OMS-2制备方法对其负载Cu催化剂CO氧化性能的影响

采用3种不同方法制备氧化锰八面体分子筛(OMS-2),通过浸渍负载CuO制备了一系列CuO含量为10.0%(质量分数)的CuO/OMS-2催化剂,考察了催化剂在CO催化氧化反应中的催化性能,并利用X射线衍射(XRD)、N_2吸附(BET)、透射电镜(TEM)、X射线光电子能谱(XPS)、程序升温还原(H2-TPR)等手段对催化剂进行了表征.结果表明,固相法制备的S-OMS-2为纳米棒状形貌、结晶度低、比表面积大,而回流法和水热法的OMS-2为针状或纤维状形貌、结晶度高、比表面积小.OMS-2制备方法对其负载Cu催化剂上的CO氧化反应影响较大,CuO/S-OMS-2具有最高的催化活性,这可能是因为CuO/S-OMS-2中较大的比面积、较多的晶格缺陷以及高分散的CuO提供了更多有利于CO氧化反应的Cu-O-Mn界面.

Effect of OMS-2 support preparation technique on CO oxidation of Cu/OMS-2 catalysts

OMS-2 supports were synthesized by three different methods,and a series of CuO/OMS-2 catalysts with CuO loading of 10.0 t%(mass fraction)were synthesized by the impregnation method.The synthesized catalysts were characterized by X-ray diffraction,N_2 adsorption,transmission electron microscopy,X-ray photoelectron spectroscopy and H2-temperature programmed reduction and their catalytic activities for CO oxidation were evaluated on a continuous flow fixed-bed reactor.It was found that the S-OMS-2 synthesized by the solid phase method with nanorod morphology has a lower crystallinity but a larger specific surface area,whereas,the OMS-2 by the refluxing method or the hydrothermal method with needle-like or fibrous morphology shows a higher crystallinity but a lower specific surface area.The synthesized method for OMS-2 has a great effect on the catalytic activity of CuO/OMS-2.The CuO/S-OMS-2 catalyst exhibited the highest catalytic activity for CO oxidation.The superior catalytic activity observed on CuO/S-OMS-2 is probably associated to its larger surface area,more lattice defects as well as highly dispersed CuO species,which can provide more Cu-O-Mn interfaces for CO oxidation.