Difunctional carbon quantum dots/g-C3N4 with in-plane electron buffer for intense tetracycline degradation under visible light: Tight adsorption and smooth electron transfer

In this study, a lateral heterostructures material (LCCN) of carbon quantum dot (CQDs) and carbon nitride (CN) was designed via the thermal polymerization of freeze-dried precursor. The special lateral heterostructures (LHSs) increased the bond length of O–O to fleetly active dissolved oxygen (DO), which exhibits 14-fold increased for tetracycline (TC) visible-light degradation compared to CN. In addition, the electrons of activated DO came from both TC and LCCN, which trapped the oxygen to generate multitudinous superoxide radical (•O2–), while the hole (h+) showed a negligible role in photocatalytic system. A rapid electron transfer channel was speculated between TC and photocatalyst by experiments and density functional theory. Furthermore, DFT and LC/MS predicted four degradation pathways of TC with the Fukui index (f0), and LCCN exhibited a favorable hinder on various environmental interferences. This work presented a novel perspective for the relationship of pollutant and material in photocatalysis.