Synthesis and photocatalytic decomposition of water under visible light irradiation of La₂Ti_2-xCo_xO₇ with pyrochlore structure

Photocatalysts La₂Ti_2-xCo_xO₇(x=0, 0.05, 0.10, 0.20) with pyrochlore structure were synthesized by sol-gel method. XRD, FT-IR, BET, and UV-Vis diffuse reflectance spectroscopy were used to characterize the crystal structure, specific surface area, and diffuse reflectance spectra, respectively, the formation rate of hydrogen was measured by the photocatalytic activity measurement device and gas chromatography (GC). The results indicated that the absorption pattern of La₂Ti_2-xCo_xO₇ was only generated in the ultraviolet region but a₂Ti₂O₇ with Co doping at B site had strong photoabsorption in the visible light region. The evolution rate of H2 in photolysis of H₂O by the La₂Ti₂O₇ photocatalysts which doped with Co at B site was highter than that of undoped La₂Ti_2-xO_xO₇. La2Ti1.9Co0.1O7 showed the best photocatalyst property in all photocatalysts of La₂Ti₂-_xCo_xO₇ (x=0-0.20).