钛基金属-有机框架材料的改性及其催化性能研究

Study on modification of titanium-based metal-organic framework and catalytic performance

使用双氧水在一定温度下对钛基金属-有机框架材料NH2-MIL-125进行改性处理,制备得到一系列材料,系统地研究了改性方法及改性条件对材料性能的影响。结果表明,经改性处理后的材料,在可见光催化苯甲醇氧化反应中的催化速率有显著提高;同时,改性过程中的双氧水用量及改性温度对材料的结构、性质和光催化性能都有十分重要的影响。当双氧水为10 ml、改性温度为50℃时,改性材料具有优异的催化活性、选择性以及良好的稳定性,其催化速率与NH2-MIL-125相比提高近6倍。

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,a solvothermal route by using H2O2 was used to modify NH2-MIL-125.A series of materials were synthesized by treating NH2-MIL-125 with different volumes of H2O2 at different temperatures.Xray 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.