Study On The Synthesis And Photocatalytic Property Of CuCr_xAl_1-xO₂-W_1-yMo_yO₃ For Water Decomposition

Photocatalytic water splitting as an environmental-friendly green process has been considered as one of the most ideal pathways to produce hydrogen. Amongest all the catalysts for photocatalytic water splitting, solid solution due to modulated properities of the band structure has a great significance for the preparation of suitable p-n compound catalyst for photocatalytic water splitting.W_1-y Mo_y O₃（0-0.2） were prepared by coprecipitation method and solid method,respectively, and were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, ultraviolet-visible diffuse reflectance（UV-vis DR）. The results showed that W_1-y Mo_y O₃ solid solution were synthesized successfully, and with the increase of Mo species in the solid solution, the absorption edge of W_1-y Mo_y O₃ gradually shifted to visible light and forbidden gap decreased effectively. Cu Cr O₂-W_1-y Mo_y O₃ and Ru/(Cu Cr O₂-W_1-y Mo_y O₃) were obtained by mechanical grinding and heat-treatment, and their hydrogen evolution under irradiation of xenon lamp and mercury lamp were also evaluated. Results showed that Cu Cr O₂-W_1-y Mo_y O₃ and Ru/(Cu Cr O₂-W_1-y Mo_y O₃) had good photocatalytic activity, but the stability had not good enough.Further, in order to examine the stability of W_1-y Mo_y O₃, W_1-y Mo_y O₃（0-0.02） were prepared by solid method. Cu Cr O₂-W_1-y Mo_y O₃ with a ratio of23yy-1Cu Cr OOMo W: nn =0.8:1 were synthesized by mechanical grinding and heat-treatment. The results of water splitting indicated that Cu Cr O₂-W0.99Mo0.01O₃ exhibited higher photocatalytic activity,corresponding H2 production up to 184.8 μmol·h-1. With 0.5 wt% Ru loading, H2 production over the Ru/（Cu Cr O₂-W0.995Mo0.005O₃） was up to 306.1 μmol·h-1 under the irradiation of 250 W mercury lamp, and the H2 production over the catalyst were 104.7μmol and 6.6 μmol respectively, from feeds of glycerin water solution with 0.03 mol·L-1and pure water solution under the 3 h irradiation of 300 W xenon lamp. Then, roasting atmosphere were systematically studied on the property of W_1-y Mo_y O₃. Large amounts of data verified that Cu Cr O₂-W_1-y Mo_y O₃ had higher photocatalytic activity under air, but property of W_1-y Mo_y O₃ was more stable under N2.A series of Cu Cr_x Al_1-x O₂ solid solution were prepared by semi-wet method, and the samples were characterized by XRD、UV-vis DR、SEM、TEM. Results showed that withthe increase of Cr in the Cu Cr_x Al_1-x O₂, the Cu Cr_x Al_1-x O₂ diffraction patterns peak of asobtained products appeared regularly migration, which verified that Cu Cr_x Al_1-x O₂ solid solution were prepared successfully. Meanwhile the absorption edge of Cu Cr_x Al_1-x O₂ gradually shifted to visible light and forbidden gap decreased effectively. Ru loading also enhanced the photocatalytic activity. 0.5 wt%Ru/（Cu Cr0.9Al0.1O₂-WO₃） can produce H2 up to 186.5 μmol·h-1 under mercury lamp and the catalyst can produce H2 up to 53.5 μmol·h-1after glycerin added into the water solution, and split pure water 14.5 μmol for 3 h under the irradiation of 300 W xenon lamp.