王殿二,李国波,李超,徐新,王玲,张亚平.商业V2O5-WO3/TiO2催化剂重金属(Pb、Cu、Zn)中毒机理研究[J].分子催化编辑部,2019,33(6):508-523
商业V2O5-WO3/TiO2催化剂重金属(Pb、Cu、Zn)中毒机理研究
Commercial V2O5-WO3/TiO2 Catalysts for Heavy Metal (Pb, Cu, Zn) Poisoning Mechanism
投稿时间:2019-09-10  修订日期:2019-10-23
DOI:
中文关键词:  失活  SCR  重金属  氨吸附
英文关键词:deactivation  SCR  heavy metal  ammonia adsorption
基金项目:江苏省重点研发计划(社会发展)面上项目(BE2017716)
作者单位E-mail
王殿二 光大环境修复(江苏)有限公司, 江苏 南京 211100  
李国波 东南大学能源与环境学院 能源热转换及其过程测控教育部重点实验室, 江苏 南京 210096  
李超 光大环境修复(江苏)有限公司, 江苏 南京 211100  
徐新 光大环境修复(江苏)有限公司, 江苏 南京 211100  
王玲 东南大学能源与环境学院 能源热转换及其过程测控教育部重点实验室, 江苏 南京 210096  
张亚平 东南大学能源与环境学院 能源热转换及其过程测控教育部重点实验室, 江苏 南京 210096 amflora@seu.edu.cn 
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中文摘要:
      采用浸渍法制备了不同含量重金属(Pb,Cu和Zn)中毒商业V2O5-WO3/TiO2催化剂,并对催化活性进行评估,重金属可明显导致催化活性降低.随着重金属浓度的增加,催化剂的失活程度加剧,而Cu和Zn的中毒效应低于Pb.结合XRD、BET、SEM、NO-TPD、NH3-TPD、H2-TPR和in situ DRIFTS等方法对重金属中毒前后催化剂的理化性质进行分析.分析结果表明,失活是由化学和物理中毒的耦合作用引起的.相比于Fresh催化剂,中毒催化剂微孔和中孔有明显堵塞现象,BET比表面积减小,而中毒前后催化剂结晶度几乎没有变化,而中毒催化剂的表面覆盖了一层白色晶体,这可能导致活性位点被占据并阻碍NH3在催化剂表面的吸附.in situ DRIFTS结果表明,重金属中毒后Brønsted和Lewis酸位点的强度减弱,尤其是Brønsted酸位点.此外,随着重金属含量的增加,中毒催化剂表面NO2吸附量逐渐增加,从而促进N2O的形成.H2-TPR结果显示,还原峰的强度随着还原温度的升高而增强,表明重金属导致催化剂中的活性组分更难以参与SCR反应.
英文摘要:
      Commercial V2O5-WO3/TiO2 catalysts poisoned by heavy metals (Pb, Cu, and Zn) poisoned with different contents were prepared by the impregnation method, and the catalytic activity was evaluated, the heavy metal can significantly reduce the catalytic activity. As the concentration of heavy metals increases, the degree of deactivation of the catalyst increases, and the poisoning effect of Cu and Zn is lower than that of Pb. XRD, BET, SEM, NO-TPD, NH3-TPD, H2-TPR and in situ DRIFTS were used to analyze the physicochemical properties of the catalyst before and after heavy metal poisoning. The micropores and mesopores of the poisoned catalyst have obvious clogging phenomenon, the BET specific surface area is reduced, this results show that inactivation is caused by the coupling of chemical and physical poisoning. Compared to the fresh catalyst, the mand the crystallinity of the catalyst is almost unchanged before and after poisoning, and the surface of the poisoned catalyst is covered with a layer of white crystals, which may cause activity the sites are occupied and hinder the adsorption of NH3 on the catalyst surface. In situ DRIFTS results showed that the intensity of the Brønsted and Lewis acid sites weakened after heavy metal poisoning, especially the Brønsted acid sites. In addition, as the content of heavy metal increases, the amount of NO2 adsorbed on the surface of the poisoned catalyst gradually increases, thereby promoting the formation of N2O. The H2-TPR results showed that the intensity of the reduction peak increased with the increase of the reduction temperature, indicating that heavy metals caused the active components in the catalyst to be more difficult to participate in the SCR reaction.
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