xAu/α-MnO_2催化剂的结构及催化氧化VOCs气体性能  

xAu/α-MnO_2 Catalysts:Structure and Catalytic Oxidation of Benzene and Toluene

作　　者：叶青[1] 霍飞飞[1] 王海平[1] 王娟[1] 王道[1] 

机构地区：[1]北京工业大学环境与能源工程学院,北京100124

出　　处：《高等学校化学学报》2013年第5期1187-1194,共8页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20777005);北京市自然科学基金(批准号:8082008)资助

摘　　要：以NaOH为沉淀剂,采用沉积-沉淀法制备了α-MnO2负载Au催化剂xAu/α-MnO2(x=1.0%～7.0%,质量分数),利用X射线衍射(XRD)、N2吸附-脱附、H2程序升温还原(H2-TPR)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等技术对所得样品进行了表征,并对其催化氧化挥发性有机化合物(VOCs,苯和甲苯)的性能进行了研究.XRD结果表明,负载Au对α-MnO2载体结构影响不大,但对其晶粒大小和比表面积略有影响.随着Au含量的增加,α-MnO2结晶度增强,颗粒增大,Au粒径明显增大.XPS结果表明,随着Au负载量的增加,xAu/α-MnO2的晶格氧(O2-),Mn4+和Au3+的浓度增加.H2-TPR结果表明,由于贵金属的溢氢作用,Au明显提升了xAu/α-MnO2的还原能力,其中3%Au/α-MnO2的还原能力最强.负载Au明显影响xAu/α-MnO2的催化性能,xAu/α-MnO2的催化性能与Au的颗粒分散性、低温还原性能及表面氧物种密切相关,其中3%Au/α-MnO2显示出最佳活性,其催化氧化苯和甲苯的T100分别为280和250℃.a-MnO2-supported gold catalysts（xAu/a-Mn02, x = 1.0%--7.0%, mass fraction） were prepared by deposition-precipitation method using NaOH as precipitation agent and characterized by X-ray diffraction （XRD）, N2 adsorption-desorption measurement, H2 temperature-p electron microscopy（TEM） and X-ray photoelectron spectroscopy （XPS）. Catalytic activities of the materials were evaluated for the oxidation of benzene and toluene. The sizes of Au particle and o-MnO2 support were related with the Au loading over xAu/a-MnO2 samples and increased with Au loading. The result of XPS showed that the molar ratios of 02-/O, Mn4＋/Mn3 and Au3/Au increase with adding of Au. It was shown that the loading of gold on ot-MnO2 could significantly modify the catalytic activities. The catalytic performance of xAu/ ot-MnO2 strongly depended upon the Au loading , among which 3%Au/a-MnO2 performed the best activity, ＇100 = 280,250℃ for the catalytic oxidation of benzene and toluene, respectively. The excellent performance of 3%Au/a-MnO2 was associated with the highly dispersed Au, good low-temperature reducibility, and synergism at the interface of Au and MnO2 nanodomains.

关 键 词：AU α-MnO2催化剂 还原性能 协同作用 苯 甲苯 催化氧化 

分 类 号：O643.32[理学—物理化学]