摘要
挥发性有机物(VOCs)大量排放已成为日益严重的环境问题,为了实现VOCs的高效去除,本文采用自蔓延燃烧合成法制备了一系列锰铈复合氧化物催化剂,将稳恒直流电场引入典型VOCs气体苯的催化氧化过程,并基于不同电场条件下催化剂的理化性质表征结果进行机理分析.实验结果表明,Mnx Cey催化剂对含苯废气的去除有良好的效果,稳恒直流电场显著促进了催化剂的活性,其中Mn1 Ce3的催化性能最佳,电流为5 mA时,Mn1Ce3催化剂在155℃可达到50%的苯转化率,在202.4℃可达到90%的苯转化率,对应的转化温度T50和T90比传统方法分别降低了62.4℃和48.3℃,且电场中的反应活化能由52.32 kJ·mol^-1降低至32.31 kJ·mol^-1.根据实验现象及表征结果,发现协同效应与活性位点的快速持续再生及活性氧物种的转化有关,由此提出苯在Mnx Cey催化剂上的氧化机理及电场协同催化的反应模型.
Volatile organic compounds(VOCs)emissions have become a serious environmental problem.To achieve efficient VOCs removal,a series of manganese-cerium composite catalysts were prepared using self-propagating combustion synthesis in this study.Also,steady DC electric field was employed in the catalytic oxidation of benzene,a typical VOC gas,and the mechanism was analyzed based on the catalyst properties characterization under different electric field conditions.The results showed that Mnx Cey catalysts are effective for the removal of benzene-containing waste gases,and the electric field significantly promotes the activity of catalysts.Among the tested catalysts,Mn1 Ce3 shows the best performance.In the steady DC electric field with a current of 5 mA,benzene can be converted by 60% at 155℃,and by 90% at 202.4℃,with the corresponding conversion temperatures T50 and T90 reduced by 62.4℃ and 48.3℃,respectively.Moreover,the activation energy was reduced from 52.32 kJ·mol^-1 to 32.31 kJ·mol^-1.This synergistic effect can be attributed to the continuous formation of active sites and the conversion between oxygen species.Finally,the benzene oxidation mechanism over the Mnx Cey catalysts and a synergistic reaction model in the DC electric field are proposed.
作者
许得隽
闫瑞宁
李珂
李晓波
沈飞翔
林赫
黄震
XU Dejun;YAN Ruining;LI Ke;LI Xiaobo;SHEN Feixiang;LIN He;HUANG Zhen(Key Laboratory for Power Machinery and Engineering of Ministry of Education,Shanghai Jiao Tong University,Shanghai 200240;Shanghai Marine Diesel Engine Research Institute,Shanghai 201108)
出处
《环境科学学报》
CAS
CSCD
北大核心
2020年第3期827-837,共11页
Acta Scientiae Circumstantiae
基金
国家自然科学基金项目(No.51676127)
关键词
电场
苯
催化氧化
氧空位
锰铈催化剂
electric field
benzene
catalytic oxidation
oxygen vacancy
Mn/Ce catalyst
