Structure-property relationship of polymeric cathode binders in microbial fuel cells

Microbial fuel cells (MFC) are a promising renewable energy production technology. Air-fed MFCs use a microbe-laden anode to liberate electrons from organic compounds, and a cathode where oxygen is reduced on the surface of an inorganic electrocatalyst, such as platinum. The electrochemical reactions to reduce oxygen to water at the cathode involve the impingement of electrons, protons, and oxygen at a catalytic site. Our previous study demonstrated that the presence of sulfonate groups in polymeric binders for the cathode impeded the oxygen reduction activity of the platinum catalyst. Here, we report the effect of hydrophilic character of non-ionic polymeric binders. Increasing the hydrophilicity by increasing length of poly(ethylene oxide) (PEO) in polystyrene-b-PEO diblock copolymer catalyst binders enhanced the electrochemical response and MFC performance due to more catalyst area being exposed to the ionic buffer. Our recent progress on understanding the electrochemical environment of the cathode catalyst will be reported.