Interfacing electrocatalysis and biocatalysis with tungsten carbide: a high-performance, noble-metal-free microbial fuel cell.
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Bacteria↗
Biomedical subjects
Uwe Schröder
Publications and source records attributed to Uwe Schröder.
Challenges and constraints of using oxygen cathodes in microbial fuel cells.
The performance of oxygen reduction catalysts (platinum, pyrolyzed iron(ll) phthalocyanine (pyr-FePc) and cobalt tetramethoxyphenylporphyrin (pyr-CoTMPP)) is discussed in light of their application in microbial fuel cells. It is demonstrated that the physical and chemical environment in microbial fuel cells severely affects the thermodynamics and the kinetics of the electrocatalytic oxygen reduction. The neutral pH in combination with low buffer capacities and low ionic concentrations strongly affect the cathode performance and limit the fuel cell power output. Thus, the limiting current density in galvanodyanamic polarization experiments decreases from 1.5 mA cm(-2) to 0.6 mA cm(-2) (pH 3.3, E(cathode) = 0 V) when the buffer concentration is decreased from 500 to 50 mM. The cathode limitations are superposed by the increasing internal resistance of the MFC that substantially contributes to the decrease of power output. For example, the maximum power output of a model MFC decreased by 35%, from 2.3 to 1.5 mW, whereas the difference between the electrode potentials (deltaE = E(anode) - E(cathode)) decreased only by 10%. The increase of the catalyst load of pyr-FePc from 0.25 to 2 mg cm(-2) increased the cathodic current density from 0.4 to 0.97 mA cm(-2) (pH 7, 50 mM phosphate buffer). The increase of the load of such inexpensive catalyst thus represents a suitable means to improve the cathode performance in microbial fuel cells. Due to the low concentration of protons in MFCs in comparison to relatively high alkali cation levels (ratio C(Na+,K+)/C(H+) = 5 x E5 in pH 7, 50 mM phosphate buffer) the transfer of alkali ions through the proton exchange membrane plays a major role in the charge-balancing ion flux from the anodic into the cathodic compartment. This leads to the formation of pH gradients between the anode and the cathode compartment.
Bioelectric Energy Sources↗
Microbial fuel cells: methodology and technology.
Microbial fuel cell (MFC) research is a rapidly evolving field that lacks established terminology and methods for the analysis of system performance. This makes it difficult for researchers to compare devices on an equivalent basis. The construction and analysis of MFCs requires knowledge of different scientific and engineering fields, ranging from microbiology and electrochemistry to materials and environmental engineering. Describing MFC systems therefore involves an understanding of these different scientific and engineering principles. In this paper, we provide a review of the different materials and methods used to construct MFCs, techniques used to analyze system performance, and recommendations on what information to include in MFC studies and the most useful ways to present results.
Bacteria↗
Utilizing the green alga Chlamydomonas reinhardtii for microbial electricity generation: a living solar cell.
By employing living cells of the green alga Chlamydomonas reinhardtii, we demonstrate the possibility of direct electricity generation from microbial photosynthetic activity. The presented concept is based on an in situ oxidative depletion of hydrogen, photosynthetically produced by C. reinhardtii under sulfur-deprived conditions, by polymer-coated electrocatalytic electrodes.
Animals↗
In situ electrooxidation of photobiological hydrogen in a photobioelectrochemical fuel cell based on Rhodobacter sphaeroides.
In this paper, we present a photobiological fuel cell that utilizes the metabolic activity of living cells of Rhodobacter sphaeroides for the generation of electricity based on the in situ oxidation of photobiological hydrogen. Organic acids and alcohols contained in synthetic media as well as in fermented media of Escherichia coli K 12 served as the proton donor source for the photobiological hydrogen production by R. sphaeroides. We demonstrate thatthe photobiological hydrogen is efficiently oxidized in the microbial medium at electrocatalytic electrodes coated with a platinum-poly(3,4-ethylenedioxythiophene) (Pt-PEDOT) bilayer composite. The experimental results are discussed in terms of current and power output, substrate, and solar conversion efficiency.
Bioelectric Energy Sources↗
A generation of microbial fuel cells with current outputs boosted by more than one order of magnitude.
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Journal Article↗
Bacterial batteries.
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Bioelectric Energy Sources↗