Elaborative Defect Design on G-C3n4 Toward Efficient Photocathodic Protection for 304 Stainless Steels

Highlights• Precise control on defective g-C3N4 with both S dopant and C vacancies (CN-ES) were archived.• CN-ES with both shallow defect states and optimized surface states favored enhanced solar harvesting and efficient photocarrier separation in bulk-phase and on surface.• CN-ES exhibited a superior PCP performance toward 304 stainless steels with an open circular potential (OCP) of -0.643 V and an outstanding OCP retention rate of 86.9% within 7200 s.