Tunable Catalytic Performance of Pd-Doped Carbon Dots for Catalytic Polymerization of Phenylacetylenes via Modification of Surface Functional Groups

The catalytic activity of traditional nitrogen-ligand Pd catalysts can be tuned by adjusting the polarity of the substituents on the ligands. Similarly, in this work, we achieved surface polarity regulation of Pd-doped carbon dots (CDs) by adjusting the carbon source, thereby enabling the modulation of their catalytic performance. Three types of CDs (CDs1–CDs3) were prepared using ortho-, meta-, and para-phenylenediamine as carbon sources, doped with palladium, via a one-step hydrothermal method (in H2O, 200 °C, and 6 h). The resulting three CDs exhibited similar ellipsoidal morphology, elemental composition, structure, and trace amounts of Pd. CDs1–CDs3 were capable of catalyzing the polymerization of phenylacetylene derivatives. Notably, the content of surface polar groups in CDs1–CDs3 gradually increased (CDs1 < CDs2 < CDs3). When used to catalyze the polymerization of phenylacetylene derivatives, the catalytic performance of CDs1–CDs3 improved progressively, with increases in molecular weight, yield, and structural control of the resulting products. Furthermore, the different structures of the three types of CDs also influenced their luminescent properties, with CDs1 emitting blue light, CDs2 emitting green light, and CDs3 emitting red light. This work demonstrates that the catalytic performance of CDs can be controllably adjusted when used in catalytic reactions.