Preparation Of CNT-TiO₂Nanohybrids And Their Emulsion Catalytic Abilities For Selective Oxidation Of Benzyl Alcohol

CNT-TiO2nanohybrids were successfully synthesized by CVD and hydrothermal methods. The as-made CNT-TiO2nanohybrids were characterized by FT-IR, SEM, XRD and nitrogen adsorption desorption technique, and their stabilized emulsion abilities were investigated by Optical Microscope technique. A probe reaction of the selective oxidations of benzyl alcohol to benzylaldehyde was used to evaluate and measure the catalytic abilities of Ru/CNT-TiO2.The potential of the as-made CNT-TiO2nanohybrids as solid emulsion catalyst supports is explored, of which the emulsion capacities and properties stabilized by the CNT-TiO2nanohybrids are correlated with their catalytic activities and selectivities.As emulsion supports, CNTs and TiO2could stabilize water in oil and oil in water emulsion systems respectively. The volume fraction of the emulsion stabilized by TiO2nanoparticles is larger than the one stabilized by CNTs. The droplets of emulsion stabilized by TiO2are relatively more uniform than that of the CNT-stabilized emulsion droplets. As the rutile content in TiO2increased from anatase to rutile, the activity of Ru/TiO2catalysts increased due to the strengthened emulsion capacities. In comparison to the Ru/TiO2catalysts, Ru/CNTs catalysts show better catalytic activities, demonstrating that the w/o emulsion speed up the oxidation of benzyl alcohol to benzylaldehyde.CNTs-TiO2composites were successfully synthesized using ethylene as carbon source and Ni/TiO2as catalyst by a chemical vapor deposition method. When the CNT content is in a range of40%to68%, o/w type reversal to w/o type emulsion takes place. In comparison to Ru/TiO2and Ru/CNTs catalysts, Ru/CNT-TiO2catalysts show better catalytic activities, demonstrating that the CNT-TiO2nanohybrids are effective catalyst supports for the benzyl alcohol oxidation in emulsion system.CNT-TiO2composites were successfully synthesized using isopropyl titanate as titanium source by a facile hydrothermal method. The emulsion capacities stabilized by the CNT-TiO2nanohybrid made by hydrothermal method is better than the CNT-TiO2nanohybrid made by CVD method, and resulte in the higher activity of Ru/CNT-TiO2.