不同方法制备的钒基催化剂对异丁烷脱氢性质的影响

通过浸渍、 共沉淀、 浓缩结晶、 水热和水热 流体干燥法制备V-Al-O催化剂, 采用XRD,TPR,TPD和ESR等技术对催化剂的表面性质和结构进行表征. 结果表明, 制备方法影响催化剂表面钒物种的分散、 还原能力、 表面酸性和结构状态; 表面钒物种的分散度和活性位数量是影响异丁烷脱氢活性的主要因素; 催化剂表面Lewis酸量是影响异丁烯选择性的主要因素.

Activities of Vanadia-based Catalysts Prepared with Different Methods for Dehydrogenation of Isobutane to Isobutene

The V-Al-O catalysts prepared via impregnating, co-precipitation, hydrothermal, concentration, and hydrothermal fluid drying, were characterized via XRD, TPR, TPD and ESR, etc. At the same time, they were compared with V₂O₅/γ- Al₂O₃ catalyst prepared via impregnation in the structure and dehydrogenation activities for dehydrogenation of isobutane to isobutene. It was found that the activities of the catalysts were obviously dependent on the preparation methods. The catalyst with large surface, surface enriched and well dispersedvanadia showed a higher dehydrogenation activity. Furthermore, the amount of Lewis acid on the surface of the catalyst was also an important factor to affect the selectivity of catalyst for isobutene.