In-Situ Electrochemical Behaviour of Biocathode Microbial Fuel Cell (MFC)

In the present work the electrochemical behaviour of microbial cells from a biocathode microbial fuel cell (MFC) functioning with wastewater was evaluated by cyclic voltammetry. In-situ electrochemical assays were performed and, under the tested experimental conditions, the biocathode medium was found to be the most efficient for the cathodic catalysed electrochemical reduction of oxygen. Different controls using sterile media and membranes covering the electrodes were performed and compared with the regular biocathode results. In the biocathode chamber, the presence of bacteria was associated with the enhanced active redox processes and with the higher electrochemical reduction of oxygen activity. The present study is a contribution to the understanding of the viability and advantages of the biocathodes use in MFC.

Electrochemical Reduction of Oxygen and Nitric Oxide on Mn-Based Perovskites with Different A-Site Cations

Four LnMnO3+δ (Ln = La, Pr, Sm, and Gd) perovskites were synthesized and characterized by powder XRD. It was shown that the perovskite lattice became more and more distorted when lowering the size of the A-site cation. The manganite-based perovskites were evaluated for the ability to electrochemically reduce oxygen and nitric oxide in the temperature range of 200 to 400°C. At the lowest temperature, the electrodes were better at reducing nitric oxide than oxygen. At higher temperatures, the activity for the reduction of oxygen and nitric oxide became similar. The activation energies for the reduction of oxygen and nitric oxide were markedly different for LaMnO3+δ and PrMnO3+δ whereas it was similar for SmMnO3+δ and GdMnO3+δ.