Preparation of Ordered Mesoporous Alumina Supported-ZnO/NiO Nanocomposite Using Supercritical Carbon Dioxide Impregnation and Its Photocatalytic Performance

Graphical ZnO/NiO nanoparticles supported on ordered mesoporous alumina (OMA) have been prepared via supercritical carbon dioxide impregnation and used as the photocatalyst for degradation of Congo Red under simulated sunlight irradiation. The ordered mesostructures of OMA were well-maintained during the preparation. The photocatalytic activity of the composite catalyst with uniform particle distribution and rich pore structure was superior to those of commercial P-25 and the composites prepared via incipient wetness impregnation. ZnO/NiO nanoparticles supported on ordered mesoporous alumina (OMA) have been prepared by supercritical carbon dioxide impregnation using Zn(NO 3 ) 2 ⋅ 6H 2 O and Ni(NO 3 ) 2 ⋅ 6H 2 O as the precursors, supercritical carbon dioxide as the solvent and methanol as the co-solvent. The ordered mesostructures of OMA were well-maintained during the preparation. Ordered mesoporous alumina was prepared via solvent evaporation self-assembly. The photocatalytic performance of ZnO/NiO/OMA composites for degradation of Congo Red was studied under simulated sunlight irradiation. The results showed that photocatalytic activity of the ZnO/NiO/OMA prepared by supercritical carbon dioxide impregnation was superior to those of commercial P-25 and the composites prepared via the incipient wetness impregnation. The removal rate of Congo Red was found to be dependent on both the microstructure of the prepared ZnO/NiO/OMA composites and also the molar ratio of ZnO/NiO nanoparticles in OMA. The optimal molar ratio of ZnO/NiO was investigated to achieve a maximum photocatalytic activity.