Ce_(0.75)Cu_(0.25-x)O_2固溶体催化剂用于PVOCs催化燃烧

Ce_(0.75)Cu_(0.25-x)O_2 solid solution catalyst for catalytic combustion of PVOCs

通过柠檬酸络合法制得Ce0.75Cu0.25-x O2固溶体催化剂,采用X射线衍射、X射线光电子能谱和H2-程序升温还原对催化剂性能进行研究,考察催化剂对苯基挥发性有机物的催化燃烧活性。结果表明,催化剂中大量CuO溶入CeO2晶格中形成Ce0.75Cu0.25-x O2固溶体,固溶体的形成削弱了催化剂中的Cu—O和Ce—O键,提高了相应氧化物的低温可还原性,也提高了催化剂表面活性氧物种含量,从而提高了催化剂上苯基挥发性有机物的催化燃烧活性。在反应温度250℃和275℃时,Ce0.75Cu0.25-x O2固溶体催化剂上甲苯和二甲苯的催化燃烧转化率分别为97.6%和95.0%。Ce0.75Cu0.25-x O2催化剂上苯在280℃时催化燃烧转化率仅为61.0%,这可归因于苯分子稳定的芳香环结构不易被破坏。

Ce0.75Cu0.25-xO2 Solid solution oxide catalyst was prepared by citric acid complexation method and characterized by XRD,XPS and H2-TPR.The catalytic combustion performance of Ce0.75Cu0.25-xO2 catalyst for phenyl volatile organic compounds （PVOCs-benzene,toluene,and xylene） was investigated.The results indicated that copper oxide dissolved in CeO2 crystal lattice to form Ce0.75 Cu0.25-xO2 solid solution catalyst.Cu-O and Ce-O chemical bonds were weakened because of the formation of the solid solution,which enhanced the low temperature reducibihty of the corresponding oxide,the contents of surface active oxygen species on Ce0.75 Cu0.25-x O2 catalyst and catalytic combustion activity of PVOCs.The catalytic combustion conversion of toluene and xylene on Ce0.75 Cu0.25-xO2 catalyst reached 97.6％ and 95.0％ at 250 ℃ and 275 ℃,respectively.The catalytic combustion conversion of benzene on Ce0.75Cu0.25-xO2 catalyst was only 61.0％ at 280 ℃,which attributed to a highly stable aromatic ring structure of benzene molecules.