Fabrication of Three-Dimensional Ordered Mesoporous Manganese Oxides Used as High-Efficient Catalysts for Removal of Toluene and Carbon Monoxide

摘要

Using vacuum impregnation technology under the assistance of ultrasonic waves, three-dimensional (3D) ordered mesoporous, wormhole-like mesoporous structural MnO2 was synthesized from a metal source of manganous nitrate by using a three-dimensional ordered mesoporous molecular sieve KIT-6 as the template agent while using ethanol as a solvent. The physical properties of the material are characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), N-2 Adsorption-Desorption, and Fourier transform-infrared spectroscopy (FT-IR). Its catalytic performance was evaluated by the method of hydrogen temperature-programmed reduction (H-2-TPR) and the exhaustive oxidation of toluene and CO. It has been determined from the study that the prepared three-dimensional ordered mesoporous MnO2 has a tetragonal structure and a specific surface area of 194 m(2)/g; at the conversion rates of 50%, 90% and 100%, toluene has an ignition temperatures of 203 degrees C, 215 degrees C and 225 degrees C, respectively, and CO has an ignition temperatures of 114 degrees C, 158 degrees C and 180 degrees C, respectively. The excellent catalytic performance of 3D-MnO2 has a close relationship to its large specific surface area, good reducibility at low temperature, and high-quality three-dimensional ordered mesoporous structure.