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Anodophilic biofilm catalyzes cathodic oxygen reduction
Journal article   Peer reviewed

Anodophilic biofilm catalyzes cathodic oxygen reduction

K.Y. Cheng, G. Ho and R. Cord-Ruwisch
Environmental Science & Technology, Vol.44(1), pp.518-525
2010
DOI: https://doi.org/10.1021/es9023833
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Abstract

Poor cathodic oxygen reduction and the detrimental buildup of a pH gradient between anode and cathode are the major hurdles in the development of sustainable microbial fuel cells (MFCs). This article describes and tests a concept that can help overcoming both of these limitations, by inverting the polarity of the MFC repeatedly, allowing anodic and cathodic reactions to occur alternately in the same half-cell and hence neutralizing its respective pH effects. For simplicity, we studied polarity inversion exclusively in one half-cell, maintaining its potential at -300 mV (vs Ag/AgCl) by a potentiostat. An alternating supply of acetate and dissolved oxygen to the biofilm resulted in the tested half-cell repeatedly changing from an anode to a cathode and vice versa. This repeated inversion of current direction avoided the detrimental drifting of the electrolyte pH. Control runs without current inversion ceased to produce current, as a result of anodeacidification.The presence of the anodophilic biofilm survived the intermittent oxygen exposure and could measurably facilitate the cathodic reaction by reducing the apparent oxygen overpotential. It enabled cathodic oxygen reduction at about -150 mV (vs Ag/AgCl) compared to -300 mV (vs Ag/AgCl) for the same electrode material(granulargraphite) without biofilm. Provided that a suitable cathodic potential was chosen, the presence of "anodophilic bacteria" at the cathode could enable a 5-fold increase in power output. Overall, the ability of an electrochemically active biofilm to catalyze both substrate oxidation and cathodic oxygen reduction in a single bioelectrochemical system has been documented. This property could be useful to alleviate both the cathodic oxygen reduction and the detrimental drifting of electrolyte pH in an MFC system. Further research is warranted to explore the application of such bidirectional microbial catalytic properties for sustainable MFC processes.

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UN Sustainable Development Goals (SDGs)

This output has contributed to the advancement of the following goals:

#7 Affordable and Clean Energy

Source: InCites

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54 Record Views
85 Times Cited - Web of Science

InCites Highlights

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Citation topics
3 Agriculture, Environment & Ecology
3.83 Bioengineering
3.83.1487 Microbial Fuel Cell
Web Of Science research areas
Engineering, Environmental
Environmental Sciences
ESI research areas
Environment/Ecology
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