃N₄ significantly enhanced the absorption ability of TiO₂ in the visible region and broadened its photoresponse range. When the mass ratio of C/g-C₃N₄-TiO₂ was 0.1, the ternary complex showed the highest hydrogen production rate [4.66 mmol/(g·h)], which was 2.31 times that of TiO₂ and 7.17 times that of C/g-C₃N₄. And it still has certain enough stability after seven cycles. This is mainly due to the synergistic effect between C/g-C₃N₄ and TiO₂, which effectively promotes the separation and transport of photogenerated carriers and reduces the complexation of electron-hole pairs, thus improving the photocatalytic efficiency. Therefore, by rationally designing and optimizing the composite structure of photocatalysts, their performance in the process of water splitting for hydrogen production can be significantly enhanced, providing new insights and directions for the development of efficient photocatalysts.

Key words: catalyst, g-C₃N₄, TiO₂, photocatalysis, hydrogen production

摘要：

光催化剂的光吸收范围窄以及光生电子-空穴对的快速复合是影响光催化制氢性能的重要因素，通过掺杂改性可有效改善其催化性能。利用热缩合和煅烧法制备出C/g-C₃N₄-TiO₂复合材料，C修饰g-C₃N₄不仅调控了TiO₂的能带结构，还显著增强了TiO₂对可见光的吸收能力。进一步探究了不同C/g-C₃N₄含量的C/g-C₃N₄-TiO₂分解水制氢的光催化性能。实验结果表明，C/g-C₃N₄的引入显著增强了TiO₂在可见光区域的吸收能力，并拓宽了其光响应范围。当C/g-C₃N₄-TiO₂质量比为0.10时，三元复合物的产氢速率最高[4.66 mmol/(g·h)]，是TiO₂的2.31倍，是C/g-C₃N₄的7.17倍，且经过七次循环后，仍具有较好的稳定性。这主要得益于C/g-C₃N₄与TiO₂之间的协同作用，有效促进了光生载流子的分离和传输，减少了电子-空穴对的复合，从而提高了光催化产氢效率。因此，通过合理设计和优化光催化剂的复合结构，可以显著提升其在水分解制氢过程中的性能，为高效光催化剂的开发提供新的思路和方向。

关键词: 催化剂, g-C₃N₄, TiO₂, 光催化, 制氢