Carbon Nanotube PtSn Nanoparticles for Enhanced Complete Biocatalytic Oxidation of Ethylene Glycol in Biofuel Cells.

We report a hybrid catalytic system containing metallic PtSn nanoparticles deposited on multiwalled carbon nanotubes (Pt 65 Sn 35 /MWCNTs), prepared by the microwave-assisted method, coupled to the enzyme oxalate oxidase (OxOx) for complete ethylene glycol (EG) electrooxidation. Pt 65 Sn 35 /MWCNTs, without OxOx, showed good electrochemical activity toward EG oxidation and all the byproducts. Pt 65 Sn 35 /MWCNTs cleaved the glyoxilic acid C-C bond, producing CO 2 and formic acid, which was further oxidized at the electrode. Concerning EG oxidation, the catalytic activity of the hybrid system (Pt 65 Sn 35 /MWCNTs+OxOx) was twice the catalytic activity of Pt 65 Sn 35 /MWCNTs. Long-term electrolysis revealed that Pt 65 Sn 35 /MWCNTs+OxOx was much more active for EG oxidation than Pt 65 Sn 35 /MWCNTs: the charge increased by 65%. The chromatographic results proved that Pt 65 Sn 35 /MWCNTs+OxOx collected all of the 10 electrons per molecule of the fuel and was able to catalyze EG oxidation to CO 2 due to the associative oxidation between the metallic nanoparticles and the enzymatic pathway. Overall, Pt 65 Sn 35 /MWCNTs+OxOx proved to be a promising system to enhance the development of enzymatic biofuel cells for further application in the bioelectrochemistry field.