The Oxygen Reduction Reaction in Ferrofluids: Towards Membrane‐less and Spill‐less Gas Sensors. Issue 10 (30th July 2014)

• Record Type: Journal Article
• Authors: Panchompoo, Janjira; Ge, Mengchen; Zhao, Chuan; Lim, May; Aldous, Leigh
• Is Part Of: ChemPlusChem. Volume 79:Issue 10(2014:Oct.)
• Page Start: 1498
• Page End: 1506
• Publication Date: 2014-07-30
• Subjects: electroanalysis -- iron -- magnetic properties -- nanoparticles -- sensors; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201402105
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: In this study, a "membrane‐less and spill‐less" gas‐sensing device has been evaluated for the electrochemical detection of oxygen. Iron oxide magnetic nanoparticles were prepared by chemical co‐precipitation and used to prepare an aqueous ferrofluid. The iron oxide nanoparticles were subsequently stabilised and passivated with a cationic polymer, namely, poly(diallyldimethyl ammonium chloride). The resulting ferrofluid was evaluated as an electrolyte for the analytical quantification of oxygen on screen‐printed carbon electrodes. An applied magnetic field immobilised the ferrofluid electrolyte in place to result in a "membrane‐less and spill‐less" ferrofluid‐based gas sensor. The polymer poly(diallyldimethyl ammonium chloride) was found to result in an apparent enhancement in the electrocatalysis of the system towards the oxygen reduction reaction. Furthermore, as the strength of the applied magnetic field was increased, the oxygen reduction current also increased owing to the response of the polymer‐coated nanoparticles. The oxygen reduction current was linear from 0 to 100 % oxygen content. Abstract : Spill‐less droplets : An aqueous ferrofluid based upon poly(diallyldimethyl ammonium chloride)‐coated maghemite (γ‐Fe2 O3 ) iron oxide nanoparticles can be used on disposable screen‐printed electrodes to create simple membrane‐less and spill‐less gas sensors (see figure). Apparent electrocatalysis towards the oxygen reduction reaction is observed owing to the polymer; an applied magnetic field strength both immobilises the electrolyte and enhances the oxygen reduction current.