铯添加对VO_x/SBA-15催化剂丙烷氧化脱氢性能影响

Effect of Cesium Loading on Catalytic Activity of VO_x/SBA-15 Catalysts for Propane Oxidative Dehydrogenation

我们考察了碱金属铯的添加对具有单一活性中心(分立的VO4四面体)的VOx/SBA-15催化剂上丙烷氧化脱氢反应性能的影响,发现铯的加入可以显著改善丙烯的选择性.在相同的丙烷转化率时,丙烯选择性提高了约10%.对催化剂的X射线衍射,拉曼光谱,程序升温还原,吡啶吸附IR光谱和程序升温脱附表征结果表明,少量碱金属的加入,并未改变活性中心的结构及其可还原性能,但明显降低了催化剂表面酸量,尤其是B酸量,从而有利于产物丙烯的脱附,抑制了深度氧化产物COx的产生,提高了丙烯的选择性.

The effect of cesium loading on the performance of single-site （ pseudotetrahedral monovanadate VO4 ） VOx/SBA-15 catalysts for propane oxidative dehydrogenation was investigated. The addition of Ce significantly improved the selectivity of propene which was enhanced by about 10% at the same propane conversions. The catalysts were characterized by XRD, Raman, H2-TPR, NH3-TPD and FT-IR spectroscopy of pyridine adsorption. The resuits indicated that the addition of a small amount of cesium did not change the structure and reducibility of active centers but resulted in a decrease of Broensted acid sites which favors propene desorption and prevents the overoxidation of propene to carbon oxides.