Fabrication and characterization of ZnGa_1.01Te_2.13/g-C₃N₄ heterojunction with enhanced photocatalytic activity

The extensive consumption of fossil fuels increases CO₂ concentration in the atmosphere, resulting in serious global warming problems. Meanwhile, the problem of water contamination by organic substances is another significant global challenge. We have successfully synthesized ZnGa_1.01Te_2.13/g-C₃N₄ (ZGT/GCN) composites for the first time as effective photocatalysts for both pollutant degradation and CO₂ reduction. ZGT/GCN composites were synthesized by a simple hydrothermal method. The prepared photocatalysts were characterized by XRD, SEM, TEM-EDS, DRS, BET, PL, and XPS. The ZGT/GCN heterojunction exhibited considerably enhanced photocatalytic activity in the degradation of crystal violet (CV) as well as in the photoreduction of CO₂ when compared to pure ZGT and GCN semiconductors. The optimal rate constant for CV degradation was obtained with the ZGT-80%GCN composite (0.0442 h^-1), which is higher than the constants obtained with individual ZGT and GCN by 7.75 and 1.63 times, respectively. Moreover, the CO₂ reduction yields into CH₄ by ZGT-80%GCN was 1.013 μmol/g in 72 h, which is 1.21 and 1.08 times larger than the yields obtained with ZGT and GCN. Scavenger and ESR tests were used to propose the photocatalytic mechanism of the ZGT/GCN composite as well as the active species in the CV degradation.