가시광하에서 페롭스카이트 촉매를 이용한 Methyl orange의 광분해 반응

Abstract

Photocatalytic decomposition of methyl orange over various catalysts has been investigated. The catalysts have been prepared by malic acid method and microwave irradiation method. These catalysts were characterized by XRD, BET, TG/DTA, TEM, DRS and XPS in order to determine the properties of various catalysts. In addition, their catalytic activity on photocatalytic decomposition reaction in the presence of oxygen was also examined in terms of different catalyst composition and synthesis method and the following conclusions are drawn.

In this study, we have investigated the photocatalytic activity for the decomposition of methyl orange on the LaCoO3 perovskite-type oxides prepared at different conditions using malic acid method. From the results of UV–Vis DRS, it was found that all the catalysts have the similar absorption spectrum up to visible region. The LaCoO3 catalyst prepared with 1.5mol of malic acid shows higher activity than LaFeO3 and LaMnO3. The extent of photo absorption in the visible region is correlated with the photocatalytic activity. In addition, the chemisorbed oxygen plays an important role on the photocatalytic decomposition of methyl orange and the higher the contents of chemisorbed oxygen, the better the performance of photocatalyst.

We have investigated the photocatalytic activity for the decomposition of methyl orange on the LaCoO3 perovskite-type oxides prepared at different conditions using microwave process. In the case of LaCoO3 catalysts calcined above 500℃, the formation of the perovskite crystalline phase was confirmed. From the results of UV–Vis DRS, it was revealed that all the catalysts have the similar absorption spectrum up to visible region. The chemisorbed oxygen plays an important role on the photocatalytic decomposition of methyl orange and the higher the contents of chemisorbed oxygen, the better the performance of photocatalyst.

Nanosized lead-substituted perovskite type oxides, La1-xPbxCoO3, were successfully synthesized using microwave-assisted method and characterized by TG/DTA, XRD, XPS, TEM and DRS. We have also investigated the photocatalytic activity for the decomposition of methyl orange on these oxides. From the results of UV–Vis DRS, it was found that all the catalysts have the similar absorption spectrum up to visible region and the absorption band moves to the higher wavelength on the lead-substituted LaCoO3 perovskite oxides compared to the lead-free LaCoO3 oxide. From XPS results, it was found that chemisorbed oxygen plays an important role on the photocatalytic decomposition of methyl orange and the higher the contents of chemisorbed oxygen, the better performance of photocatalyst.