g-C3N4 nanosheets decorated with carbon dots and CdS nanoparticles: Novel nanocomposites with excellent nitrogen photofixation ability under simulated solar irradiation

Abstract Photocatalytic nitrogen fixation, as one of the best alternatives to Haber-Bosch process, is a low–cost, eco-friendly, and mild technology that needs more efforts to find efficient photocatalysts with high stability. In this research, novel graphitic carbon nitride nanosheets/carbon dots/CdS (denoted as CN-NS/CDs/CdS) nanocomposites by prominent nitrogen photofixation capability under simulated solar irradiation were fabricated with decoration of CDs and CdS nanoparticles over CN-NS thorough a microwave-assisted method. The prepared ternary photocatalysts were investigated by XRD, EDX, SEM, TEM, HRTEM, UV–vis DRS, PL, FT-IR, TGA, BET, and EIS analyses. The results showed that photocatalytic activity of the CN-NS/CDs/CdS (30%) nanocomposite was 17.1, 5.64, 5.38, and 4.51-folds greater than those of the bulk CN, CN-NS, pure CdS, and CN-NS/CDs samples, respectively. Moreover, an insignificant loss in the activity of photocatalyst after several cycles displayed its high stability, which is vital for the sustainable photocatalytic procedures. The effects of CdS loading, pH of solution, electron scavenger, and solvent on the ammonia generation rate were also investigated and discussed. Eventually, a probable mechanism for the significantly enhancement of N2 photofixation performance was proposed.