氢化增强暴露{111}晶面NiFe_(2)O_(4)八面体的气体传感性能及其传感机理

Increasing Sensing Sensitivity of NiFe_(2)O_(4){111}Surface by Hydrogenation and the Sensing Reaction Molecule Mechanism

以六水合氯化铁、六水合氯化镍、氢氧化钠和乙二醇为原料,在200℃下水热合成10 h,制得暴露{111}晶面的NiFe_(2)O_(4)八面体。将该产物用于甲醇和三乙胺的传感反应中均表现出良好的气敏活性。通过加氢去除表面的—OH和Cl-离子后,其气体传感性能得到进一步提高。传感性能的增强是由于表面Cl-离子和—OH基团的去除,导致NiFe_(2)O_(4)表面3配位不饱和Fe原子数量增加。以不饱和金属原子作为传感反应的活性位点,提出了一种原子和分子水平的气体传感机制。此传感机制对于设计和制备先进的气体传感器具有重要意义。

NiFe_(2)O_(4)octahedron with exposed{111}crystal planes was prepared by hydrothermal synthesis at 200℃for 10 hours using ferric chloride hexahydrate,nickel chloride hexahydrate,sodium hydroxide and ethylene glycol as raw materials.The product showed good gas sensitive activity in methanol and triethylamine sensing reactions.The gas sensing performance is further improved by removing the—OH and Cl-ions from the surface by hydrogenation.The enhancement of sensing performance is due to the removal of surface Cl-ions and—OH groups,which leads to the increase of the number of 3-coordination unsaturated Fe atoms on the surface of NiFe_(2)O_(4).Using unsaturated metal atoms as the active site of sensing reaction,a gas sensing mechanism at atomic and molecular levels is proposed.The sensing mechanism of 3-coordination unsaturated iron atoms as reaction sites is of great significance for understanding the mechanism of catalytic reactions such as sensing and the design and preparation of advanced gas sensing sensors and catalysts.