Towards improving the catalytic activity and stability of platinum-based anodes in direct formic acid fuel cells

• A nanoparticle-based ternary catalyst was developed for the formic acid electro-oxidation (FAO).
• Pt nanoparticles, Au nanoparticles and nickel oxide nanoparticles represented the essential components of this catalyst.
• A superb enhancement in the catalytic activity of the direct FAO was achieved.
• The catalyst exhibited excellent stability extended for 7 h of continuous electrolysis.
• The deposition sequence of the catalyst ingredients has influenced greatly the catalytic enhancement.

The current investigation presents a novel catalyst for formic acid electro-oxidation (FAO); the essential anodic reaction in direct formic acid fuel cells (DFAFCs). The catalyst is developed by a sequential electrodeposition method for Pt (PtNPs), Au (AuNPs) and nickel oxide (nano-NiOx) nanoparticles onto the surface of a glassy carbon (GC) electrode. The objective of this modification was solely dedicated to the improvement of the electrode's catalytic activity by overcoming the CO poisoning, which is usually responsible for the deterioration of the catalytic performance of DFAFCs. The deposition sequence of the catalyst ingredients (PtNPs, AuNPs, and nano-NiOx) was adjusted to optimize the electrocatalytic activity and stability of the catalyst towards FAO. Interestingly, the highest catalytic activity and stability towards FAO was obtained at the NiOx/Au/Pt/GC electrode in which PtNPs were directly deposited onto the GC electrode followed by AuNPs then nano-NiOx. The discussion is oriented to adopt the role of the ternary catalyst ingredients in the catalytic enhancement.