助剂Mg对Cu-Mn-Ce催化燃烧低浓度苯特性的影响

The Effects of Promoter Mg on Cu-Mn-Ce Catalytic Combustion for Low Concentration Benzene

VOCs的排放给人类健康和环境的危害日趋严重,本文采用浸渍法分别制备了不同Mg含量以及不同焙烧温度下的Cu-Mn-Ce/γ-Al_2O_3催化剂,以低浓度VOCs中的苯为催化对象,利用SEM、XRD以及TPR等表征手段和理论分析对催化剂的催化燃烧特性进行了研究。研究表明:一定量Mg的掺杂使得催化剂比表面积增加了2.1m^2·g^(-1),有效地提高催化剂的活性;在反应温度为200℃时,Cu_1Mn_(1.5)Ce_(0.5)Mg_(0.1)催化剂对苯的转化率比Cu_1Mn_(1.5)Ce_(0.5)催化剂提高了约7%左右,有效地提高了200～300℃范围内的转化效率,降低催化剂的活化能;另外,对催化剂长时间的催化研究中表明,Mg离子的添加有效地减少了催化剂表面的烧结,Mg离子在催化剂表面主要以MgO形式存在,MgO可以提高催化剂的热稳定性。

The harm of VOCs emission to human health and environment is becoming more and more serious. In this study, the Cu-Mn-Ce/γ-Al2 O3 catalyst with different Mg content and different calcination temperature was prepared by impregnation method. The catalytic combustion characteristics of the catalyst were analyzed by means of SEM, XRD, TPR and theoretical analysis. The study shows that a certain amount of Mg doping can increase the specific surface area of the catalyst by 2.1 m2·g-1 and improve the activity of the catalyst effectively. When the reaction temperature is 200℃, the conversion efficiency of Cu1 Mn1.5Ce0.5Mg0.1 catalyst to benzene is about 7%, and its activation is higher than that of the Cu1 Mn1.5Ce0.5. From 200℃ to 300℃, the conversion efficiency is effectively raised and the activation energy of the catalyst is reduced;in addition, the catalytic activity of the catalyst is reduced. In the long time catalytic study, it shown that the addition of Mg ions reduces the sintering of the catalyst surface effectively. The Mg ion exists on the surface of the catalysts mainly in the form of MgO, and which can improve the thermal stability of the catalyst.