Surface modification of g-C3N4 for enhanced photocatalytic activity via a simple illumination in pure water

Abstract

The surface of graphitic carbon nitride (g-C3N4) is decisive in its photocatalytic performance because the critical processes including pollutants adsorption, interfacial charge transfer, and redox reaction etc, readily take place on its surface. In this study, a novel surface functionalization strategy was developed to introduce hydroxyl groups on the surface of g-C3N4 through a simple illumination modification in pure water. The specific surface area and morphology of g-C3N4 did not show significant changes after light irradiation modification, but there were significant differences in the composition of surface functional groups, surface charge properties, and photocatalytic activities. A series of characterization results indicated that hydroxyl groups introduction on the surface of g-C3N4 could significantly enhance surface electronegativity, accelerate photogenerated charge carriers separation and transfer, and increase O2•- radicals generation, thereby improving the highly selective adsorption and photocatalytic degradation performance of g-C3N4 for cationic methylene blue (MB) wastewater treatment. This work provides an effective strategy for fabricating efficient g-C3N4 photocatalysts for different kinds of organic wastewater treatment via simple surface modification.