Three-Dimensional Carbonaceous Porous Electrodes for Efficient Biofuel Cells

VICTORIA FLEXER; BRUN, N.; BACKOV, R.; MANO, N.

Niza

Conferencia; 61st Annual Meeting of the International Society of Electrochemistry; 2010

International Society of Electrochemistry

Today, low current densities produced by biofuel cells are one of the main challenges to address to present them as a plausible alternative to primary batteries. In such context, three dimensional electrode architectures are promising since they would highly increase the reactive surface area and therefore the enzyme loading, allowing for current enhancement. However, as large enzyme loading means larger substrate consumption, electrode materials should be designed to allow both for large surface area and fast mass transport of fuel simultaneously. Based on these premises, carbonaceous electrodes with interconnected hierarchical porosity were synthesized through coating a tetrahydrofuran (THF) solution of preformed formophenolic resin into a Si(HIPE), a silica macroporous framework,[1] and were further modified to prepare both mediated and non-mediated enzyme electrodes. We will show that these electrodes are promising candidates as electrode materials for the elaboration of efficient biofuel cells and biosensors, producing higher and more stable currents than flat electrodes. The preparation protocol is simple and low cost. The mechanical strength and the synthetic route allow for the external shape and size of the electrodes to be designed on demand, which is a most important feature to incorporate these electrodes into devices. In the first example, we will show results for the modification of the carbonaceous foams with a redox hydrogel made of glucose oxidase (GOx) and an electron conducting Os-polymer. The glucose electrooxidation current was 13-fold higher than on a flat glassy carbon electrode modified with the same mass loading of bioelectrocatalyst. In a second example, the carbonaceous foams were modified with Bilirubin Oxidase (BOD). The direct electron transfer reduction signal started at 0.45V (vs Ag/AgCl) and reached 2 mA cm-2 at 0V, at pH = 7.2, 37oC, and under O2.