Fabrication and photocatalytic activity of graphitic-C3N4 quantum dots-decorated basic zinc carbonate prepared by a co-precipitation method.

Graphitic carbon nitride quantum dots (CNQDs) with a high quantum yield (up to 43%) were synthesized by incorporating the unique organic functional group of barbituric acid into the framework of the carbon nitride structure by supramolecular pre-organization. The CNQDs were introduced onto the surface of basic zinc carbonate (BZC) by co-precipitation. The resulting CNQDs/BZC composite showed that the degradation efficiency of tetracycline was 2.4 times higher than that of ZnO. The Z-scheme mechanism for the as-prepared sample was proposed for the enhanced photocatalytic degradation rate. The ˙O2- and ˙OH radicals played major roles due to the suitable bandgap. Finally, the formation and possible photocatalytic mechanisms of the CNQDs/BZC composite are proposed.