基于石墨烯气凝胶的全固态硝酸根离子选择性电极研究

All-solid-state Nitrate-selective Electrodes Based on Graphene Aerogels

全固态离子选择性电极的结构在许多制备和应用方面具有明显优势。但由于固态界面上缺少有效的离子-电子转化导致其在电位稳定性上表现较差,无法保证各界面电势的稳定性而限制了全固态离子选择性电极的应用。因此,提出使用具有三维结构的石墨烯气凝胶(GAs)作为有效的固态转接层材料,用于调节离子载体基选择性聚合膜玻碳电极基底之间的离子-电子转化,基于这一原理制备了高性能全固态硝酸根离子选择性电极。通过透射电子显微镜表征其形貌特征;将其滴涂于玻碳电极表面形成GAs修饰电极,采用循环伏安法表征其电化学行为。在上述修饰电极表面覆上硝酸根离子选择性膜后制备新型的全固态离子选择性电极,通过电位水层测试、电位测量来表征其性能。GAs转接层的离子选择性电极对硝酸根离子展现出良好的能斯特响应和10^(-4.2)mol/L的检测下限,这为实现硝酸根离子现场即时检测提供了可能。

It is of great advantage for advanced potentiometric detection systems to develop ion-selective electrodes （ISEs） by using solid-state transducer materials. Conducting polymers are the most used solid- state transducing materials. However, their reliability is strongly related to their chemical stability and the formation of internal water films. The ISEs with the implementation of graphene as ion-to-electron transducer were reported. And it was found that the electric current for the graphene modified electrode was decreased with the decrease of thickness of the graphene transducing layer. Thus, a novel all-solidstate nitrate-selective electrode with implementation of 3D multilayer graphene aerogels （GAs） as solidcontact layer was developed. And the as-prepared GAs was characterized by transmission electron microscopy （TEM）. The GAs films as transducer materials in potentiometric all-solid-state ISEs showed better electrochemical performance in reducing graphene oxide （RGO） films due to its multilayer structure, which was demonstrated by the cyclic voltammetry （CV）. As a proof of concept, the performance of the newly developed electrode was evaluated on the basis of nitrate ions. And the hydrophobic nature of the GAs fihn was characterized via the potentiometric water layer test. The obtained results showed that graphene can significantly facilitate the ion-to-electron transducer and prevent the formation of water layer between the ion-selective membrane and the graphene layer. And the new nitrateselective electrode displayed a low detection limit of 10^-4.2 mol/L. GAs offered great promise as a reliable high-performance transducer material for solid-state ISE sensors. Furthermore, the developed electrode exhibited fast response and excellent potential stability, which made it very promising for routine analysis and application.