Electrocatalytic Oxidation of CO at Pt Modified with Manganese Oxide Nanorods

Abstract

CO oxidation at Pt anodes modified with manganese oxide nanorods (nano-MnO x /Pt) has been studied by cyclic and linear sweep voltammetry. Both CO adlayer stripping and oxidation of bulk CO are enhanced by nano-MnO x as compared to unmodified Pt electrodes. This is manifested by a negative shift of approximately 200 mV in the peak potential of CO adlayer stripping at the modified compared to the unmodified Pt surface. This enhancement is attributed to the catalytic mediation of manganese oxide nanorods (electrodeposited in a γ-MnOOH single crystalline phase), which supplies oxygen species at relatively low anodic potentials and thus facilitates the oxidation of CO to CO 2 . This finding sheds new light on the formic acid oxidation in the presence of MnO x , as the latter can remove CO efficiently from the Pt surface, and hence, prevents its de-activation.A polycrystalline Pt wire is the working electrode (d= 2.0 mm, sealed in a Teflon jacket leaving an exposed

Facilitated Electro-Oxidation of Formic Acid at Nickel Oxide Nanoparticles Modified Electrodes

“…Alternatively, it can be the catalytic role of nano-NiOx that facilitates the CO oxidation at a lower potential. 31,32 The ratio of the two oxidation peaks (I p d and I p ind ) reflects the preferential oxidation pathway of FA at a particular electrode. The ratio between the two oxidation peaks, I p d /I p ind is ca.…”

“…Recent reports provided arguments supporting the catalytic enhancement of CO oxidation (to CO 2 ) by manganese oxide nanostructures in similar media. 32 In this context, the following set of equations is proposed as a plausible explanation of the observed enhancing role of nano-NiOx through a reversible transformation between lower (II) and higher (III) oxidation states of Ni oxides as follows:…”