摘要
利用浸渍法制备不同载体的钒基催化剂(V/β,V/γ-Al_2O_3),并考察该催化剂在丙烷氧化脱氢制丙烯反应中的活性.利用X射线衍射(XRD)、紫外-可见漫反射(UV-Vis DRS)、N_2吸附-脱附(BET)和原位红外光谱对催化剂进行表征.结果表明,β分子筛和γ-Al_2O_3具有大的比表面积,孔径分布窄,使V能够以高分散、孤立态的V物种存在.原位红外光谱结果表明,丙烯在8V/β-分子筛(8V/γ-Al_2O_3)和8V4Mg/β-分子筛(8V4Mg/γ-Al_2O_3)催化剂上吸附后,C—H键上的H与催化剂活性中心的晶格氧发生了作用形成H—O键,随着温度升高出现C—O键,C—O键将进一步氧化生成COx,且8V4Mg/β-分子筛(8V4Mg/γ-Al_2O_3)催化剂上出现C—O键的温度比8V/β-分子筛(8V/γ-Al_2O_3)催化剂上高,说明Mg有利于丙烯的选择性.500℃反应时,8V4Mg/β分子筛具有很好的催化活性,丙烯的选择性达71.9%,丙烷的转化率达16.7%.
A series of supported vanadia catalysts with different supports （V/β, V/γ-Al2O3 ） were prepared by the impregnation method. Their performance in the oxydehydrogenation of propane to propene （ODP） was studied. The catalysts were characterized by X-ray powder diffraction （XRD） , UV-Vis diffuse reflectance spectroscopy （UV-Vis）, N, adsorption-desorption （BET）and in suit in- frared spectroscopy （IR）. The result showed that the large specific surface area and the narrow pore size distribution of β zeolite and alumina led to a high dispersion of vanadium species on the supports and the vanadium species existing in isolated form. In suit IR showed that upon adsorptionon 8V/β and 8V4Mg/β, the hydrogen atoms of propene interact with the lattice oxygen of the catalytic active centers, forming H--O bonds. With the increase of temperature, species with C--O bond appear, which can be further oxidized to COx. On 8V4Mg/β（8V4Mg/γ-Al2O3） , the temperature when the species with C--O bond appear is higher than that on 8V/β （8V/γ-Al2O3） , indicating that addition of magnesium can inhibit deep oxidation of propylene. On 8VdMg/β the conversion of propane- reaches 16.7% with selectivity to propene of 71.9% at 500 ℃.
出处
《北京服装学院学报（自然科学版）》
CAS
北大核心
2016年第4期77-84,共8页
Journal of Beijing Institute of Fashion Technology：Natural Science Edition
基金
北京服装学院2016年研究生科研创新项目(120301990122)
