Laminar flow-based biofuel cells: Independent tailoring of the pH at the cathode and anode to enhance the activity and stability of both enzymes

Preliminary results on tailoring the composition, in particular pH, of the individual cathode and anode streams in a laminar flow-based biofuel cell to maximize the activity and stability of the respective biocatalysts used at the cathode and the anode in a microscale biofuel cell were presented. The lack of a membrane lifted the constraint of only being able to operate in acidic media. Once mass transport issues at the cathode could be resolved, improved performance could be expected by running these fuel cells in alkaline media, as both fuel oxidation and oxygen reduction kinetics are known to be better in alkaline media. The lack of a membrane and the ability to inject separate fuel and oxidant streams enabled individual tailoring of the composition of these streams. The individual anode and cathode performance of a membraneless fuel cell in which the anode is exposed to methanol in alkaline media while the cathode is exposed to an oxygen saturated acidic stream was presented. The difference in pH resulted in a very large open cell potential of 1.4 v. This is an abstract of a paper presented ACS Fuel Chemistry Meeting (Washington, DC Fall 2005).