氧化铝担载的贵金属铱基催化剂的制备及其对甲醇裂解反应的催化性能

Preparation of Alumina-Supported Nobel Metal Iridium Catalysts and Their Catalytic Performance for Methanol Decomposition

以ZrO2,La2O3或MgO为助剂制备了氧化铝担载型铱基催化剂,考察了其对甲醇裂解反应的催化性能,并用X射线光电子能谱、程序升温还原、H2程序升温脱附和CO程序升温脱附等技术对催化剂进行了表征.结果表明,ZrO2,La2O3和MgO助剂的引入均能提高主产物氢气和CO的选择性.ZrO2是甲醇裂解反应的优良助剂,可以显著提高甲醇的转化率和氢气的收率.氧化铝担载型贵金属铱基催化剂上存在强的氢溢流现象,这使催化剂具有良好的反应性能,同时有利于产物的脱附,氧化物助剂的加入能够进一步促进氢的溢流.

The alumina-supported noble metal iridium catalysts were prepared by the impregnation method. The effect of additive ZrO2, La2O3, or MgO on the catalytic performance was investigated. The supported catalysts were used for the methanol decomposition reaction and were characterized by X-ray photoelectron spectroscopy, temperature-programmed reduction （TPR）, temperature-programmed desorption of hydrogen （H2-TPD）, and temperature-programmed desorption of carbon monoxide. The promoter addition could remarkably improve the hydrogen selectivity and CO selectivity of Ir/Al2O3 catalyst in the methanol decomposition. La2O3 and ZrO2 were also good promoters for enhancing the methanol conversion. Both hydrogen and CO were held strongly by the MgO-modified Ir/Al2O3 catalyst, which was not favorable for the methanol conversion. The results of TPR and H2-TPD showed that hydrogen spillover existed in the alumina-supported iridium catalyst. The addition of one of the three promoters could significantly enhance the hydrogen spillover effect.