Simulation of OH- and oxygen transport in the air-cathode catalyst layer of microbial fuel cells

The mass transfer of OH- and oxygen within an air-cathode is critical for the performance of microbial fuel cells (MFCs). Improving the understanding of this complex transportation mechanism could help guide the design of air-cathodes to enhance the power density of MFCs. Herein, a 2D-agglomerate model is developed to study OH- and O2 transfer, and electrochemical performance within an air-cathode MFC. The effects of key variables (binder volume fraction, and Pt/carbon mass ratio) on OH- and oxygen transport behavior have been investi-gated. Simulation results reveal that the OH- and oxygen concentrations within the catalyst layer are closely related to the catalyst layer structure. A lower volume fraction of Nafion (R) binder is beneficial to OH- and oxygen transfer, while the Pt/carbon mass ratio has complex effects on OH- and oxygen transfer and reactions. This work aims to improve our understanding of OH- and oxygen mass transfer and offers an effective approach to con-structing high-performance air-cathode MFCs.