浸渍溶剂对Pt-Sn/SBA-15催化剂丙烷脱氢性能的影响

以乙醇和水为溶剂配制相应活性组分盐溶液作为浸渍液,研究了不同条件下制备的Pt-Sn/SBA-15催化剂用于丙烷脱氢时的催化性能;采用XRD、BET、TEM和CO脉冲吸附等方法对载体和催化剂进行了表征。实验结果表明,浸渍溶剂对Pt-Sn/SBA-15催化剂性能的影响显著,以氯化亚锡水溶液浸渍Sn、以氯铂酸水溶液浸渍Pt的催化剂性能最好。Sn浸渍液的溶剂对催化剂结构影响不明显,而Pt浸渍液的溶剂不同时催化剂的Pt分散度有显著差异。在水溶液中,氯铂酸可电离成氢阳离子和氯铂酸根阴离子,离子在水中分散存在;而在乙醇溶液中,由于乙醇极性比水差,氯铂酸不电离形成离子,仍以分子形式存在并容易团聚,从而导致氯铂酸水溶液和乙醇溶液浸渍后的Pt-Sn/SBA-15催化剂的Pt分散度有较大差异。

Effect of Impregnation Solvent on Catalytic Performance of Pt-Sn/SBA-15 in Propane Dehydrogenation

The effects of the preparation conditions of Pt-Sn/SBA-15 catalysts on their catalytic performance in propane dehydrogenation were investigated.The catalysts were prepared by dissolving the salts of active ingredients in distilled water or ethanol and then impregnating the SBA-15 molecular sieve support with the salt solutions.The results showed that the solvents affected the catalyst performance notably.The supports and catalysts were characterized by means of XRD,BET and CO pulse adsorption.The results showed that the catalysts had different structure and specific activity.The catalyst prepared by the impregnation with aqueous solutions of tin dichloride and chloroplatinic acid has the best catalytic performance.In the aqueous solutions,chloroplatinic acid can ionize into hydrions and chloroplatinic acid radical anions,and in the ethanol solutions,chloroplatinic acid still exists in the form of molecular,which leads to the very different metal dispersity on the Pt-Sn/SBA-15 catalysts.