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Flexer V.,CNRS Paul Pascal Research Center | Flexer V.,University of Queensland | Brun N.,CNRS Paul Pascal Research Center | Brun N.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | And 4 more authors.
Physical Chemistry Chemical Physics | Year: 2013

Here we report the first membrane-free biofuel cell obtained using three-dimensional carbonaceous foam electrodes. We first developed a new synthetic pathway to produce a new carbonaceous foam electrode material bearing porosity both on the meso and macroporous scales. We proved that by increasing the porosity of our three-dimensional foams we could increase the current density of our modified electrodes. Then, by choosing the right combination of enzyme and mediator, and the right loading of active components, we achieved high current densities for an anodic system. Finally, we combined the improved cathode and anode to build a new membrane-free hybrid enzymatic biofuel cell consisting of a mediated anode and a mediator-free cathode. © 2013 the Owner Societies.

White R.J.,University of York | White R.J.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | Budarin V.L.,University of York | Clark J.H.,University of York
Chemistry - A European Journal | Year: 2010

Porous forms of pectin, a major industrial waste biomass polysaccharide, have been prepared by aqueous phase expansion routes (SBET> 200m2g-1; Vpore > 0.80 cm3 g -1)' It was demonstrated that the aqueous phase acidity crucially influenced the properties of the porous pectin form. Preparation route selection allows direction of material textural and morphological properties, thought to be the result of polysaccharide configuration, and methyl ester group hydrolysis, believed to alter the lowest energy accessible metastable polysaccharide state during gel recrystallisation. The resulting low density amorphous powders or moulda-ble monoliths (ρpower -0.20 g cm -3/ Pmonoii.h -0.07 gem-3) can be directly transformed by thermal carbonisation into low density mesoporous carbonaceous materials (e.g. ρ -0.27 gem-3 (Tp = 550°C)), which possess textural and nanoscale material morphology reflective of the porous pectin precursor employed. Acidic gelation promotes methyl ester groups hydrolysis of the polysaccharide structure, generating carbons with unusual interdigitated rod-like nanoscale morphology. Importantly, the materials presented herein are produced directly from the parent porous pectin material, without the need for additive catalyst (or template) to yield highly mesoporous products (e.g. V meso>0.45cm3g-1; polydispersity (PD) > 10 nm), with accessible tuneable functionally rich surfaces. Due to the high mesoporosity (>85%), materials have potential application in chromatography, heterogeneous catalysis and large molecule adsorption strategies. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

White R.J.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | Tauer K.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | Antonietti M.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | Titirici M.-M.,Max Planck Institute For Kolloid Und Grenzflaechenforschung
Journal of the American Chemical Society | Year: 2010

A facile and sustainable synthesis of hollow carbonaceous nanospheres is presented, offering a scalable and multifunctional route to the generation of useful nanocontainers, which critically possess the stability not offered by polymeric equivalents and functionality not afforded by other nanocarbons. Carbonization temperature provides a subtle but elegant mechanism to control structure and thereby hydrophobicity, nanopartitioning, and permeation between the inner and outer space. © 2010 American Chemical Society.

Fellinger T.-P.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | White R.J.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | Titirici M.-M.,Max Planck Institute For Kolloid Und Grenzflaechenforschung | Antonietti M.,Max Planck Institute For Kolloid Und Grenzflaechenforschung
Advanced Functional Materials | Year: 2012

Hierarchically structured carbon aerogels are produced in a simple, rapid, efficient, and sustainable hydrothermal approach, using only glucose as the carbon precursor. Using sodium borate (borax) as a novel complex structure directing agent nanostructured, carbon monoliths, structurally similar to the well-known sol-gel monoliths made of silica are obtained. Experimental results indicate the acetalization reaction of monosaccharides with their dehydration product hydroxymethylfurfural to be very important and inhibiting in the process of hydrothermal carbonization. Addition of borax, leads to a competitive complexation of diols, resulting in promising secondary catalytic effect with regard to carbon yield. Accordingly, it is shown that the sugar:borax ratio directs the primary carbon nanoparticle size into the sub -50 nm range, while their spinodal destabilization ultimately results in the controlled aggregation of carbonaceous particles leading to the formation of monoliths in a simple one step hydrothermal process. Post-synthesis thermal carbonization is also used to increase surface area to the medium-high range, introducing electric conductivity into the carbon monoliths. The resulting materials are promising candidates for applications in flash chromatography, for fast adsorption/purifications, and as porous conductive electrodes. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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