不同晶相结构二氧化锰催化完全氧化乙醇  

Complete Catalytic Oxidation of Ethanol over MnO_2 with Different Crystal Phase Structures

作　　者：张洁[1] 张江浩 张长斌[1] 贺泓[1] 

机构地区：[1]中国科学院生态环境研究中心大气污染控制中心,环境模拟与污染控制国家联合重点实验室,北京100085

出　　处：《物理化学学报》2015年第2期353-359,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21422706);国家高技术研究发展计划项目(863)(2012AA062702)资助~~

摘　　要：采用水热合成法制备了α-MnO_2、β-MnO_2、γ-MnO_2和δ-MnO_2催化剂,运用N_2吸脱附实验、X射线衍射(XRD)、X射线光电子能谱(XPS)和H_2程序升温还原(H_2-TPR)等方法对催化剂进行了表征,并将催化剂用于催化完全氧化乙醇反应中,考察了不同晶型MnO_2催化剂催化氧化乙醇活性的差异,探讨了催化剂晶型结构与催化氧化活性的关联.结果表明,不同晶型的MnO_2催化剂催化氧化乙醇活性差异显著,活性顺序为α-MnO_2>δ-MnO_2>γ-MnO_2>β-MnO_2.系列表征结果显示,晶体结晶度和比表面积不是影响不同晶型MnO_2催化剂活性的主要原因,α-MnO_2催化剂具有的较高晶格氧浓度和较高的可还原性是其具有良好催化氧化乙醇活性的关键因素.α-MnO2,β-MnO2,γ-MnO2, andδ-MnO2 catalysts were synthesized by hydrothermal methods, and their catalytic performances towards the oxidation of ethanol were evaluated in detail. The as-synthesized MnO2 catalysts were characterized by N2 adsorption-desorption measurements, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and H2 temperature-programmed reduction （H2-TPR）. Theα-MnO2 catalyst showed the best activity of the catalysts tested for the combustion of ethanol and the trend in the activity of different MnO2 catalysts towards the oxidation of ethanol was of the orderα-MnO2〉δ-MnO2〉γ-MnO2〉β-MnO2. The effect of the crystal phase structure on the activity of the MnO2 catalysts was investigated. The XRD results showed that there were differences in the crystal inities of theα-,β-,γ-,δ-MnO2 catalysts, but these differences did not have a significant effect on their catalytic performances towards the oxidation of ethanol. The BET surface areas of theα-,β-,γ-,δ-MnO2 catalysts exhibited similar tendencies to their ethanol oxidation activities, although the results of standardization calculations showed that the surface area was not the main factor affecting their catalytical activities. The XPS results showed that the lattice oxygen concentration played an important role in defining the catalytic performance of the MnO2. The α-MnO2 catalyst showed the best reducibility of al of the MnO2 catalysts tested, as determined by H2-TPR. The excel ent performance ofα-MnO2 was attributed to its higher lattice oxygen concentration and reducibility, which were identified as the main factors affecting the activity of the MnO2 towards the complete oxidation of ethanol.

关 键 词：MnO2催化剂 低温催化氧化 乙醇完全氧化 挥发性有机物 晶格氧 

分 类 号：O643.36[理学—物理化学] X701[理学—化学]