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Enzymatic biofuel cells (EFCs) are bioelectronic devices that use oxidoreductase enzymes as electrocatalysts for the oxidation of an organic substrate and/or the reduction of oxygen or peroxide, finalized to direct energy conversion to electricity. Enzymes provide excellent specificity towards the substrates, avoiding, in some cases, the need of membranes and noble metals, thus realizing very compact systems suitable for miniaturization. Other advantages include high catalytic activity with low overvoltage for substrate conversion, mild operating conditions, like ambient temperature and near-neutral pH and low cost. EFCs can be utilized in a variety of applications, which need low power input and the biocompatibility of the device, including implantable or wearable biofuel cells, self-powered biosensors and, generally, portable battery-free power solutions. For enzymatic biofuel cell design, an effective immobilization of enzymes on the electrodes is an important challenge to obtain direct electron transfer without mediators, resulting in higher performance and improved long term stability. The use of conductive nanomaterials and different types of polymers as electrodes allow to achieve high specific surface, increasing the number of wired enzymes per volume unit, and facilitate the electron transfer between enzyme active site and electrode. The present paper focuses on glucose fuel cells (GFCs), a subtype of conventional EFCs able to oxidize glucose provided by a lot of metabolic processes. The designs of bioanodes are focused on the use of glucose oxidase (GOx), while biocathodes are based on laccase. The realization of a preliminary prototype on lab scale is presented based on glucose oxidase immobilized on conductive polymer, which already exhibited stability over time (several months) once immobilized through innovative techniques. Since glucose is an essential, relatively abundant and almost unlimited source of energy in living organisms, possible applications are the development of implantable GFCs as well as the exploitation of agro-industrial wastes. [ABSTRACT FROM AUTHOR]

To acquire highly efficient and cost-effective fuel cells, numerous research works have been carried out to the development low cost and excellent performance of electrocatalysts. In this paper, a solution-based electrophoretic deposition (EPD) technique for fabrication of Pt-based catalyst layers is studied. Nanographitic flake coatings used as catalyst support for sputtered platinium (Pt) were fabricated via the electrophoretic deposition (EPD) of dispersed nanographitic flakes in isopropyl alcohol. Magnesium nitrate hexahydrate (MNH) was used as an additive binder in the EPD process. Subsequently, the platinium particles were deposited by a direct sputtering on the fabricated nanographitic flake coatings. [ABSTRACT FROM AUTHOR]

Active layers of the electrocatalysts were prepared by IBAD of catalytic and activating metals onto carbon (AVCarb® Carbon Fiber Paper) and metal (Al, Ti, Ta) supports. Investigation of the composition and microstructure of layers was carried out by SEM, EPMA, EBSD, and RBS methods. The obtained catalytic layers are characterized by amorphous atomic structure. According to RBS-data the content of platinum atoms in the prepared electrocatalysts is ~2×1016 cm-2; thickness of the catalytic layers reaches ~30-100 nm. Activities of electrocatalysts in the reactions of methanol and ethanol oxidation are significantly higher than the activity of a platinum electrode. [ABSTRACT FROM AUTHOR]