Effect of Surface and Bulk Properties of Mesoporous Carbons on the Electrochemical Behavior of GOx-Nanocomposites

Abstract

Biofuel cell (BFC) electrodes are typically manufactured by combining enzymes that act as catalysts with conductive carbon nanomaterials in a form of enzyme-nanocomposite. However, a little attention has been paid to effects of the carbon nanomaterials' structural properties on the electrochemical performances of the enzyme-nanocomposites. This work aims at studying the effects of surface and bulk properties of carbon nanomaterials with different degrees of graphitization on the electrochemical performances of glucose oxidase (GOx)-nanocomposites produced by immobilizing GOx within a network of carbon nanopaticles. Two types of carbon nanomaterials were used: graphitized mesoporous carbon (GMC) and purified mesoporous carbon (PMC). Graphitization index, surface functional groups, hydrophobic properties, and rate of aggregation were measured for as-received and acid-treated GMC and PMC samples by using Raman spectrometry, X-ray photoelectron spectroscopy ( XPS), contact angle measurement, and dynamic light scattering (DLS), respectively. In addition to these physical property characterizations, the enzyme loading and electrochemical performances of the GOx-nanocomposites were studied via elemental analysis and cyclic voltammetry tests, respectively. We also fabricated BFCs using our GOx-nanocomposite materials as the enzyme anodes, and tested their performances by obtaining current-voltage (IV) plots. Our findings suggest that the electrochemical performance of GOx-nanocomposite material is determined by the combined effects of graphitization index, electrical conductivity and surface chemistry of carbon nanomaterials.

A Self-Charging Supercapacitor for a Patch-Type Glucose Sensor

“…In this work, we confirmed that the SPSC had a power density of 0.62 mW/cm 2 through glucose sensing of 11 mM glucose concentration. Studies related to glucose-based BFCs with glucose oxidase enzyme reported a lower power density as tens of μW/cm 2 in a solution similar to or higher than the glucose concentration used in this work. , Compared to the result of the recently reported high-performance BFC study that showed 3.7 mW/cm 2 power density in a 300 mM glucose solution, we verified that high power was generated by charging the supercapacitor by glucose oxidation reactions in this study. We further showed that Arduino can be used to distinguish between normal, prediabetes, and diabetes.…”

Solid Contact Ion‐selective Electrodes on Printed Circuit Board with Membrane Displacement

“…The reason is traced to the transmembrane flux of water/ions, as confirmed by the water layer test (Figure 3). Although MCB is hydrophobic in nature [22], there may still be local island or point contacts between the membrane and the conducting substrate, which act as pathways for water. This is supported by the impedance study that indicated fusion between MCB and membrane.…”

“…In this work, we report multiplexed SCISEs based on PCB with mesoporous carbon black (MCB) for transduction. MCB belongs to a special group of conductive carbon blacks, and is characterized by high surface area (150-250 m 2 /g) [21], high hydrophobicity, and possesses low amount of surface functional groups [22]. It has significantly improved stability of ISEs based on capillary tubes compared to coated wire electrode [23].…”