Modulating charge kinetics in CDs/CTF S-scheme hybrids for enhanced H2O2 photosynthesis

The demand for green production of hydrogen peroxide (H₂O₂) has triggered extensive research on photocatalytic synthesis, but there are still problems of low catalytic efficiency. Herein, N, S co-doped carbon dots (N, S-CDs) were anchored on the covalent triazine frames (CTFs) to successfully form the N, S-CDs/CTFs S-scheme heterojunction by a simple hydrothermal method for achieving the optimal photocatalytic H₂O₂ production rate of 10,350 μM g⁻¹ h⁻¹ in pure water. Between the interface of N, S-CDs and CTFs, five- or six-membered nitrogen- and sulfur-containing heterocycles are linked together to accelerate the electron transfer rate through the conjugation effect. In addition, the S-scheme heterostructure can effectively form an internal electric field (IEF) at the interface, which can promote the separation of electrons and holes. For practical application, the H₂O₂ produced by the N, S-CDs/CTFs composite photocatalytic system can also be used for photocatalytic antimicrobial treatments, which achieved a bactericidal rate of 86% against E. coli, 28% higher than that of pure CTFs. The design displays great potential in the fields of photocatalytic H₂O₂ generation and photocatalytic antimicrobial, and also makes the photocatalytic antimicrobial technology more stable and efficient. Meanwhile, it also expands a new direction for the application of homogeneous CDs in photocatalysis.