Study on modification of titanium-based metal-organic framework and catalytic performance
(2.School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, China 100190)
【Abstract】A series of materials were prepared by modifying titanium-based metal-organic framework material NH2-MIL-125 with hydrogen peroxide at a certain temperature. The effects of modification methods and conditions on the properties of materials were studied systematically. However, NH2-MIL-125 as a photocatalyst suffers from low catalytic activity and stability, which largely restrict its practical applications. In order to improve the catalytic activity of NH2-MIL-125, we adopted a solvothermal route by using H2O2 to modify NH2-MIL-125. A series of materials were synthesized by treating NH2-MIL-125 with different volumes of H2O2 at different temperatures. X-ray diffraction, scanning electron microscope, transmission electron microscope, ultraviolet-visible light absorption spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and N2 adsorption analysis were used to characterize the structures and properties of the obtained product. Furthermore, their photocatalytic performances for the visible-light-driven oxidation of benzyl alcohol were tested. The results show that the product modified by 10 mL H2O2 at 50 ℃ exhibits excellent catalytic activity and selectivity. The maximum turnover frequency is nearly 6 times as high as that of NH2-MIL-125 at the same experimental conditions. The partial loss of organic ligands and the introduction of peroxide groups could generate more catalytic-active sites, which is responsible for the improved catalytic activity.
【Keywords】 metal-organic framework; NH2-MIL-125; catalyst; photochemistry; oxidation;
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