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Titanate nanotubes were synthesized by a solvothermal process at a low temperature in a highly alkaline water-methanol mixed solution. Powders were characterized by XRD, TEM, BET and UV-vis absorption spectroscopy. The as-prepared samples was tested by the adsorptive process and photodegradation reaction of methylene blue (MB) dye under visible-light irradiation. The results indicated that the titanate samples are synthesized in the methanol-water volume ratios of 10:90, 20:80 and 30:70 are still highly absorbability and all the titanate samples as-prepared have higher photocatalytic activities compared with TiO2P25 in the degradation of MB under visible light irradiation.

This study successfully synthesized manganese-doped calcium zirconate phosphor and manganese-doped strontium zirconate phosphor using the sol-gel method. We employed X-ray powder diffraction and fluorescence spectroscopy to analyze the crystal structure and spectral characteristics of both phosphors. In X-ray powder diffraction analysis, data related to manganese-doped calcium zirconate phosphor and manganese-doped strontium zirconate phosphor were compared using X-ray diffraction comparison software to confirm the crystal structures of both phosphors. The crystal structure of manganese-doped calcium zirconate phosphor was in accordance with orthorhombic perovskites belonging to the Pnma {62} space group. The lattice parameters were a=5.762 Å, b=8.017 Å, and c=5.591 Å; c/a=0.97; volume=258.3 Å3, and density=4.611 g/cm3. The crystal structure of manganese-doped strontium zirconate phosphor conformed to orthorhombic perovskites belonging to the Pnma {62} space group, and the lattice parameters were a=5.818 Å, b=8.204 Å, c=5.797 Å; c/a=0.996; volume=276.7 Å3, and density=5.446 g/cm3. Fluorescence spectroscopy indicated that the primary broadband peak of manganese-doped calcium zirconate phosphor was located at 396.6 nm in the excitation spectrum corresponding to the 4T2(4G)4T1(4P) energy level transition. In the emission spectrum, the primary broadband peak was located at 596.6 nm, corresponding to the 4T2(4D)4T2(4G) energy level transition. For manganese-doped strontium zirconate phosphor, the primary broadband peak was located at 496.6 nm in the excitation spectrum and at 696.6 nm in the emission spectrum, corresponding to the 4T1(4G)4T2(4D) and 4E(4G)4T1(4G) energy level transitions, respectively.