Recent progress and continuing challenges in bio-fuel cells. Part I: Enzymatic cells
ABSTRACT Recent developments in bio-fuel cell technology are reviewed. A general introduction to bio-fuel cells, including their operating principles and applications, is provided. New materials and methods for the immobilisation of enzymes and mediators on electrodes, including the use of nanostructured electrodes are considered. Fuel, mediator and enzyme materials (anode and cathode), as well as cell configurations are discussed. A detailed summary of recently developed enzymatic fuel cell systems, including performance measurements, is conveniently provided in tabular form. The current scientific and engineering challenges involved in developing practical bio-fuel cell systems are described, with particular emphasis on a fundamental understanding of the reaction environment, the performance and stability requirements, modularity and scalability. In a companion review (Part II), new developments in microbial fuel cell technologies are reviewed in the context of fuel sources, electron transfer mechanisms, anode materials and enhanced O(2) reduction.
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ABSTRACT: Multi-dimensional steady-state and dynamic models for an enzymatic fuel cell are developed. In the model system, the biocatalyst (glucose oxidase) is immobilized in a porous electrically conducting anode, while glucose and a mediator are supplied from a solution. A platinum air-breathing cathode and a Nafion membrane complete the cell unit. Detailed mass and charge balances are combined with a model for the ping-pang reaction mechanism in the anode, together with oxygen reduction in the cathode. The effects of enzyme oxidation by dissolved oxygen in the anode (a competing side reaction) are also included. The model is validated against experimental polarization and power curves, and the steady-state performance under different conditions is analyzed and discussed. The simulation results demonstrate some of the possible limitations of enzymatic fuel cells and provide insights into the spatial distributions of the reactants, potentials and current.Electrochimica Acta 12/2013; 112:386-393. DOI:10.1016/j.electacta.2013.08.044 · 4.09 Impact Factor
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ABSTRACT: Co2Al-ABTS layered double hydroxides and associated Co2Al-ABTS@graphene composite were prepared in one pot technique by in situ coprecipitation. The as-obtained materials were then fully characterized by means of Powder X-Ray Diffraction, Fourier Transformed InfraRed and Scanning Electron Microscopy confirming the intercalation of azino-bis(3-ethylbenzothiazoline-6-sulphonate) (ABTS) between the LDH layers. Their electrochemical properties, according to Cyclic Voltammetry and Electrochemical Impedance Spectroscopy data, were improved compared to Zn2Al-ABTS reference material. Co2Al-ABTS hybrid LDH was found to combine both electronic transfers: interlayer provided by the presence of ABTS and intralayer due to the Co redox species. Moreover, an improvement of electronic transfer between the LDH particles was further achieved by addition of graphene. The resulting composite assemblies were tested for the first time as oxygen bioelectrode based on bilirubin oxidase. This original approach gives rise to enhanced electroenzymatic currents (�2.5) for oxygen reduction at 0 V and pH 7.0 as regard to that obtained for the reference laccase/LDH-ABTS based bioelectrode at pH 5.5.Electrochimica Acta 01/2015; 158:113-120. DOI:10.1016/j.electacta.2015.01.132 · 4.09 Impact Factor
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ABSTRACT: Utilization of carbon nanodots (CNDs), newcomers to the world of carbonaceous nanomaterials, in the electrochemistry realm has rarely been reported so far. In this study, CNDs were used as immobilization supports and electron carriers to promote direct electron transfer (DET) reactions of glucose oxidase (GOx) and bilirubin oxidase (BOD). At the CNDs electrode entrapped with GOx, a high rate constant (ks) of 6.28 ± 0.05 s(-1) for fast DET and an apparent Michaelis-Menten constant (KM(app)) as low as 0.85 ± 0.03 mM for affinity to glucose were found. By taking advantage of its excellent direct bioelectrocatalytic performances to glucose oxidation, a DET-based biosensor for glucose detection ranging from 0 to 0.64 mM with a high sensitivity of 6.1 μA mM(-1) and a limit of detection (LOD) of 1.07 ± 0.03 μM (S/N = 3) was proposed. Additionally, the promoted DET of BOD immobilized on CNDs was also observed and effectively catalyzed the reduction of oxygen to water at the onset potential of +0.51 V (vs Ag/AgCl). On the basis of the facilitated DET of these two enzymes at CNDs electrodes, a mediator-free DET-type glucose/air enzymatic biofuel cell (BFC), in which CNDs electrodes entrapped with GOx and BOD were employed for oxidizing glucose at the bioanode and reducing oxygen at the biocathode, respectively, was successfully fabricated. The constructed BFC displayed an open-circuit voltage (OCV) as high as 0.93 V and a maximum power density of 40.8 μW cm(-2) at 0.41 V. These important features of CNDs have implied to be promising materials for immobilizing enzymes and efficient platforms for elaborating bioelectrochemical devices such as biosensors and BFCs.