Photocatalytic oxidative desulfurization and denitrogenation for fuels in ambient air over Ti3C2/g-C3N4 composites under visible light irradiation

MXene Ti3C2 modified g-C3N4 composites were prepared and used in photocatalytic oxidative denitrogenation and desulfurization under visible light. The photocatalysis system adapted to oxidation of small molecular pyridine and thiophene for fuels in the ambient air without adding extra H2O2 or pure O2 oxidants. Structural and photoelectric properties of the photocatalysts were characterized and compared. In an optimal composite, g-C3N4 nanosheets were successfully intercalated by Ti3C2 layers to form an interfacial effect and heterojunction. Intercalation effect accelerated the photogenerated electrons transferring from g-C3N4 to Ti3C2, and inhibited the recombination of electron-hole pairs. Ti3C2/g-C3N4 composite exhibited enhanced photocatalytic performance, high mineralization efficiency, and good recyclability in the removal of pyridine and thiophene. Mechanism and DFT studies proposed that the holes acted as the major active species for the photocatalysis procedures to form the reactant intermediates, while the electrons and O2 generated superoxide radicals provided a promotion effect on the final conversions.