Novel S-scheme loofah biochar/MoS2/g-C3N4 heterojunctions with efficient photogenerated carrier separation and transfer capability: Effect, mechanism and application

The construction of S-scheme heterojunctions has drawn widespread attention within the photocatalysis field due to their capacity for efficient separation of photogenerated carriers, leading to excellent photo-oxidation-reduction performance. Herein, a novel S-scheme loofah biochar/MoS 2 /g-C 3 N 4 (LB/MS/CN) heterojunction was successfully constructed by ultrasonication in 50 % ethyl alcohol and heat treatment in N 2 atmosphere. Degradation experiments showed that the 5 % LB/MS/CN ternary photocatalyst had optimal photocatalytic efficiency (96.4 %) for the degradation of rhodamine B (RhB), and the reaction rate (k) of this photocatalyst (0.05420 min −1 ) was 5.4 times that of unmodified CN (0.01001 min −1 ). Ultraviolet-visible diffuse reflectance spectra, Mott-Schottky, and free radical trapping experiments suggested that the photogenerated carriers in LB/MS/CN were transferred through the S-scheme structure. Consequently, the co-catalytic action of LB and the synergistic impact of the heterojunction structure between CN and MS led to a reduced photogenerated carrier recombination rate. Furthermore, LB/MS/CN had outstanding stability and the capacity to maintain RhB degradation performance under various environmental conditions (H 2 PO 4 − , NO 3 − , SO 4 2− , HCO 3 − , NaCl, humic acid (HA), and real water), showing good promise for practical applications. Thus, this work provides a possible strategy for purifying wastewater under visible light.