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.