α-Fe2O3基纳米材料高能表面金属原子结构、配位与气体传感性能的关联性及其机制研究

基于提高α-Fe2O3纳米材料表面不饱和金属原子数量增强气敏性能的思想，本项目采用水热/溶剂热和溶液高温热反应，利用晶面控制剂的选择性吸附，制备暴露不同高能Fe-Fe2O3晶面的α-Fe2O3纳米材料。通过去除Fe-Fe2O3表面的控制剂和羟基，在Fe-Fe2O3表面选择性掺杂Al、Sn和负载Ag增强其对氢气、乙醇、一氧化碳和氨气等气体的响应特性，获得高灵敏度α-Fe2O3基传感材料。采用SEM、XRD、TEM、IR、XPS、SPM和球差校正透射电镜等表征α-Fe2O3基纳米材料，结合密度泛函理论计算，确定其形貌、晶体结构、暴露晶面、Fe-Fe2O3及其掺Al、Sn与负载Ag的表面结构。分析α-Fe2O3基纳米材料表面金属原子结构、配位与气敏性能的关系，在分子、原子水平上阐明气体传感反应机制，揭示气敏性能增强的根本原因，为高性能半导体氧化物气体传感材料与器件的研究提供新策略和理论依据。

Based on a thought of enhancing sensing performances by increasing the number of unsaturated metal atoms at α-Fe2O3 nanostructured nanomaterial surfaces, α-Fe2O3 nanostructured nanomaterials with exposed various high energy Fe-Fe2O3 facets are synthesized by utilizing the selective absorption of crystal plane control agents by the hydrothermal, solventhermal and high temperature thermal reaction methods. Gas sensing properties of the α-Fe2O3 nanostructured nanomaterials toward hydrogen, ethanol, carbon monoxide, ammonia and other gases were enhanced by removing the crystal plane control agents and hydroxyl groups at the Fe-Fe2O3 surfaces, doping with Al or Sn element and decorating with Ag nanoparticles at the high energy Fe-Fe2O3 surfaces selectively, to obtain high sensitivity α-Fe2O3 based nanostructured materials. The α-Fe2O3 based nanostructured materials are characterized by SEM, XRD, TEM IR，XPS，SPM, corrected scanning spherical aberration TEM and other technologies, structure of the high energy Fe-Fe2O3 and Fe-Fe2O3 crystal facets doping with Al or Sn are investigated by density functional theory. Thus, the morphology, crystal structure, exposed facets and structures of the Fe-Fe2O3 and Fe-Fe2O3 surfaces doping with Al or Sn and decorating with Ag are confirmed. The correlation between the gas sensing properties and the surface metallic atom structure and coordination of α-Fe2O3 based nanostructured materials are analyzed, the sensing reaction mechanism is presented at atomic and molecule level, and the fundamental reason for enhancing sensing performance is revealed. A new theory and a strategy are provided for design and fabrication of the metal oxide semiconductor oxide gas sensing materials and devices with high performances.