Fabrication of graphene modified CeO2/g-C3N4 heterostructures for photocatalytic degradation of organic pollutants

A specific type S-scheme photocatalyst CeO2@N-GO/g-C3N4 was successfully synthesized, resulting in a 2-mercaptobenzothiazole (MBT) degradation rate of 100%, which is more than twice that of g-C3N4 and CeO2. The improved degradation performance can be attributed to the introduction of N-graphene oxide (N-GO), which facilitates the electron transfer. Additionally, the unique Ce4+ → Ce3+ conversion property enhances the charge carrier utilization, and thereby the photocatalytic activity. Furthermore, theoretical calculations suggest the formation of an interfacial internal electric field (IEF) formed between CeO2 (the (200) and (311) planes) and g-C3N4 (the (002) plane) to enhance the delocalization of the charge carriers. Moreover, various photoelectrochemical analyses are employed for the in-depth mechanism on MBT degradation and IEF-induced S-scheme over CeO2@N-GO/g-C3N4, where the differential charge proves the electron transfer path from CeO2 to g-C3N4 that significantly prolongs its lifetime. The radical capture and electron spin resonance (ESR) results proved the existence of the active species of •OH, •O2−, and h+ in the S-scheme photocatalytic system.