摘要
采用共沉淀、溶胶-凝胶和水热3种方法制备了系列Ce0.75Zr0.25O2—75%Al2O3复合氧化物,以Ce0.75Zr0.25O2作参比,探讨氧化铝对铈锆复合氧化物性能的影响,应用BET、XRD、H2-TPR与O2-TPD对样品进行表征。XRD结果显示,铝离子完全进入到了铈锆固溶体晶格中,Ce0.75Zr0.25O2—75%Al2O3复合氧化物形成了单一的立方萤石结构,且在1173K老化后仍未出现分相现象,结构稳定。TPR和TPD结果表明,氧化铝的存在显著提高了铈锆固溶体的氧化还原和热稳定性,其中,用共沉淀法制备Ce0.75Zr0.25O2—75%Al2O3的O2-TPD量为66.393μmol/g,是同法制Ce0.75Zr0.25O2的2倍多,而其还原温度也较Ce0.75Zr0.25O2低70K左右。
Three different methods,co-precipitation,sol-gel and hydrothermal method,have been used to prepare Ce0.75Zr0.25O2—75%Al2O3.The influence of Al2O3 doping on CexZr1-xO2 solid solution in comparison with Ce0.75Zr0.25O2 were discussed.The samples were characterized by means of BET,XRD,TPR and O2-TPD techniques.The XRD results showed that Al3＋ can entered the lattice of CexZr1-xO2 solid solution entirely,which led to a better aluminum dispersion and formed the single cubic fluorite structure,and the compound can still keep the stable structure even after 1 173 K high temperature aged.According to the results of TPR and TPD,the exist of Al2O3 can largely improve the redox performance and thermo-stability of the samples.The Ce0.75Zr0.25O2—75%Al2O3 prepared by co-precipitation exhibits high O2-TPD amount of 66.393 μmol/g,which is more than twice of the corresponding Ce0.75Zr0.25O2,and its TPR temperature is also 70K lower than that of Ce0.75Zr0.25O2.
基金
广东高校科技成果转化资助项目(cgzhzd0803)
广东省自然科学基金资助项目(8151009101000025)
广东省社会发展科技资助项目(2007B030102006)
