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 photoelectrocheical 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.