石墨烯负载的氧化锡量子点气敏反应特性与影响机制研究

Gas reactivity of metal oxide semiconductors (MOSs) plays a key role in the determination of gas-sensing properties, such as operating temperature and selectivity. However, the exact mechanism is currently unclear. Construction relationship between “structural characteristics” and “gas reactivity” of MOSs by investigation of adsorption behavior of gases on MOSs is helpful to understand the effects of gas reactivity on gas-sensing properties. Tin oxide quantum dots (SnO2 QDs) are ideal research model material, due to their easily controlled structural characteristics. However, their gas reactivity is difficult to be obtained from the gas-sensing properties of sensor devices, which are dramatically affected by the agglomeration of SnO2 QDs as well as the morphology and thickness of gas-sensitive films. In this project, SnO2 QDs were loaded on the surfaces of grapheme, and the gas reactivity of SnO2 QDs can be characterized through the resistance change of graphene. During the study, the gas reactivity of SnO2 QDs with different structural characteristics was firstly systematically investigated towards various target gases at different operating temperatures, and the adsorption behaviors of gases on SnO2 QDs under the same conditions also were studied. Based on the above system data, the relationship between “structural characteristics” and “gas reactivity” of SnO2 QDs was studied to obtain the key factors that influence gas reactivity and influencing law within. We believe that the implementation of this project will not only provide a basis understanding of adsorption behavior of gases on the gas-sensing materials such as quantum dots, but also provide theoretical support for the regulating of gas-sensing properties of gas-sensing materials.

金属氧化物气敏材料的气敏反应特性是决定传感器工作温度及选择性的关键，但目前还缺乏深刻认识和理解。通过研究气体在气敏材料表面的气敏反应过程，构建气敏材料“结构特性-气敏反应特性”关联模型，有助于理解其气敏反应特性的影响机制。氧化锡量子点结构特性易调控、表征是研究气敏反应特性较理想的模型材料，但存在难以利用器件气敏性能准确表征其气敏反应特性的困扰。本项目拟将氧化锡量子点负载在石墨烯表面，利用气体与氧化锡量子点发生气敏反应而导致的石墨烯电阻变化来间接表征其气敏反应特性。通过系统表征不同结构特性氧化锡量子点在不同温度下对不同目标气体的气敏反应过程和气敏反应特性，利用化学吸附热与吸附态来构建氧化锡量子点“结构特性-气敏反应特性“关联模型，获得影响其气敏反应特性的规律与机制。本项目可深入理解量子点等气敏材料气敏反应过程的物理、化学内涵，为气敏材料的性能调控提供一定理论支撑。

金属氧化物气敏材料的气敏反应特性是决定传感器工作温度及选择性的关键，但目前还缺乏深刻认识和理解。通过研究气体在气敏材料表面的化学吸附行为，构建气敏材料“结构特性”与“气敏反应特性”的关联模型，有助于理解其气敏反应特性的影响机制。本项目开展了敏感材料制备方法研究，掌握了SnO2 QDs/Graphene、Ag3PO4、多孔纳米ZnO等敏感材料的结构可控制备方法；发展了粒径尺寸、表面化学结构、三维结构等结构特性调控方法，研究了其对气敏反应特性的影响规律与机制，对气体在敏感材料表面的气敏反应行为获得了一定的认识：.1）表面缺陷是敏感材料气敏活性的来源。例如，Sn2+掺杂SnO2对乙醇、NO2的气敏活性更高；利用MOF前驱体制备的ZnO由于含有丰富的氧缺陷而对H2S具有优异的选择响应性。.2）表面化学结构（即表面原子）对敏感材料气敏选择性有重要影响。例如，通过模拟计算方法，研究了Ag3PO4敏感材料对NH3具有特异响应性的缘由，证明表面原子与气体分子的作用机制是其气敏选择性的来源。.本项目为深入理解气敏材料气敏反应过程的物理、化学内涵，为气敏材料的性能调控提供一定理论支撑。