| 1. |
- Shen, Fei, et al.
(author)
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Supercapacitor/biofuel cell hybrid device employing biomolecules for energy conversion and charge storage
- 2019
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In: Bioelectrochemistry. - : Elsevier BV. - 1567-5394. ; 128, s. 94-99
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Journal article (peer-reviewed)abstract
- We report on a hybrid bioelectrochemical system that integrates an energy converting part, viz. a glucose/oxygen enzymatic fuel cell, with a charge-storing component, in which the redox features of the immobilized redox protein cytochrome c (cyt c) were utilized. Bilirubin oxidase and pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) were employed as the biocatalysts for dioxygen reduction and glucose oxidation, respectively. A bi-protein PQQ-GDH/cyt c signal chain was created that facilitates electron transfer between the enzyme and the electrode surface. The assembled supercapacitor/biofuel cell hybrid biodevice displays a 15 times higher power density tested in the pulse mode compared to the performance achieved from the continuously operating regime (4.5 and 0.3 μW cm −2 , respectively) with an 80% residual activity after 50 charge/discharge pulses. This can be considered as a notable step forward in the field of glucose/oxygen membrane-free, biocompatible hybrid power sources.
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| 2. |
- Shen, Fei, et al.
(author)
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Two-dimensional graphene paper supported flexible enzymatic fuel cells
- 2019
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In: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 1:7, s. 2562-2570
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Journal article (peer-reviewed)abstract
- Application of enzymatic biofuel cells (EBFCs) in wearable or implantable biomedical devices requires flexible and biocompatible electrode materials. To this end, freestanding and low-cost graphene paper is emerging among the most promising support materials. In this work, we have exploited the potential of using graphene paper with a two-dimensional active surface (2D-GP) as a carrier for enzyme immobilization to fabricate EBFCs, representing the first case of flexible graphene papers directly used in EBFCs. The 2D-GP electrodes were prepared via the assembly of graphene oxide (GO) nanosheets into a paper-like architecture, followed by reduction to form layered and cross-linked networks with good mechanical strength, high conductivity and little dependence on the degree of mechanical bending. 2D-GP electrodes served as both a current collector and an enzyme loading substrate that can be used directly as a bioanode and biocathode. Pyrroloquinoline quinone dependent glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOx) adsorbed on the 2D-GP electrodes both retain their biocatalytic activities. Electron transfer (ET) at the bioanode required Meldola blue (MB) as an ET mediator to shuttle electrons between PQQ-GDH and the electrode, but direct electron transfer (DET) at the biocathode was achieved. The resulting glucose/oxygen EBFC displayed a notable mechanical flexibility, with a wide open circuit voltage range up to 0.665 V and a maximum power density of approximately 4 μW cm-2 both fully competitive with reported values for related EBFCs, and with mechanical flexibility and facile enzyme immobilization as novel merits.
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