铈锆固溶体CexZr1-xO2上H2S的选择性催化氧化性能  

Selective catalytic oxidation of H2S over cerium-zirconium solid solutions CexZr1-xO2

作　　者：孙宇 张鑫 张凤莲 蒋国霞[1] 魏征 郝郑平[1,2] Sun Yu;Zhang Xin;Zhang Fenglian;Jiang Guoxia;Wei Zheng;Hao Zhengping(Key Laboratory of Environmental Nanotechnology and Health Effects,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;National Engineering Laboratory for VOCs Pollution Control Material & Technology,Research Center for Environmental Material and Pollution Control Technology,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]中国科学院生态环境研究中心环境纳米技术与健康效应重点实验室,北京100085 [2]中国科学院大学环境材料与污染控制技术研究中心挥发性有机物污染控制材料与技术国家工程实验室,北京101408

出　　处：《工业催化》2020年第10期19-27,共9页Industrial Catalysis

基　　金：国家自然科学基金项目(21976176,21507148);国家重点研发计划项目(2018YFA0209302)。

摘　　要：采用共沉淀法合成一系列具有不同Ce/Zr物质的量比的铈锆固溶体CexZr1-xO2,考察Ce/Zr比例对H2S选择氧化反应催化活性的影响。通过XRD、BET、Raman、XPS、CO2-TPD、O2-TPD、H2-TPR等手段对铈锆固溶体的晶体结构、表面性质、碱性位以及氧化还原性等进行表征。结果表明,所有的铈锆固溶体催化剂均可以在化学计量比的氧气下具有优良的低温催化活性,催化活性随着Ce/Zr比例的提高而增加,其中Ce0.9Zr0.1O2活性最高,(160~260)℃转化率均保持在95%以上,在180℃时硫收率可达到97%,这主要是因为Ce0.9Zr0.1O2具有最多的中度碱性位、活性位数量和强的氧化还原性。同时推测Ce4+为催化反应的活性位,并遵循氧化还原机理。此外,催化剂的失活主要是由于催化剂表面生成硫酸盐物种,消耗了活性组分Ce4+。A series of cerium zirconium solid solutions CexZr1-xO2 with different Ce/Zr molar ratios(x=0.9,0.7,0.5,0.3,0.1)were synthesized by co-precipitation method.The effects of the Ce/Zr molar ratio on the catalytic activity of H2S selective catalytic oxidation were investigated.XRD,BET,Raman,XPS,CO2-TPD,O2-TPD,H2-TPR were used to characterize the crystal structure,surface properties,basic sites and redox properties of cerium zirconium solid solutions.The cerium zirconium solid solution catalysts have excellent low-temperature catalytic activities under stoichiometric oxygen.The catalytic activity grows with the increase of Ce/Zr ratio where Ce0.9Zr0.1O2 has the highest catalytic activity.H2S conversion at(160-260)℃is kept above 95%and the sulfur yield can reach 97%at 180℃.The reason is that Ce0.9Zr0.1O2 has the largest amount of moderate basic sites and active sites,at the same time,the strongest redox properties.Moreover,Ce4+is speculated as the active site of the catalytic reaction and follows the redox mechanism.Additionally,the deactivation of the catalyst is mainly due to the formation of sulfate species on the catalyst surface,consuming the active site Ce4+.

关 键 词：催化化学 铈锆固溶体 H2S选择氧化 铈锆物质的量比 催化机理 

分 类 号：O643.36[理学—物理化学] TQ426.94[理学—化学]