面向ppb级苯系物检测的铈基多孔新材料构建及富集-催化-气敏协同机制研究

苯系物的污染极大地威胁到人体的健康和生命安全，迫切需要高效、低成本苯系物气体传感器。目前，半导体苯系物气体传感器受“ppb级全范围检测困难”，“选择性不高”和“稳定性不足”等限制，难以满足高标准检测的要求。基于此，申请开发一种铈基多孔纳米片包覆金属氧化物纳米纤维的核壳复合气敏材料，通过“选择性吸收富集”，“催化-敏感协同调控”和“敏感材料选择性保护”三个方面有效协同，实现对ppb级苯系物的高效检测。探索合成过程中的热力学和动力学机制，实现金属氧化物纳米纤维表面铈基多孔纳米片阵列可控生长。研究传感器构效关系，明晰铈基多孔纳米片孔道结构、过渡层厚度、孔径大小、片层尺寸、晶体结构、缺陷浓度、表面修饰等要素对苯系物敏感性能的影响规律。计算模拟结合气敏/催化测试及先进的原位表征结果分析，阐明复合气敏材料“富集-催化-气敏”协同作用机制。最终，为新一代高效苯系物半导体气体传感器开发提供理论和技术支持。

The pollution of benzene series (BTEX) vapors is a great threat to human health, indicative of the urgent need to detect BTEX with high efficiency and low cost. At present, the BTEX semiconductor gas sensor is difficult to meet the high standards due to the problems of “difficulty in achieving full-range detection of ppb level BTEX", "low selectivity" and "insufficient stability". Based on this, we try to develop a Ce-based porous nanosheets coated metal oxide (MOS) composite gas-sensitive material to realize efficient detection of ppb level BTEX, which can be attributed to the synergy of "selective absorption and enrichment of BTEX", "catalysis and sensitivity cooperative regulation" and "selective protection of MOS sensitive materials". The thermodynamic and kinetic mechanisms will be explored to realize controllable growth of Ce-based nanosheets array on MOS nanofibers. The structure-function relationship of sensors are studied to clarify the influence of different factors on gas sensitivity, including pore structure, transition layer thickness, porous size, nanosheets size, crystal structure, defect concentration and surface modification. The "enrichment-catalysis-gas sensitivity" mechanism of gas-sensitive materials is elucidated by calculation and simulation, combined with the results of gas-sensitive/catalytic test and in-situ characterization. Finally, the theoretical and technical foundation can be established for the development of the new generation of BTEX gas sensor.