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

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 (id p and iind p ) 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. id p increases with surface coverage (h) of nano-mnox with a concurrent depression of iind p . an increase in the ratio id p/m1/2 with decreasing potential scan rate (m) 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.