Pd催化剂表面物种对丙炔加氢性能的影响

Influence of surface species on Pd catalysts for propyne hydrogenation performance

采用H_(2)-TPR-MS-IR、CO脉冲吸附、He-TPD、H_(2)-TPR-MS、AFM-IR等方法研究了Pd催化剂的表面物种及Pd金属分散度,确定了Pd催化剂的表面物种状态,分析了Pd催化剂的表面物种与催化剂丙炔加氢性能的关系。实验结果表明,Pd催化剂表面存在碳物种和氮物种,碳物种和氮物种在800℃以上可被完全脱除。Pd催化剂表面存在的碳物种和氮物种更有利于Pd的分散,促使反应向预期的方向进行,阻碍丙烯的进一步加氢,从而有利于选择性丙炔加氢反应。

The surface species and metal dispersion of Pd catalysts were studied by H_(2)-TPR-MS-IR,CO pulse adsorption,He-TPD,H_(2)-TPR-MS,and AFM-IR.The surface species states of Pd catalyst were determined.The relationship between the surface species of Pd catalyst and the performance of propyne hydrogenation was also investigated.The results indicate that there are indeed carbon and nitrogen species on Pd catalyst surface,which could only be completely removed above 800℃.The presence of carbon and nitrogen species on the surface of Pd catalyst is benefit for Pd dispersion,promoting the reaction to the expected product direction,and preventing further hydrogenation of propylene.So they are benefit for selective propyne hydrogenation reactions.