PdCl_2-CuCl_2/Al_2O_3催化剂低温催化CO氧化的失活机理  

Deactivation mechanism of PdCl_2-CuCl_2/Al_2O_3 catalysts for CO oxidation at low temperatures

作　　者：封雅芬 王丽[1] 张艳慧[1] 郭耘[1] 郭杨龙[1] 卢冠忠[1] 

机构地区：[1]华东理工大学工业催化研究所,上海200237

出　　处：《催化学报》2013年第5期923-931,共9页

基　　金：国家重大科学研究计划(2013CB933201);国家重点基础研究发展计划(973计划;2010CB732300);新世纪优秀人才计划(NCET-10-0377);中央高校基本科研业务费(222201013003)~~

摘　　要：采用X射线衍射、N2吸-脱附、X射线光电子能谱分析、氢气-程序升温还原和原位红外漫反射等方法对新鲜和失活的PdCl2-CuCl2/Al2O3低温催化CO氧化催化剂进行表征,研究了高相对湿度(100%)下催化剂的失活机理.结果表明,催化剂表面沉积的水使得活性铜物种容易从催化剂表面向载体孔道内部迁移,由于Pd、Cu相互作用弱化从而减弱了Pd与Cu物种间的相互作用,使得催化剂的氧化还原性能受到影响,抑制了Pd0再氧化为Pd2+的过程,从而因CO氧化反应中催化剂氧化还原循环受阻而导致失活.Supported Wacker catalysts exhibited high activity for low temperature CO oxidation, but high con-centrations of water in the reaction gas could lead to the deactivation of the catalyst. The PdCl2-CuCl2 /Al2O3 catalysts were prepared, and a high relative humidity deactivation mechanism was suggested after characterizing the fresh and spent catalyst by X-ray diffraction, N2 absorp-tion-desorption, X-ray photoelectron spectroscopy, H2 -temperature programmed reduction and in situ diffuse reflectance infrared Fourier transform spectroscopy. The results showed that the water could adsorb and condense on the surface of the catalyst, which arouses the aggregation and trans-fer of Cu species into the internal pores of the catalyst. This weakens the interactions between the Pd and Cu species and reduces the re-oxidation ability of Pd0 to Pd2+, which blocks redox cycling and results in the decrease of CO oxidation activity.

关 键 词：低温一氧化碳氧化 氯化钯 氯化铜 三氧化二铝 失活 

分 类 号：O643.32[理学—物理化学]