Construction of novel Fe6W18O70/In2WO6/Ag-doped g-C3N4 ternary heterojunction photocatalyst for photodegradation of various environmental contaminants

Nowadays, nitrate, carbon dioxide, and organic contaminants are common pollutants that threaten the preservation and security of the global environment. Photocatalytic removal is one of the efficient, low cost, and safe approaches to remove these contaminants. The target of this work is of synthesis of Fe 6 W 18 O 70 polyoxometalate (metallic photocatalyst assistance), In 2 WO 6 binary perovskite (basic photocatalyst), and Ag-doped g-C 3 N 4 (non-metallic photocatalyst assistance) as a novel high-performance perovskite photocatalyst to removal of nitrate, carbon dioxide, and industrial dyes pollutants by exposure to visible radiation. The Fe 6 W 18 O 70 polyoxometalate/In 2 WO 6 / Ag-doped g-C 3 N 4 heterojunction photocatalyst was characterized by XRD, SEM, and EDAX/Mapping analysis. In addition, the influence of the effective factors including reaction medium pH, contact time, catalyst amount, and pollution values on the photocatalytic performance of the Fe 6 W 18 O 70 polyoxometalate/In 2 WO 6 /Ag-doped g-C 3 N 4 heterojunction photocatalyst was evaluated. The photocatalytic activity of the Fe 6 W 18 O 70 polyoxometalate/In 2 WO 6 /Ag-doped g-C 3 N 4 photocatalyst was optimized by assessing the effect of reaction medium pH, contact time, catalyst value variations, and pollution amounts. Considerably, the Fe 6 W 18 O 70 polyoxometalate/In 2 WO 6 /Ag-doped g-C 3 N 4 nanocomposites illustrated increased photodegradation efficiency by degrading over 90% of Rhodamine B cation dye, 90% of Eriochrome black T anion dye, 75% of nitrate, 80% of carbon dioxide, and 77% of sulfide contaminants. The obtained results illustrated that the Fe 6 W 18 O 70 polyoxometalate/In 2 WO 6 /Ag-doped g-C 3 N 4 energy band dap reduced to less than 3.0 eV (~ 2.5 eV). Finally, the Fe 6 W 18 O 70 polyoxometalate/In 2 WO 6 /Ag-doped g-C 3 N 4 nanocomposite showed structural stability and reusability even after 5 cycles of continuous use.