Synthesis and Characterization of Chemical Modified Carbon-Chitosan Composites Applied to Glucose Oxidase Fuel Cells

Abstract

The immobilization of glucose oxidase (GOx) using cross-linked carbon-chitosan pastes demonstrated their functionality as conductive enzymatic membranes for electrode applications in biofuel cells. Carbon-chitosan pastes showed best results when gels of 1.0% chitosan were used combined with carbonaceous materials, obtaining high mechanical resistant membranes also with high flexibility, after cured with ammonium hydroxide and cross-linked with glutaraldehyde (GA). To improve conductivity chemical modification was performed on the carbon-chitosan membranes using ferrocene derivatives. The studied methodology showed to be efficient in terms of immobilization load (ILmax = 38.7%; 620 U cm−2) and immobilization yield (IYmax = 43,5%). Bioelectrodes stability was also improved by an additional cross-linking step with GA. Anodic mediators selected from previous studies according to their enzyme affinity and co-factor regeneration rate, were also evaluated. The power delivered as a function of cell voltage was studied for this device in a mediated system using soluble and immobilized electron shuttles. Using the developed materials a power out-put of up to 32.8 μW cm−2 can be reached depending on the redox mediator used.