摘要
采用浸渍法制备了Pd-Ce/γ-Al_2O_3系列催化剂,研究了催化剂对低浓度甲烷催化燃烧反应活性的影响,采用扫描电镜(SEM)、氮气吸脱附曲线以及H_2程序升温还原(H2-TPR)技术对催化剂结构特征和化学性质进行表征和分析.针对焙烧温度、助剂添加量对催化活性的影响进行了研究,并对催化剂循环使用的催化活性进行了考察.结果表明:焙烧温度为550℃时催化效率最佳,相同催化温度下效率最高相差40%左右,双金属Pd-Ce催化剂较之单金属Pd催化剂有助于提高甲烷催化活性,但催化效果并不明显,经多次循环反应后可明显提高其催化活性,与首次实验相比,催化效率最高相差约50%左右,分析原因可能为催化剂经多次催化反应使催化活性组分Pd O与CeO_2之间的协同作用加强,提高PdO的分散度并降低催化剂表面吸附氧的脱附能,从而提高了催化剂的催化活性.
Bimetallic Pd-Ce/γ-Al2O3series catalysts were prepared by impregnation method in our experiment.Effects of the catalysts performance on the low concentration methane catalytic combustion were investigated.Structures and chemical properties of the catalysts were characterized and analyzed by scanning electron microscopy(SEM),N2adsorption/desorption isotherms and H2-temperature programmed reduction(H2-TPR).Effects of different calcinations temperature and additive dosage on catalytic activities were studied;the catalytic activity of the recycling catalysts was investigated at the same time.The results showed that the optimal calcination temperature was550℃,the highest efficiency difference of about40%at the same catalytic temperature.Compared with the single metal catalyst,bimetallic catalyst was benefit to improve the catalytic activity,but the catalytic effect was not obvious.However,the catalytic activity could be improved significantly when being used for many times,compared with the first experiment,the catalytic efficiency of the highest difference of about50%.The probably reason were that the synergistic effects between PdO and CeO2could be strengthen,the dispersion of the PdO could be improved,and the desorption energy of the adsorption oxygen could be reduced,all of which enhanced the catalyst activity.
作者
梁文俊
石秀娟
邓葳
李坚
何洪
LIANG Wen-jun;SHI Xiu-juan;DENG Wei;LI Jian;HE Hong(Key Laboratory of Beijing on Regional Air Pollution Control, Beijing University of Technology, Beijing 100124, China)
出处
《中国环境科学》
EI
CAS
CSSCI
CSCD
北大核心
2017年第7期2520-2526,共7页
China Environmental Science
基金
国家"863"计划资助项目(2011AA03A406)
北京市自然科学基金资助项目(8162009)
