In this work, we have developed and optimized TiO₂ nanoparticles decorated with carbon quantum dots to examine its potential use in the photocatalytic oxidation of aromatic ring containing gas-phase mixed volatile organic compounds, e.g., benzene, toluene, and p-xylene. Carbon quantum dots decorated TiO₂ demonstrated good photodegradation efficiency in contrast to pure TiO₂ under UV-visible light illumination. For example, with 0.5 wt% carbon quantum dots decorated on TiO₂, 64% of the mixed volatile organic compounds were photodegraded, while pure TiO₂ only exhibited 44% of the photodegradation efficiency. Also, the carbon quantum dots (0.5 wt%)/TiO₂ nanocomposite demonstrated considerable photocatalytic activity within the visible region. On the other hand, pure TiO₂ remained inactive within the visible region. The density functional theory study of the carbon quantum dots/TiO₂ interface revealed that C 2p states of carbon quantum dots incorporated new energy states around the Fermi level near the lowest conduction band. This might be accountable for the improved charge separation process and better conductivity of the photogenerated electrons. The improved photocatalytic performance of the carbon quantum dots/TiO₂ nanocomposites can be attributed to good light harvesting within the UV-visible region, charge separation, and adsorption capability.

在这项工作中，我们开发并优化了装饰有碳量子点的TiO ₂纳米颗粒，以研究其在含芳香环的气相混合挥发性有机化合物（如苯，甲苯和对二甲苯）的光催化氧化中的潜在用途。与纯TiO ₂在紫外可见光照射下相比，碳量子点装饰的TiO ₂具有良好的光降解效率。例如，在TiO ₂上装饰有0.5 wt％的碳量子点时，64％的混合挥发性有机化合物被光降解，而纯TiO ₂仅表现出44％的光降解效率。此外，碳量子点（0.5 wt％）/ TiO ₂纳米复合材料在可见光区域内表现出相当大的光催化活性。另一方面，纯TiO ₂在可见光区域内保持惰性。碳量子点/ TiO ₂界面的密度泛函理论研究表明，碳量子点的C 2p状态在最低导带附近的费米能级附近结合了新的能量态。这可能是由于改进了电荷分离过程并提高了光生电子的电导率。碳量子点/ TiO ₂纳米复合材料的改善的光催化性能可归因于在紫外可见区域内良好的光收集，电荷分离和吸附能力。