MnO_x对Pt/CeZrO_2催化剂在水汽和CO_2环境下CO氧化的影响  

Effect of MnO_x on Pt/CeZrO_2 catalyzed CO oxidation under water vapor and CO_2 conditions

作　　者：朱丽 邓芸 宋宇鹏[2] 王月娟[1] 鲁继青[1] 罗孟飞[1] ZHU Li;DENG Yun;SONG Yupeng;WANG Yuejuan;LU Jiqing;LUO Mengfei(Institute of Physical Chemistry,Zhejiang Normal University,Jinhua 321004,Zhejiang,China;School of Chemical and Pharmaceutical Engineering,Jinhua Polytechnic,Jinhua 321017,Zhejiang,China)

机构地区：[1]浙江师范大学物理化学研究所,浙江金华321004 [2]金华职业技术学院化工与制药学院,浙江金华321017

出　　处：《化工学报》2018年第4期1484-1492,共9页CIESC Journal

基　　金：浙江省公益技术应用研究项目(2016C31SA700016)~~

摘　　要：以CeZrO_2固溶体为载体,发现MnO_x的添加能促进Pt/CeZrO_2催化剂的CO氧化性能,并研究了MnO_x含量对催化剂CO氧化活性及抗H_2O和CO_2性能的影响。结果表明,随着MnO_x含量增加,催化剂活性呈现先升高后降低的趋势,在MnO_x含量为0.5%(质量分数)时活性最佳。MnO_x的添加降低了Pt颗粒尺寸并影响催化剂还原性能从而促进反应活性。水汽和CO_2对Pt/CeZrO_2催化剂的CO氧化活性有抑制作用,而MnO_x的加入能显著提高催化剂的抗水汽和CO_2的能力。反应动力学结果表明,在Pt/CeZrO_2催化剂上,反应气中引入H_2O和CO_2后,CO的反应级数有明显升高,说明H_2O和CO_2在催化剂表面与CO竞争吸附,导致CO反应活性下降;而在Pt/MnO_x/CeZrO_2催化剂上,CO的反应级数略有升高,说明MnO_x的添加能有效抑制H_2O和CO_2与CO的竞争吸附,从而改善了催化剂的抗H_2O和CO_2性能。Adding MnOx to CeZrO2 solid solution carrier could effectively enhance Pt/CeZrO2 catalyst activity for CO oxidation.The effect of the amount of MnOx on catalytic activity and resistance of H2O and CO2 was studied.The results showed that the activity of Pt/MnOx/CeZrO2 catalyst was first increased and then decreased as MnOx content was increased with a maximum activity at 0.5%(mass)MnOx content.The addition of MnOx improved catalyst activity by reducing Pt particle size and changing catalyst reducibility.The presence of H2O vapor and CO2 in feed gas suppressed activity of Pt/CeZrO2 catalyst,which was effectively alleviated by MnOx in the catalyst.Kinetic study revealed that CO reaction order was considerably increased with presence of H2O and CO2 for the Pt/CeZrO2 catalyst.Such a decline of catalyst activity might be due to competitive adsorption of H2O and CO2 over CO on catalyst surface.In contrast,the CO reaction order was slightly increased with presence of H2O and CO2 for Pt/0.5MnOx/CeZrO2 catalyst,implying that addition of MnOx could suppress competitive adsorption of H2O and CO2 over CO on catalyst surface and hence improve resistance to H2O and CO2.

关 键 词：PT催化剂 CO氧化 MNOX 动力学 

分 类 号：O643.3[理学—物理化学]