Surface-engineering strategies for g-C3N4 as efficient visible-light photocatalyst

Metal-free polymeric graphitic carbon nitride (for simplicity, g-C3N4) is recognized as promising visible-light photocatalyst for solar-fuels production and environmental remediation. To effectively improve the photocatalytic performance of g-C3N4, diverse strategies have been developed in recent years. Here, three typical surface-engineering strategies for g-C3N4 have been reviewed, which include (i) to dope nonmetals to extend the visible light absorption by creating surface states; (ii) to couple nanosized metal oxides onto the surface of g-C3N4 for enhancing the charge separation and (iii) to modify the surface of g-C3N4 with inorganic acids for promoting the O2 adsorption. Finally, this perspective highlights crucial issues that should be addressed in the future in the aforementioned.