In2O3/石墨烯复合材料的界面调控及其对呼气中痕量NO2的检测研究

Rapid detection of trace NO2 in exhaled breath with high sensitivity and selectivity and is vital for diagnostics of lung inflammation. Reduced graphene oxide (RGO) is an excellent NO2-sensing material, however, its desorption speed after a sensing event is relatively slow due to gaseous molecular interactions with higher-energy binding sites (including structural defects and oxygen functional groups) on the surface of graphene. In this study, interface modulation of higher-energy binding sites in RGO using In2O3 nanomaterial is developed. The controlled morphology and –NH2 decorated surface of In2O3 as a precursor is added into GO for purpose of fixing In2O3 at higher-energy binding sites through certain affinity. The influence of In2O3 morphology, additive In2O3 amount, and preparation condition on modulating higher-energy binding sites is investigated in this case. Moreover, the relationship between interface modulation and gas-sensing performance is also explored to prove effective modulation of higher-energy binding sites is favorable for enhancing recovery speed and improve limit of detection (LOD) of NO2, and it’s a good theoretical basis for exploiting high-performance gas sensors based on graphene material.

呼气中痕量NO2的高灵敏度、高选择性的快速检测对于肺炎疾病的初步诊断具有重要的意义。还原氧化石墨烯(RGO)是一种优良的NO2气敏材料，然而，由于其高能结合位点(结构缺陷和含氧功能基团)的存在，使得NO2在其表面的脱附速度极慢。本项目采用In2O3纳米材料对RGO中的高能位点进行界面调控，拟以表面修饰-NH2的In2O3和氧化石墨烯(GO)作为前驱体，利用-NH2与高能结合位点的特异性亲和作用，来实现特定形貌In2O3在高能结合位点上的固定。研究In2O3的形貌、添加量和制备条件等因素对高能结合位点的界面调控规律，探索界面调控与气敏性能的关联机制，揭示高能结合位点的有效调控在提升石墨烯表面的NO2脱附速度和降低NO2检测限中的作用，为开发高性能的石墨烯基气体传感器奠定理论基础。

围绕特定目标气体(NO2, 三乙胺等)的高选择性、高灵敏度快速检测，研发出了以In2O3、还原氧化石墨烯、MoO3为主的气体传感器。针对检测响应度较低和恢复速率较慢等缺点，采用合理的结构设计、表面造孔、掺杂、表面贵金属修饰、脉冲加热等手段，来提升响应、进一步降低检测下限、加快恢复速率，使其更好的满足对特定环境中目标气体的高效检测的要求。其中：(1)多孔结构In2O3的制备。片层和微立方体状的In2O3传感器在较低的工作温度下(100 oC)，对NO2表现出超高的选择性，检测极限可达10ppb，而且通过脉冲加热可将传感器的恢复时间控制在3min之内。表面破损的In2O3微米管传感器在300 oC下对三乙胺(TEA)具有较高的响应(Ra/Rg=72.5对100ppm TEA)和较好的选择性，检测限可达0.1ppm；(2)制备出了一系列的酸性MoO3纳米棒及其复合物。单纯的MoO3纳米棒对TEA表现出极高的选择性和灵敏度(Ra/Rg=101.7对100 ppm TEA)，检测下限可达0.1ppm。同时，通过缺陷调控(Cr元素掺杂)和表面贵金属(Ag纳米颗粒)修饰，进一步将对TEA的响应(Ra/Rg)提高至150.3和408.6。并且，在将脉冲加热辅助下，恢复时间可控制在2min内。在项目的执行过程中，在ACS Applied Materials & Interfaces、Journal of Alloys and Compounds等国际知名期刊上发表SCI论文5篇；培养研究生2名，协助指导研究生2名。项目组成员参加本领域主要会议4次，做分组报告1次。