人呼气检测是从疾病原理出发，探测与疾病相关的代谢呼出气体成分和含量诊断方法，这种非侵入式的医疗检测可做到实时在线低成本的自我健康状况监测。为保证气体传感器检测的准确性和长期稳定性，最关键因素是敏感材料设计。本项目基于人呼气检测气体传感器，围绕改善灵敏度、检测限、交叉选择性、和抗湿性这一主线，通过结构调控和表面修饰提高敏感材料的气敏特性。利用静电纺丝和水蒸气热处理制备出具有多级孔结构、晶粒尺寸小且贵金属纳米颗粒均匀分布的Metal@ZnO-WO3复合氧化物纳米纤维。系统研究不同晶粒尺寸、贵金属纳米颗粒分散度、多级孔结构和双异质结对传感器灵敏度变化规律，从结构调控和表面改性揭示气敏增强机制。探索在敏感层表面引入水分过滤层对传感器的抗湿性改善。为能够自下而上设计金属氧化物半导体气敏传感器用于人体呼气检测提供理论指导和技术支持，为提升其在呼气临床诊断方面的性能检测奠定研究基础。

Human breath detection is a diagnostic method which is based on the principle of disease, and detects the components and content of disease-related metabolic exhaled gas. This non-invasive medical test can achieve real-time online and low-cost self-health monitoring. To ensure the accuracy and long-term stability of gas sensor detection, the most critical factor is the design of sensitive materials. This project is based on the human breath detection gas sensor, around the main line of improving sensitivity, detection limit, cross-selectivity, and moisture resistance, which improves the gas sensitivity of sensitive materials through structural modulation and surface modification. Metal@ZnO-WO3 composite oxide nanofibers with multi-stage pore structure, small particle size and uniform distribution are prepared by electrospinning and water-steam treatment. The variation of the grain size, noble metal nanoparticle dispersion, multi-stage pore structure and double heterojunction on the resistance and sensitivity of the sensor are systematically studied. The gas sensitivity enhancement mechanism is revealed from the structural regulation and surface modification. The improvement effect of moisture resistance of the sensor is explored after introducing moisture filter layer on the surface of sensitive layer. This project provides theoretical guidance and technical support for the bottom-up design of MOS gas sensor for human breath detection, and lays a research foundation for improving the detection performance of MOS gas sensor in clinical diagnosis of exhalation.