Development of Small Scale Alcohol Biofuel Cells using Enzymes as Catalyst

Abstract

The major objective of the present study is to develop small-scale alcohol fuel-based enzymatic biofuel cells (EFCs) for power generation and alcohol biosensing applications using alcohol oxidase (AOx) as anodic catalyst. One of the key approaches we propose to develop the small-scale EFCs is to exclude external pumping system from fabricating the devices. To make the idea effective, we introduce natural cellulosic materials (cotton or papers) in the device fabrications to deliver the fuel to the bioanode through passive diffusion activity. An additional important objective of the present work is to develop a biocompatible conductive ink with high aqueous stability for fabrication of the bioelectrodes, as these are vital properties of an ink to harvest stable bioelectrocatalytic function of the redox enzymes on the electrode surfaces. We studied some biopolymers and eventually identified silk-sericin and polyethylene glycol (PEG) as suitable materials for developing a graphite-based conductive ink in a ratio of 0.03:2.0:1.0 for sericin:PEG:graphite. Interestingly, sericin facilitates transformation of amorphous graphite powder to a crystalline form in PEG environment that improved the conductivity of the ink (11.2 mS.cm-1) by 5.6-folds from the ink devoid of sericin. The viscosity and shear rate values of the ink were calculated as 0.11 Pa.s and 100s-1, respectively, thermos-stability up to 100 0C, and heat of formation (and#916;Hf) -4.204 KJ/g. In addition, the ink coated over newlinepaper surface retains high aqueous stability and the reason being recognized as the enhancement of and#946; sheets content of sericin by 2.8% upon mixing it with PEG. Then we moved towards the selection of a cathodic enzyme and used laccase for the same.