基于多孔矿物材料基板的瓦斯气体传感器及其敏感机理研究

At present, the substrates used for preparing gas sensing nanomaterials show some limitations such as relatively single material and high cost. Thus, this project aims to develop porous mineral substrates based on low-cost natural porous minerals. Porous film and single crystal oxide semiconductor nanomaterials with high surface-to-volume ratio and surface activity will be prepared on the porous mineral substrates by its pore channel effect and recombination effect. The microstructure and growth mechanism of these gas sensing nanomaterials will be analyzed. Then the mine gas sensing properties of these nanomaterials will be investigated after completing the fabrication of gas sensors by dispersing the nanomaterials on the electrodes. Based on the corresponding sensing results, the relationships among pore characterization of porous mineral substrate, nanomaterial microstructure, and gas sensing property will be discussed so as to analyze the adsorption-desorption reaction kinetics between the detected gases and gas sensing nanomaterials. The possible reaction mechanism models are expected to be built so as to further improve gas sensing theory of oxide semiconductor nanomaterials. The outcomes of this project including experimental data and theoretical analysis will be the base of developing new-type mine gas sensors with low operating temperature, high selectivity, quick response speed and low cost, which have important significance to improve the safety and environment protection in the process of mine industry in China.

针对目前制备纳米气敏材料的基板材质相对单一以及价格昂贵等问题，本项目拟以价格低廉的天然多孔矿物材料为原料制备多孔矿物材料基板，利用多孔矿物材料基板的孔道效应和重组效应，在基板上优化制备具有高比表面积和表面活性的氧化物半导体型多孔化薄膜和单晶化纳米气敏材料，并对这些纳米气敏材料的结构特性和生长机理进行分析；随后将纳米气敏材料沉积或分散到电极上，制备成气体传感器以考察对瓦斯主要成分甲烷的气敏特性；依据气敏特性检测的相关研究结果，阐明多孔矿物材料基板孔隙特征、纳米气敏材料微观结构与气敏特性之间的关联性，构建被检测气体与气敏材料的吸附-解吸反应机制模型，完善氧化物半导体气体传感器的气敏反应理论体系。本项目将为开发新型基于多孔矿物材料基板的具有低工作温度、高气体选择性、快响应速度、低生产成本等优点的瓦斯气体传感器奠定理论及实验基础，研究结果对提高我国矿业生产过程中的安全环保具有重要意义。

针对目前制备纳米气敏材料的基板材质相对单一以及价格昂贵等问题，本项目以价格低廉的天然多孔矿物材料（硅藻土、偏高岭土、沸石等）为原料，采用模压-烧结工艺优化制备出具有强度高、孔洞分布有序、耐腐蚀性强等特点的多孔矿物材料基板。利用多孔矿物材料基板的孔道效应、重组效应和界面调控效应，采用气相法和液相法在基板上优化制备出具有比表面积大、表面活性高、形貌结构多样的氧化物半导体纳米气敏材料，如SnO2纳米线、ZnO纳米棒、In2O3纳米棒阵列等。通过气相法中的“气-液-固机制”和液相法中的“溶解-结晶机制”对纳米气敏材料的结晶特性和生长机理进行了分析，从而达到改善纳米气敏材料结构和性能的目的。将所获纳米气敏材料沉积或分散到电极上制备成气敏元件，考察了对矿业有毒有害气体如CH4、H2S、SO2、NO2等的气敏特性，揭示了利用多孔化薄膜的“肖特基势垒限制传输效应”、单晶化纳米材料的“电子耗尽层”或“空穴积累层”特性、贵金属掺杂的“化学效应”和“电子效应”以及异质结构建所产生的“费米能级电荷转移效应”可以显著提升所获纳米气敏材料的性能。依据气敏特性检测的相关研究结果，阐明了多孔矿物材料基板孔隙特征、纳米气敏材料微观结构与气敏特性之间的关联性，构建了被检测气体与纳米气敏材料之间的吸附-解吸反应机制模型。通过与常规基板表面所获纳米气敏材料进行对比分析，基于多孔矿物材料基板界面调控所获的纳米气敏材料表现出更加优越的灵敏度、响应/恢复速度、选择性及稳定性，为新型气体传感器的开发提供了界面可控、性能稳定、成本低廉等优点的基板衬底。本项目为开发新型基于多孔矿物材料基板的具有低工作温度、高气体选择性、快响应速度、低生产成本等优点的矿业有毒有害气体传感器奠定理论及实验基础，研究结果对提高我国矿业生产过程中的安全环保具有重要意义。