富集/测量一体式痕量甲醛气体传感器的研究

Recently, the trace concentration of indoor formaldehyde has been received great attention with the keep growing human consciousness about self-health. It is extremely necessary to develop a high sensitive gas sensor which can easily detect trace formaldehyde to meet the increasing demand of indoor air quality. In this application, a new trace formaldehyde sensor was proposed by highly integrate micro electro mechanical system (MEMS) preconcentrator and solid state electrolyte gas sensor using LaMnO3 as key research object. The following research will be gradually expanded: 1. Modified LaMnO3 will be synthesis by doping and combination, the influence of modified method on LaMnO3 surface will be investigated. 2. The mechanism of formaldehyde adsorption, desorption and catalyst on the surface of modified LaMnO3 will be researched. 3. The effects of various factors on the enrichment ratio of formaldehyde perconcentrator will be discussed and the modified LaMnO3 will be used as adsorbent. 4. A formaldehyde sensor combining with enriched and sensing functions will be developed by added a Pt reference electrode and Pt wires to above preconcentrator. Then, the adsorbent layer will be used as sensing electrode, meanwhile, the sensing mechanism of new sensor will be researched. In generally, this work will provide a new method and theory to realize the detection of indoor trace formaldehyde.

近年来，随着人们自我健康意识的不断提高，室内痕量甲醛的含量受到了极大的关注。为实现对室内痕量甲醛方便、准确的测量，极有必要研发出一种灵敏度高、适合大范围推广的甲醛气体传感器。本项目以LaMnO3为核心研究对象，借鉴微机电系统（MEMS）富集器的结构，提出了一种富集器与固体电解质气体传感器高度结合的新型痕量甲醛气体传感器。整个研究将按如下顺序依次展开：1.对LaMnO3进行掺杂和复合改性，研究改性方式对材料表面状态的影响；2.甲醛在LaMnO3改性材料表面吸附/脱附/催化机理的研究；3.将LaMnO3作为甲醛富集器的吸附剂，研究各种因素对富集率的影响；4.通过在富集器上增加Pt参考电极和Pt导线，将富集器的吸附层作为传感器的敏感电极，构建一种富集/测量一体式的痕量甲醛气体传感器，研究新型传感器的敏感机理。通过本项目的研究力争为室内痕量甲醛的检测提供一种方便、有效的新型测量技术和理论支持。

本项目针对室内痕量甲醛检测困难的问题，建立了一套痕量甲醛预富集的传感检测系统。针对活性碳、La0.8Sr0.2MnO3对甲醛气体的吸附脱附特性进行了表征分析，研究吸脱附温度、吸附剂表面状态对甲醇吸附能力的影响，实现了对痕量甲醛的检测。从电化学传感器的角度解释了甲醇的电化学催化敏感机理。在此基础上为了进一步提高传感器对各种VOCs的选择性、研究背景气中氧浓度对传感器敏感性能的影响，开展了使用电压调制、温度调制、光照调制等方法对传感器选择性的研究，研究结果表面通过外加额外的能量可以进一步提高传感器对甲醛等各类VOCs的选择性。使用激光对电化学传感器的三相界面进行了量化刻蚀，研究了电化学传感器三相界面粗糙度对传感器催化活性的影响。研究结果表面三相界面的粗糙越高传感器的活性越高。本项目的研究工作为进一步提高全固态电化学传感器的检测下限性选择性提供了理论和实验基础。已有11篇论文发表在《Sensors and Actuators B: chemicals》、《ACS Sensors》、《Ionics》、《IEEE Sensors Journey》《传感器与微系统等》等国内外期刊上，已获国家发明专利授权2项、实用新型1项。