The influence of thermal annealing of Pt-based thin films on electro-oxidation of formic acid

Abstract

Due to their high electrocatalytic activity, Pt-based materials are widely investigated as electrocatalysts for the electro-oxidation of small organic molecules for fuel cells technology applications, contributing to the potential reduction of fossil fuel use in the near future. In addition to methanol, formic acid has also gained increasing attention as a potential fuel for direct fuel cells due to lower toxicity, non-flammability and a lower storage cost. The electro-oxidation of formic acid on Pt-based thin films is taking place predominantly via indirect pathway, through the dehydrogenation reaction of formic acid, with the formation of CO as a poisoning species. The activity of electrocatalysts is dependent both on surface structure and surface orientation in terms of the arrangement of the atoms at the surface. Controlled heat treatment led to the rearrangement of surface atoms thus enhancing the catalytic properties. In order to investigate changes in morphology before and after thermal annealing, Pt/CrNi catalysts were characterized using an atomic force microscope (AFM). The performance of all catalysts was tested in formic acid electro-oxidation reaction. The synergistic effect of individual metallic components, in the designed catalyst, resulted in high activity and exceptional stability. The approach demonstrated in this work may promote the development of new generation of high-performance catalysts for use in direct formic acid fuel cells (DFAFCs).