Engineering oxidative desulfurization of dibenzothiophene under visible light over novel Ag3PO4/g-C3N4/CuInS2 ternary S-scheme photocatalyst

• Ternary bond S-scheme Ag3PO4/g-C 3 N 4 /CuInS 2 was successfully synthesized. • AGC-CQD achieved 97.69 % dibenzothiophene removal after 100 min. • CQD enhanced the electron transfer and reaction rate by 2.17 times. • AGC was integrated with CQD for S-scheme mechanism charge transfer. Fuels containing sulfur compounds are considered the main cause of SO x emissions leading to acid rain, so management policies are gradually being tightened to reduce sulfur content in fuels to below 10 ppm or even sulfur-free. However, aromatic compounds containing sulfur in fuels cannot be eliminated by conventional methods. In this study, a third-order S-scheme photocatalyst Ag 3 PO 4 /GCN/CuInS 2 integrated with carbon quantum dots (CQD, AGC-CQD) was successfully synthesized for the first time using an efficient microwave-assisted method. Influence of Ag 3 PO 4 content on the surface area, visible light absorption, electron-hole recombination rate, electron separation ability, and charge transfer within the AGC-CQD was thoroughly investigated. 30 %AGC-CQD material shows the ability to 97.69 % of dibenzothiophene (DBT) removal after 100 min of visible light irradiation, with a reaction rate constant 2.17 times greater than that of the pure 30 %AGC. The impact of various factors, including the amount of Ag 3 PO 4 , O/S ratio, DBT concentration, photocatalyst dosage, and catalyst reusability, on the efficiency of the photocatalytic process was evaluated. The charge transport pathway is determined through electron density and reactive species trapping experiments. These findings demonstrate the high potential for effective application of AGC-CQD photocatalyst in the production process of low-sulfur fuel.