Abstract:

The glass spheres are chemically etched to produce nano-pores on the surface， on which amorphous organotitanium polymer is prepared by the solvothermal method. The structures and optoelectronic properties of the materials are characterized by scanning electron microscopy （SEM）， X-ray diffraction （XRD）， inductively coupled plasma atomic emission spectroscopy （ICP-AES）， ultraviolet-visible diffuse reflectance spectroscopy （UV-Vis）， fluorescence spectroscopy （PL）， organic element analysis （OEA）， ultraviolet photoelectron spectroscopy （UPS）， fourier transform infrared spectroscopy （FT-IR） and so on. The supported amorphous organotitanium polymer exhibits an obvious absorption of visible light， and the fluorescence intensity is much lower than that of NH₂-MIL-125（Ti）， indicating more stable photogenerated electrons. In the photocatalysis of CO₂ with a 300 W xenon lamp as light source， the methanol yield reaches 941.6 μmol over the supported organotitanium polymer within 4 h of illumination， and the corresponding turnover frequency （TOF） is 46.4 h^－1. For comparison， NH₂-MIL-125（Ti）， consisting of the same organic ligands and metal ions， is prepared for the photocatalysis of CO₂. A TOF of only 0.28 h^－1 is obtained under the same performance conditions. Under the same conditions， the TOF of P25_{is 0.019 h^－1. Upon heat treatment， it shows that the glass spheres as the carrier have an obvious protective effect on the chemical stability of the organotitanium polymer. After treatment at 300 ℃， the supported organotitanium polymer exhibits a relatively stable photocatalytic performance. Comparatively， the methanol yield over the heat treated NH2-MIL-125（Ti） is decreased by 54%， as the result of the destruction of chemical structure and crystal structure.}

Key words: Glass spheres, Supported, Amorphous organotitanium polymer, Photocatalysis, Reduction of carbon dioxide