Nanostructures oxy-hydroxides of iron (III) stabilized by a polymeric matrix for use in cathodes of biomimetic fuel biocélulas / Nanoestruturas de óxi-hidróxidos de ferro (III) estabilizadas em matriz polimérica para aplicação em cátodos biomiméticos de biocélulas a combustível

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

31/05/2011

RESUMO

Biofuel cells (BFCs) are electrochemical devices that converts a source fuel into an electric current in the presence of biocatalysts. In the case of enzyme BFCs, there are some limitations, such as high control of pH, denaturation of proteins at some conditions, high cost of enzymes, hard ways of bimolecular immobilization, and others. However, the development of biomimetic systems have been used in order to replace natural enzymes into synthetic systems, and it has become a reality in the BFCs state-of-art. Thus, this work aims to synthesize a new material that mimics peroxidase enzymes that are used in cathodes of BFCs, where oxy-hydroxide of iron (III) nanoparticles stabilized on polymer poly(diallyldimethylammonium chloride) (FeOOH/Fe2O3-NPs-PDAC) were obtained by co-precipitation method. It has obtained nano-needles of FeOOH/Fe2O3, with agglomeration in spherical colloids (20 nm in radius). The latter, are highly stable in PDAC matrix, as showed by the images of Transmission Electronic Microscopy (TEM) and Vibrational Spectroscopy (FTIR). We evaluated the electrochemical activity of nanostructures by cyclic voltammetry, where a quasi-reversible redox system was attributed to Fe3+/Fe2+ couple. The diffusion coefficient (D) of FeOOH/Fe2O3-NP obtained by using Stokes-Einstein and Randles-Sevcik equations were 0.9 × 10-11 m2s-1 and 1.4 × 10-11 m2s-1, respectively. The nanoparticles showed a high electrocatalytic activity towards the reduction of H2O2; besides the increase of the faradaic current of the electrochemical reaction the overpotential shifting (from -0.29 to 0.39 V) was also observed. Whereas the FeOOH/Fe2O3-NP is a biomimetic peroxidase enzyme, it was obtained the constant apparent Michaelis-Menten about 1.1 mmol L-1. Thus, the abovementioned results obtained shows that the nanoparticles of FeOOH/Fe2O3 stabilized in PDAC are promising to act as biomimetic peroxidase, opening up new pathways in order to buildup biocathodes for BFCs

ASSUNTO(S)

engenharia de materiais e metalurgica biocélulas a combustível eletrorredução de peróxido de hidrogênio biomimético bioceluls fuel electroreduction of hydrogen peroxide biomimetic

ACESSO AO ARTIGO

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