Shape-engineered yellow-emissive carbon quantum dots (Y-CQDs) with discernible edges were synthesized. Three-fold-symmetric benzene-1,3,5-triol was a suitable precursor for controlling the specific structure and shape of CQDs via dehydration-facilitated covalent polymerization in sulfuric acid within 90 min of a thermal reaction at 190 °C. The formation mechanism involves ring cyclization of benzene-1,3,5-triol via a six-membered fashion through elimination of the neighboring active -H and –OH groups. Binary heterostructure nanocomposites, comprising CdS-nanorods (NRs) and Y-CQDs, were prepared using simple sonication followed by solvent evaporation under stirring. The nanocomposite with 6 wt% YCQDs (CdS@Y-CQDs-6) exhibited the highest enhanced photocatalytic degradation of rhodamine B (RhB) with a degradation efficiency of 98% within 45 min, and the degradation rate constant was ~4.8 times higher than that of pristine CdS-NRs under visible light irradiation. The degradation of RhB is carried out through the formation of a green emissive intermediate N-deethylated RhB. The improved photocatalytic degradation performance of CdS@Y-CQDs nanocomposites is attributed to the formation of near-surface heterojunction of surface-adsorbed specific-shaped Y-CQDs, which can widen the range of light absorption and promote the separation of photogenerated electron-hole pairs in CdS-NRs by trapping and boosting the transfer of photo excited charge carriers over the surface.

合成了具有可识别边缘的形状工程化的黄色发射碳量子点（Y-CQDs）。三重对称苯-1,3,5-三醇是在190°C的热反应后90分钟内通过硫酸中的脱水促进共价聚合来控制CQD特定结构和形状的合适前体。形成机理涉及通过以下方法对苯-1,3,5-三醇进行环环化通过消除相邻的-H和-OH活性基团形成六元态。使用简单的超声处理，然后在搅拌下蒸发溶剂，即可制备出包含CdS-纳米级（NRs）和Y-CQDs的二元异质结构纳米复合材料。YCQDs为6 wt％的纳米复合材料（CdS @ Y-CQDs-6）表现出最高的罗丹明B（RhB）增强光催化降解性能，在45分钟内的降解效率为98％，降解速率常数约为4.8倍。可见光辐照下原始CdS-NRs的分子量。RhB的降解是通过形成绿色的发射性中间体N-去乙基RhB来进行的。CdS @ Y-CQDs纳米复合材料光催化降解性能的提高归因于表面吸附的异形Y-CQDs的近表面异质结的形成，