Electrochemical Characterization of CVD-Grown Graphene for Designing Electrode/Biomolecule Interfaces

Abstract

In research on enzyme-based biofuel cells, covalent or noncovalent molecular modifications of carbon-based electrode materials are generally used as a method for immobilizing enzymes and/or mediators. However, the influence of these molecular modifications on the electrochemical properties of electrode materials has not been clarified. In this study, we present the electrochemical properties of chemical vapor deposition (CVD)-grown monolayer graphene electrodes before and after molecular modification. The electrochemical properties of graphene electrodes were evaluated by cyclic voltammetry and electrochemical impedance measurements. A covalently modified graphene electrode showed an approximately 25-fold higher charge transfer resistance than before modification. In comparison, the electrochemical properties of a noncovalently modified graphene electrode were not degraded by the modification.

Edge-dominated hydrogen evolution reactions in ultra-narrow MoS2 nanoribbon arrays

“…The Nyquist plots for both morphologies exhibit two semicircles, which indicates a combination of homogeneous charge transfer within the MoS 2 and heterogeneous charge transfer with the electrolyte. 58 By fitting the spectra to an equivalent circuit, we observe that the ratio of both types of charge transfer resistances is similar in nanoribbons, indicating efficient carrier transport toward the edges and into the electrolyte. MoS 2 flakes, on the other hand, show a threefold difference between charge transfer resistance within the electrode and charge transfer with the electrolyte.…”

Mini-Review: Recent Technologies of Electrode and System in the Enzymatic Biofuel Cell (EBFC)

“…Enzymes are placed or immobilized on the surface of support materials, and the efficient immobilization of the enzyme is challenging. There are various ways to immobilize the enzyme on the electrode surface, such as encapsulation [3], physical adsorption, entrapment in conduction polymer [29], crosslinking [30], layer-by-layer assembly [31], and covalent attachment [32], in which the enzyme can be reusable, cost-effective, and recyclable [33]. For more understanding, the reader can view the technologies of immobilization from this reference [34].…”

“…A strong interaction between support materials and enzymes is needed to strengthen the enzyme's immobilization and reduce enzyme leaching. A study from Miki et al [32] showed that the resulting covalent bond of a nitrophenyl group on the surface of a modified graphene support strengthens interaction with enzyme, which helps the DET process between the graphene support and enzyme. Meanwhile, the study from Innamuddin et al [61] modified the CNT surface by functionalizing it with polyindole and ZnO to form an interaction support with enzyme and ferritin as a mediator.…”