Hybrid catalyst cascade architecture enhancement for complete ethanol electrochemical oxidation.

MWCNT-COOH, TEMPO-modified linear poly(ethylenimine), and alcohol (ADH) and aldehyde (AldDH) dehydrogenase immobilization on electrode surfaces yields a hybrid, tri-catalytic architecture that can catalyze complete ethanol electro-oxidation. The chromatographic results obtained for the tri-catalytic hybrid electrode system show that ethanol is totally oxidized to CO after 12 h of electrolysis, confirming that organic oxidation catalysts combined with enzymatic catalysts enable collection of up to 12 electrons from ethanol. The Faradaic efficiency lies above 60% for all of the electrode systems investigated herein. Overall, this study illustrates that surface-immobilized, polymer hydrogel-based hybrid multi-catalytic systems exhibit high oxidation rates and constitute a simple methodology with useful application in the development of enzymatic biofuel cells.