An Air-breathing Carbon Cloth-based Screen-printed Electrode for Applications in Enzymatic Biofuel Cells

We report a prototype air-breathing carbon cloth-based electrode that was fabricated starting from a commercially available screen-printed electrode equipped with a transparent ITO working electrode (DropSens, ref.ITO10). The fabrication of the air-breathing electrodes is straightforward, shows satisfactory reproducibility and a good electrochemical response as evaluated by means of [Fe(CN)(6)](3-/4-) voltammetry. The gas-diffusion electrodes were successfully modified with the O-2 reducing enzyme bilirubin oxidase from Myrothecium verrucaria in a direct electron transfer regime. The enzyme modified electrodes showed a remarkable high current density for O-2 reduction in passive air-breathing mode of up to 5mAcm(-2). Moreover, the enzyme modified electrodes were applied as O-2 reducing biocathodes in a glucose/air enzymatic biofuel cell in combination with a high current density glucose oxidase/redox polymer bioanode. The biofuel cell provides a high maximum power density of (0.34 +/- 0.02)mWcm(-2) at 0.25V. The straightforward design, low cost and the high reproducibility of these electrodes are considered as basis for standardized measurements under gas-breathing conditions and for high throughput screening of gas converting (bio-)catalysts.