新型石墨烯/酞菁功能复合材料的制备及其气敏特性的研究

Graphene, a two-dimensional(2D) sp2-bonded structure, has been demonstrated as a promising gas sensing material in gas sensor area because of its unique nanostructure, large surface area, extremely high electrical conductivity, carrier mobility and outstanding physicochemical property. But slow recovery time, poor selectivity, solubility and dispersibility and the limit of film forming method may be needed to solve. It is an effective method to improve the gas sensitivity of graphene by chemical or physical functionalization. This project is to prepare novel graphene/phthalocyanine hybrids by covalent and noncovalent methods. Covalent bonding hybrids, joined by covalent bonds, can be prepared by reaction of the phthalocyanines containing specific amido, carboxy, hydroxy and sulfo substituents with functionalized graphene. Noncovalent bonding hybrids can be prepared either by the strong interactions between delocalized π-electrons of graphene and those in phthalocyanines, or by hydrogen bonding or electrostatic interactions between the specific substituents of phthalocyanine and the modified parts of the gaphene surface. The chemiresistive and MEMS gas sensor can be designed, and the gas sensing properties of hybrid films to toxic gases (NO2 and NH3) will also be studied and optimized. In combination with the theoretical calculation methods,the nature of the interaction happens among hybrid objects, the relation of material structure and performance, the interaction of materials and gas molecules, and the gas-sensing mechanism will be revealed by various characterization methods. These results are expected to be useful in obtaining novel graphene/phthalocyanine hybrids-based gas-sensing materials with high sensitivity and high selectivity, and will lay a foundation for their application in gas sensors.

由于石墨烯独特的二维纳米结构、大的比表面积、高的电导率、载流子迁移率和显著的理化性质，成为气体传感器领域最具有应用前景的气敏材料之一。但恢复时间慢、选择性差、溶解性和分散性不理想及成膜性手段受限等问题亟待解决，功能化修饰石墨烯是改善其气敏性能的有效途径。本项目拟通过具有氨基、羧基、羟基、磺酸基等活性基团的酞菁与表面功能化的石墨烯通过共价键作用，制备共价键型石墨烯/酞菁复合材料；以石墨烯与具有特定活性基团酞菁之间的π-π作用、氢键或静电力为作用力，将酞菁分子定向排列和组装在石墨烯表面上，制备非共价键型石墨烯/酞菁复合材料。设计构筑其电阻式和MEMS微气体传感器件，系统研究并优化材料对NO2和NH3等有害气体的敏感性能，结合理论计算方法，揭示石墨烯与酞菁之间相互作用本质、材料结构与性能的构效关系、材料与气体分子间作用机理，为高灵敏度、选择性新型石墨烯/酞菁复合气敏材料的开发研究提供理论依据。

本项目合成了系列四（3-异戊氧基）金属酞菁MPc(3-iso-PeO)4、四（4-异戊氧基）金属酞菁MPc(4-iso-PeO)4和四3-(4-叔丁基苯氧基)金属酞菁（TBPOMPc）配合物，通过元素分析、核磁共振、FTIR光谱和质谱等对合成产物进行了表征。利用旋涂技术制备了系列四（3-异戊氧基）金属酞菁MPc(3-iso-PeO)4、四（4-异戊氧基）金属酞菁MPc(4-iso-PeO)4薄膜，采用Uv-Vis、FTIR和AFM对配合物在薄膜中的存在状态和薄膜结构进行了分析。研究了上述配合物的电阻式传感器对NH3和NO2的气敏性，讨论了中心金属、共轭环、取代基及薄膜形貌的影响。利用非共价修饰方法制备了9种复合型还原氧化石墨烯/金属酞菁新材料，包括3种还原氧化石墨烯/四（3-异戊氧基）金属酞菁（RGO/ MPc(3-iso-PeO)4, M=Cu、Ni、Pb）复合材料、3种还原氧化石墨烯/四（4-异戊氧基）金属酞菁（RGO/ MPc(4-iso-PeO)4, M=Cu、Ni、Pb）复合材料和3种还原氧化石墨烯/四3-(4-叔丁基苯氧基)金属酞菁（RGO/TBPOMPc4, M=Cu、Ni、Pb）复合材料。利用共价修饰方法制备了4种氨基金属酞菁/氧化石墨烯复合材料（GO-4-NH2MPc），分别为GO-4-NH2CuPc，GO-4-NH2NiPc，GO-4-NH2CoPc和GO-4-NH2FePc。气敏性研究结果表明，RGO/ MPc(3-iso-PeO)4）和RGO/ MPc(4-iso-PeO)4）复合材料具有比单一RGO更优的响应恢复特性，检测极限达到750 ppb，对低浓度NH3可以实现200s内的完全恢复，响应灵敏度提高了约2-5倍；GO-4-NH2MPc复合材料具有比单一GO更好的响应恢复特性，检测极限达到12.5 ppm，对低浓度NH3可以实现100s内的完全恢复，响应灵敏度提高了约4-10倍。利用金属酞菁对石墨烯进行功能化修饰，大大改善了单一石墨烯的气敏性能，实现了两者的功能互补、协同优化，为研究和开发石墨烯基复合材料在气体传感器的应用提供了新方法和思路，展现了石墨烯/金属酞菁复合材料在气体传感领域重要的应用前景。此外，开展了金属酞菁功能化修饰碳纳米管复合材料的制备和气敏性及生物传感器研究工作，获得了一些优异的研究成果。