In this work, several efficient heterostructured nanocomposites with enhanced CO₂ photoreduction activity were successfully constructed by anchoring carbon quantum dots onto TiO₂ using a facile microwave assisted synthesis strategy. The carbon quantum dots obtained by microwave treatment of thiourea and citric acid acted as a sensitizer in the composites to enhance light absorption. The high-resolution transmission electron microscopy (HR-TEM) revealed that a closely integrated interface between carbon quantum dots and TiO₂ nanosheets was formed in the heterostructured nanocomposites. Furthermore, the photogenerated charge transfer and separation in the heterogeneous nanocomposites were demonstrated to be significantly improved when compared with that in pristine TiO₂. Consequently, a remarkable enhancement of photocatalytic activity evaluated for CO₂ photoreduction under simulated solar light irradiation can be found in the nanocomposites. Maximum CH₄ and CO yields of 0.769 and 1.153 μmol, respectively, have been obtained from the photoreduction after one hour irradiation without any noble metal loaded on photocatalyst. The amounts of CH₄ and CO generated over nanocoposite are 7.79 and 7.61 times as high as those on pristine TiO₂. This encouraging performance in CO₂ photoreduction shows that these nanocomposites might be a prospective material in environmental protection and energy conversion.

在这项工作中，通过使用便捷的微波辅助合成策略将碳量子点固定在TiO ₂上，成功构建了几种具有增强的CO _2光还原活性的高效异质结构纳米复合材料。通过硫脲和柠檬酸的微波处理获得的碳量子点在复合物中用作敏化剂以增强光吸收。高分辨率透射电子显微镜（HR-TEM）表明，碳量子点与TiO ₂之间紧密结合的界面在异质结构的纳米复合材料中形成纳米片。此外，与原始的TiO ₂相比，在非均相纳米复合材料中的光生电荷转移和分离被证明得到了显着改善。因此，可以在纳米复合材料中发现在模拟的太阳光照射下评估用于CO ₂光还原的光催化活性的显着提高。在没有任何贵金属负载在光催化剂上的情况下，经过一小时的照射后的光还原，分别获得的最大CH ₄和CO产量分别为0.769和1.153μmol。纳米复合材料上生成的CH ₄和CO的量分别是原始TiO _2的7.79和7.61倍。CO _2光还原的令人鼓舞的性能表明，这些纳米复合材料可能是环保和能量转化的潜在材料。