聚乙二醇辅助下的La-Co-O复合氧化物合成及其对苯的完全氧化性能研究（英文）  

Synthesis of La-Co-O Mixed Oxides via Polyethylene Glycol-Assisted Co-Precipitation Method for Total Oxidation of Benzene

作　　者：魏笑峰[1,2] 李达林[1] 肖益鸿[1] 蔡国辉[1] 戴武[1] 谢增鸿[2] 魏可镁[1] 

机构地区：[1]福州大学化肥催化剂国家工程研究中心,福建福州350002 [2]福州大学化学学院,福建福州350108

出　　处：《光谱学与光谱分析》2016年第9期3062-3067,共6页Spectroscopy and Spectral Analysis

基　　金：National Science Foundation(40976071and 21377024);Key S&T Project of Fujian Province(2014H6015);the Program from the Fujian Education Department(JA12023)

摘　　要：以聚乙二醇(PEG)作为分散剂,采用共沉淀法合成La-Co-O复合氧化物,考察添加不同分子量的PEG(0,2 000,6 000,20 000g·mol^(-1))对复合氧化物的物化性质及苯完全氧化性能的影响。采用N_2物理吸附、XRD、SEM、H_2-TPR、O_2-TPD和XPS进行催化剂表征。苯完全氧化反应结果显示催化剂活性顺序为LCO-PEG6000>LCO>LCO-PG20000>LCO-PG2000,LCO-PEG6000催化剂在383℃时对苯的转化率达到99%,比LCO低126℃。N_2物理吸附实验表明所制备的样品的SBET均为9~10m·g^(-1)。XRD分析显示合成的催化剂均为LaCoO_3钙钛矿主相伴生少量La_2O_3和Co_3O_4杂相,但添加PEG有利于钙钛矿主相的形成。尤其是添加PEG6000有效地抑制了催化剂颗粒的团聚,合成的样品颗粒均匀且尺寸最小。H_2-TPR和O_2-TPD结果表明该催化剂具有更高的还原性能和晶格氧迁移能力,同时XPS分析显示表面活性Co^(3+)含量最高,这些性质使其具有最高的催化氧化活性。La-Co-O mixed oxides （LCO）were prepared by co-precipitation method with the presence of poly-ethylene glycol （PEG）as dispersant.The influence of adding different molecular weight of PEG （0,2 000, 6 000,20 000 g·mol-1 ）on the physicochemical and catalytic properties of La-Co-O mixed oxides for total ox-idation of benzene was investigated.The samples were characterized by means of N2 physical adsorption,X-ray diffraction （XRD）,scanning electron microscopy （SEM）,temperature-programmed reduction by H2 （H2-TPR）,temperature-programmed desorption of O2 （O2-TPD）,and X-ray photoelectron spectroscopy （XPS）. The order of catalytic activity was found to be LCO-PEG6000〉LCO〉LCO-PG20000〉LCO-PG2000.Partic-ularly,LCO-PEG6000 exhibited benzene conversion of 99% at temperature as low as 383 ℃,which was 126℃ lower than that of LCO.The characterization result reveals that all samples had a BET surface area of about 9-10 m2 ·g-1 .The XRD result shows that on all samples LaCoO3 perovskite was mainly formed together with a small amount of La2 O3 and Co3 O4 .The addition of PEG was favorable for the formation of LaCoO3 per-ovskite.Particularly,the addition of PEG-6000 effectively suppressed the agglomeration of LaCoO3 perovs-kite,giving rise to small and uniform particles as observed by SEM.Moreover,the results of H2-TPR and O2-TPD indicate that the obtained La-Co-O mixed oxides showed higher reducibility and lattice oxygen mobility, and the Co 2p XPS analysis suggests that more surface Co3＋ active species were presented by the addition of PEG-6000.These properties are thought to contribute to the high activity in benzene total oxidation.

关 键 词：复合氧化物 LACOO3 聚乙二醇 共沉淀法 催化燃烧 苯完全氧化 

分 类 号：O643.36[理学—物理化学]