1. Master Thesis

- Thesis topic: Application of CQDs/ZnO nanorods heterojunction for visible light-driven photocatalytic NO degradation

- Doi: https://doi.org/10.6840/cycu202201061

- Abstract: 

       Nitric oxide (NO) is regarded as the main component of air pollutant which has been causing environmental problems such as acid rain, photochemical smog and even human health. Among various techniques deployed to solve the problems, photocatalysis has attracted much attention due to its ability to degrade NO at low concentration combined with a cheap, sustainable and environmentally friendly process. Recent studies have proven that ZnO Nanorods (NRs) may be applied as potential photocatalyst due to their high transport charge efficiency, surface-to-volume ratio, and high performance. However, there is still less information regarding its optimum synthesize methods. In this study, high-performance ZnO NRs photocatalyst were successfully synthesized via one-step solvothermal. The effect of growth times and temperatures on the morphology and surface area of ZnO NRs are investigated through XRD, FTIR, SEM, TEM, BET, and DRS. The results show that the ZnO NRs synthesized at 100oC for 6 hours are the best samples with the highest photocatalytic removal efficiency of NO (78.8% under solar light and 62.2% under visible light). In addition, CQDs supported on the surface of ZnO NRs greatly improve the efficiency of light absorption and NO degradation by up to 11.5% and 7.7% respectively with solar and visible light irradiation. Furthermore, the mechanism of photocatalysis of NO degradation was also suggested through the active species trap experiment and ESR analysis. Finally, CQDs/ZnO NRs showed high stability under visible light irradiation, with only 7.7% reduction after 5 reuses.

Keywords: Nitric oxide, Photocatalysis, ZnO nanorods, CQDs/ZnO nanorods, solar light, visible light