短孔道Cu-Mn/Zr-Ce-SBA-15催化剂的制备及其催化甲苯燃烧性能

摘要

采用水热法制备了Zr-Ce-SBA-15(ZCS)介孔材料,并以它为载体,通过浸渍法制备了不同Cu/Mn比和Cu-Mn含量的Cu-Mn/ZCS催化剂.采用N2吸附-脱附、透射电镜、扫描电镜、X射线衍射和X射线光电子能谱(XPS)等手段对催化剂进行了表征,并在微型固定床反应器上评价了催化剂催化甲苯燃烧性能.结果表明,Cu-Mn/ZCS催化剂具有六方板状形貌和高度有序的短孔道介孔结构(孔道长0.4～0.5 μm).20%Cu-Mn/ZCS催化剂的比表面积、孔体积和孔径分别为296m2/g,0.42cm3/g和6.4nm.与长孔道的20%Cu-Mn/SBA-15催化剂(孔道长 1～2μm)相比,20%Cu-Mn/ZCS催化剂上甲苯燃烧反应的T95(转化率达95%以上的反应温度)从284℃降至270℃,表明短孔道Cu-Mn/ZCS催化剂具有更高的催化活性.%The mesoporous Zr-Ce-SBA-15 (ZCS) material with short mesochannels was synthesized through a hydrothermal route. A series of Cu-Mn/ZCS catalyst samples with different Cu/Mn ratios and Cu-Mn contents were prepared by impregnation. The structure of the catalyst samples was characterized by N2 adsorption-desorption, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalytic performance of the catalyst for toluene combustion was evaluated in a fixed-bed microreactor. The results reveal that the Cu-Mn/ZCS catalyst has unique hexagonal platelet morphology and possesses highly ordered two-dimensional hexagonal mesoporous structure with short channels (0.4-0.5 μm). The specific surface area, pore volume, and pore diameter of the 20％Cu-Mn/ZCS are 296 m2/g, 0.42 cm3/g, and 6.4 nm, respectively. Compared with 20％Cu-Mn/SBA-15 with longer channel length (1-2 μm), the temperature of 95％ toluene conversion (T95) over 20％Cu-Mn/ZCS decreases from 284 to 270 ℃, indicating that the short channeled Cu-Mn/ZCS catalyst possesses higher catalytic activity than that over Cu-Mn/SBA-15.