不同晶型二氧化锰纳米棒催化氧化氯苯性能的研究  

Catalytic Oxidation of Chlorobenzene over MnO_2 Nanorods with Different Phase Structures

作　　者：李经纬[1] 宋灿[1] 刘善堂[1] 

机构地区：[1]武汉工程大学化工制药学院、绿色化工过程教育部重点实验室,武汉430074

出　　处：《化学学报》2012年第22期2347-2352,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20873097;21071113);湖北省自然科学基金(No.2011CDA049);武汉市学科带头人(No.200951830551);湖北省教育厅科学技术研究重大项目(No.Z20091502)资助~~

摘　　要：采用水热法分别合成了α-,β-,γ-MnO2纳米棒,使用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、氢气程序升温还原(H2-TPR)和X射线光电子能谱(XPS)等技术对三种晶型MnO2纳米棒的结构和形貌进行了表征,并以氯苯(CB)为探针考察了其催化活性和稳定性.结果表明,三种晶型MnO2纳米棒在低温范围内均有较高的催化活性,且活性顺序为α-MnO2>γ-MnO2>β-MnO2.此外,还发现三种晶型MnO2纳米棒比无定形MnO2有更强的抗氯中毒能力.在三种晶型MnO2纳米棒中,α-MnO2纳米棒催化氧化氯苯的活性最佳,主要是由于该种MnO2纳米棒含有丰富的晶格氧并且具有较强的可还原能力.Mn-containing catalysts are widely used owing to their excellent redox properties,while in most cases they would deactivate to some extent in the oxidation process of the chloride volatile organic compounds（CVOCs） due to chlorine poisoning.In this work α-,β-,γ-MnO2 nanorods were synthesized via a hydrothermal route,and their catalytic performance for chlorobenzene（CB,as a model of CVOCs） and resistance to chlorine poisoning were studied.The results showed that the MnO2 nanorods with different phase structures exhibited high activities for low temperature catalytic oxidation of CB,and the catalytic activities of the MnO2 nanorods depended on the crystal phase of MnO2,following in the order of α-MnO2 γ-MnO2β-MnO2.Moreover,the MnO2nanorods showed high resistance to chlorine poisoning compared to the amorphous MnO2.The experiment results indicated that the conversion of CB over α-,β-,γ-MnO2nanorods at 250 ℃ remained stable at about 98%,82% and 90% respectively for 35 h.Contrasted to MnO2nanorods,the conversion of CB over amorphous MnO2 dropped from 80% to 32% in the same condition.Additionally,the as-synthesized MnO2 nanorods were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,H2 temperature-programmed reduction（H2-TPR） and X-ray photoelectron spectroscopy（XPS）.XRD results showed that the crystallinity of α-,β-,γ-MnO2 nanorods were different,and decreased in the order： βαγ,implying that the crystallinity of α-,β-,γ-MnO2 nanorods had no significant effect on its catalytic performance.SEM and TEM showed that three kinds of nanorods were well dispersed,and exhibited one-dimensional nanorods.H2-TPR and XPS results demonstrated that the high catalytic activity of α-MnO2 nanorods resulted from their rich lattice oxygen and good reducibility.Therefore,the enrichment of the lattice oxygen with excellent reducibility was considered as main reason of high activity of α-MnO2 nanorods for low temperature catalytic

关 键 词：α- β- γ-MnO2 纳米棒 晶型 氯苯 催化燃烧 

分 类 号：X51[环境科学与工程—环境工程] O643.32[理学—物理化学]