Synthesis And Photocatalytic Properties Of Visible-Light-Driven Bi₂₄Al₂O₃₉ Photocatalysts

The global environment pollutions have attracted tremendous attentions from many countries. The research of visible-light photocatalyst with high utilization efficiency of solar energy to degrade organic pollutant, has become a hot research covering materials science, chemistry and environmental science in recent years. Most studies have been paid to TiO2photocatalysts for their cheapness, non-toxicity, stability and so on. However, with the big energy gap (3.2eV), TiO2could not be activated under visible-light, which results in poor utilization of solar energy. For this reason, developing new photocatalysts capable of responding to visible light has become the urgent needs in the field of photocatalysis. Bismuth compounds have received more and more attention due to their high photocatlytic activity and narrow energy gap. Hence, the synthesis, morphology control, and photocatlytic properties of visible-light-driven were studied in this paper, and the research contents are as follows:In this study, the Bi24Al2O39photocatalyst powder was synthesized via simple sol-gel method and analyzed for the phase composition, crystal structure, morphology of the as-prepared samples and the optical absorption through the XRD, SEM, TEM, HRTEM and UV-vis DRS. For the acid red G solution (ARG) as the goal pollutant in the photocatalytic degradation, the preparation conditions, such as calcination temperature, were studied in this paper. Meanwhile, the degradation reaction conditions, such as catalyst dosing quantity and concentration of initial target pollutants, were also studied in this paper.To further investigate the effect of catalyst morphology to the photocatalytic activity, the mesoporous hollow sphere Bi24Al2O39photocatalyst was synthesized via a glucose polymerization-surface cation adsorption one-step method, and was analyzed for the phase composition, crystal structure, morphology of the catalyst via XRD, SEM, HRTEM, XPS, UV-vis DRS, FI-IR, TG-DSC and N2adsorption/desorption analysis. Meanwhile, a possible growth mechanism was also studied. The photocatalytic activity of the as-prepared mesoporous hollow sphere Bi24Al2O39photocatalyst was investigated with the acid red G solution (ARG) and gaseous formaldehyde as the water goal pollutant and gas goal pollutant in the photocatalytic degradation. The dynamics characteristics of the degradation were studied and it was confirmed that the degradation process of acid red G solution follows first order kinetics. Moreover, with the help of Terephthalic acid photoluminescence probing technique and collector of radical species, it was confirmed that the h+and O2·-are the major radical species in the photocatalytic degradation. Meanwhile, the reason of high photocatalyitic activity of mesoporous hollow sphere Bi24Al2O39photocatalyst was analysed in this paper.