Electrochemical Grafting of Graphene Nano Platelets with Aryl Diazonium Salts

Abstract

To vary interfacial properties, electrochemical grafting of graphene nano platelets (GNP) with 3,5-dichlorophenyl diazonium tetrafluoroborate (aryl-Cl) and 4-nitrobenzene diazonium tetrafluoroborate (aryl-NO) was realized in a potentiodynamic mode. The covalently bonded aryl layers on GNP were characterized using atomic force microscopy and X-ray photoelectron spectroscopy. Electrochemical conversion of aryl-NO into aryl-NH was conducted. The voltammetric and impedance behavior of negatively and positively charged redox probes (Fe(CN) and Ru(NH)) on three kinds of aryl layers grafted on GNP reveal that their interfacial properties are determined by the charge states of redox probes and reactive terminal groups (-Cl, -NO, -NH) in aryl layers. On aryl-Cl and aryl-NH garted GNP, selective and sensitive monitoring of positively charged lead ions as well as negatively charged nitrite and sulfite ions was achieved, respectively. Such a grafting procedure is thus a perfect way to design and control interfacial properties of graphene.

Understanding and controlling the covalent functionalisation of graphene

“…More modest potentials can be used to accelerate SET reactions, such as the diazonium chemistry, by providing higher energy electrons to accelerate aryl formation. 51 While covalent modification of graphene is typically an addition to the hexagonal 2D framework (summarised in Fig. 2c), it is possible to modify the carbon lattice itself through heteroatom substitutions (often referred to as 'heteroatom doping').…”

General overview of graphene: Production, properties and application in polymer composites

“…Ever since the graphene revolution started in 2004, a lot of interest has been generated to find methods other than mechanical exfoliation for synthesis of graphene. In recent years, some researchers have successfully used the well-known electrochemical method to exfoliate natural graphite [157][158][159][160][161].…”

A Combined Electrochemical‐Microfluidic Strategy for the Microscale‐Sized Selective Modification of Transparent Conductive Oxides

“…The coating process is initiated by a polarization of the TCO surface, followed by the immersion in a proper precursor solution. The electrochemical grafting approach offers the advantage of generating robust coatings on a large variety of conductive substrates other than TCOs, such as noble metals, conductive polymers and more recently graphene‐based electrodes . In addition, they do not alter the main electrical and optical properties of the TCO, as we have demonstrated in our previous works .…”

“…This is particularly useful when reminding that most of TCOs are based on indium, which is a rare element on earth and thus difficult to purchase. Graphene has been regarded as a good candidate to substitute indium‐based TCOs and it is also adequate for electrografting of diazonium salts derivatives: In this context therefore it will represent the next platform toward which our efforts in the validation of the here presented electrochemical‐microfluidic combined strategy for the functionalization of conductive surfaces at the microscale will be directed.…”