Perovskite-type SrFeO3/g-C3N4 S-scheme photocatalyst for enhanced degradation of Acid Red B

Semiconductor photocatalysis is extensively used as a feasible solution of water pollution treatment for the removal of hazardous organic pollutants from wastewater. In this research, a perovskite-type SrFeO 3 /g-C 3 N 4 composite was successfully synthesized by simple calcination method. The properties such as crystal structure, surface chemical composition, micromorphology and optical properties of the composite materials were characterized by XRD, FT-IR, SEM, EDS, XPS, UV–Vis DRS and PL techniques. The photocatalytic performance of samples was investigated by degrading Acid Red B under UV light irradiation, meanwhile, we optimized the preparation conditions of the binary composites such as the mass ratio of g-C 3 N 4 to SrFeO 3 , calcination temperature and calcination time, and explored the effect of operating parameters on the efficiency of photocatalytic degradation. The results showed that when the mass ratio of g-C 3 N 4 to SrFeO 3 was 3:2, the calcination temperature was 500 °C and the calcination time was 3 h, the synthesized SrFeO 3 /g-C 3 N 4 could reach the best photocatalytic activity, which displayed 80.2% degradation efficiency under UV irradiation at 256 nm, the rate was about 3.68, 1.36 and 1.23 times higher than that of pure SrFeO 3 , g-C 3 N 4 and uncalcined SrFeO 3 /g-C 3 N 4 , respectively. Furthermore, the cyclic tests exhibited satisfactory reusability and stability of SrFeO 3 /g-C 3 N 4 composite after five cycles, the photocurrent and PL tests proved the high separation efficiency of photogenerated electrons and holes and the high responsivity of the composite, the active species scavenger experiment indicated that •O 2− played a major role in the photocatalytic reaction. Finally, it was elucidated that the possible mechanism for the enhanced photocatalytic activity of perovskite-type SrFeO 3 /g-C 3 N 4 photocatalysts. • A perovskite-type SrFeO 3 /g-C 3 N 4 composite was successfully synthesized via simple calcination method. • SrFeO 3 /g-C 3 N 4 photocatalyst exhibited superior photocatalytic performance on Acid Red B degradation. • The operating parameters of Acid Red B photocatalytic degradation were systematically studied. • The regioselectivity of active species for attacking the Acid Red B molecules was predicted by condensed Fukui function. • A possible mechanism for the enhanced photocatalytic activity of SrFeO 3 /g-C 3 N 4 was proposed.