CaSnO₃/g-C₃N₄ S-scheme heterojunction photocatalyst for the elimination of erythrosine and eriochrome black T from water under visible light

Heterojunction photocatalysts are critical for facilitating long-term photoinduced carrier separation and enhancing single photocatalyst photocatalytic performance. As part of the present study, calcium stannate (CaSnO₃, CSO) was produced using a simple and low-cost auto-combustion method, and CaSnO₃/g-C₃N₄ (CSO/CN) nanocomposites with different CSO contents were prepared using a co-precipitation method aided by ultrasound. An investigation of the erythrosine (ER) and eryochrom black T degradation capacities of CSO, CN, and several CSO/CN nanocomposites was carried out. According to the results, the degradation rate was affected by the dye type, the amount of CSO, the amount of catalyst, as well as the concentration of ER. With 70 mg of CSO/CN (0.1:1), the CSO/CN nanocomposite with 10% CSO demonstrated the greatest efficiency, which resulted in 86.2% of ER being destroyed. Scavenger experiments revealed that superoxide radicals exhibited exceptional characteristics in photoreactions. A higher proficiency (86.2%) contributed the highest rate constant (k = 0.022 min⁻¹), according to the kinetics study. As a result of these findings, there is potential for CSO/CN nanocomposite to be used in water treatment applications.