MoVBiTeO/SiO_2对丙烷选择氧化制丙烯醛反应的催化性能

Catalytic Performance of MoVBiTeO/SiO_2 for Selective Oxidation of Propane to Acrolein

用浸渍法制备了一系列不同Mo/V比的MoVBiTeO/SiO2催化剂,并用X射线衍射、拉曼光谱、X射线光电子能谱、程序升温还原和红外光谱等方法对催化剂的结构、氧化还原性质和酸性进行了表征,考察了催化剂对丙烷选择氧化制丙烯醛反应的催化性能.结果表明,Mo与V组分之间存在较强的相互作用,调变了催化剂的结构,并形成了氧化还原循环(V5++Mo5+V4++Mo6+),促进了催化剂中电子和O物种的传递,使催化剂的低温可还原性增强,催化活性提高.Mo组分有利于形成L酸位,而V组分有利于形成B酸位.这可能是丙烯醛选择性随Mo/V比增大而逐渐提高的原因之一.当Mo/V摩尔比为6时,催化剂具有最高的丙烯醛收率(9.7%).

A series of MoVBiTeO/SiO2 catalyst samples with different Mo/V ratios were prepared by the impregnation method. The catalyst structure, reducibility, and acidity were characterized by XRD, Raman, XPS, TPR, and FT-IR techniques, and the catalytic performance of the catalyst for selective oxidation of propane to acrolein was evaluated. The results indicated that the interaction between Mo and V components modified the catalyst structure, and the redox cycle of V^5＋＋Mo^5＋←→V^4＋＋Mo^6＋ was formed. The improvement in the reducibility of the catalyst might be responsible for the increase in propane conversion. The V and Mo components were responsible for B acid and L acid, respectively. When the Mo/V ratio increased, the amount of B acid decreased, and the catalyst selectivity for acrolein increased. Among the investigated catalyst samples, the sample with a Mo/V molar ratio of 6 exhibited the best catalytic performance.