Abstract: Nanosized γ-Fe₂O₃ and γ-Fe₂O₃/SiO₂ complex oxides were prepared by the sol-gel method, and sensing elements were fabricated. Phase composition, grain size, part
icle size distribution of the nanosized oxides were characterized by TG-DTA,X
RD,TEM and Zetasize distribution respectively. The sensitivity of the sensing el
ements to CO, H₂, C₂H₄, C₆H₆ and the effects of calcination temperature on the sensitivity of two typical elements were examined. The operating temperature of elements to different gases was obtained. The results showed that phase transition temperature, thermal stability,catalytic activity and gas sensitivity of γ-Fe₂ O₃ were enhanced due to the SiO₂ present. The thermal stability of gas sensing and catalytic materials based on γ-Fe₂O₃ was expected to be basically solved.

摘要： 用溶胶-凝胶法制备了纳米γ-Fe₂O₃及γ-Fe₂O₃/SiO₂复合氧化物，用热重-差热分析 (TG-DTA)、X射线衍射 (XRD)、透射电镜 (TEM)和二次粒度分布对纳米粒子进行表征，并考察了γ-Fe₂O₃、γ-Fe₂O₃/SiO₂敏感材料对CO、H₂、C₂H₄、C₆H₆等气体的敏感系数及其焙烧温度对敏感系数的影响，并选择了敏感材料对气体检测的最佳工作温度.结果表明，γ-Fe₂O₃/SiO₂纳米复合氧化物中SiO₂对提高γ-Fe₂O₃的相变温度、加强热稳定性及提高催化和气体敏感系数起很大作用.