Electrocatalysis by nanoparticles: Oxidation of formic acid at manganese oxide nanorods-modified Pt planar and nanohole-arrays

Journal of Advanced Research

关键词: Nanostructures;    Nanohole-arrays;    Manganese oxide nanorods;    Modified surfaces;    Electrocatalysis;   

DOI  :  10.1016/j.jare.2010.01.001

来源: DOAJ

【 摘 要 】

The electro-oxidation of formic acid (an essential reaction in direct formic acid fuel cells) is a challenging process because of the deactivation of anodes by the adsorption of the poisoning intermediate carbon monoxide (CO). Pt electrodes in two geometries (planar and nanohole-array) were modified by the electrodeposition of manganese oxide nanorods (nano-MnOx). The modified Pt electrodes were then tested for their electrocatalytic activity through the electro-oxidation of formic acid in a solution of pH 3.45. Two oxidation peaks (Ipd and Ipind) were observed at 0.2 and 0.55 V, respectively; these were assigned to the direct and indirect oxidative pathways. A significant enhancement of the direct oxidation of formic acid to CO2 was observed at the modified electrodes, while the formation of the poisoning intermediate CO was suppressed. Ipd increases with surface coverage (θ) of nano-MnOx with a concurrent depression of Ipind. An increase in the ratio Ipd/ν1/2 with decreasing potential scan rate (ν) indicates that the oxidation process proceeds via a catalytic mechanism. The modification of Pt anodes with manganese oxide nanorods results in a significant improvement of the electrocatalytic activity along with a higher tolerance to CO. Thus nano-MnOx plays a crucial role as a catalytic mediator which facilitates the charge transfer during the direct oxidation of formic acid to CO2.

【 授权许可】

Unknown