A systematic study of size and shape effects in the electrooxidation of formic acid over our controlled synthesized Pd nanospheres and nanocubes as material models by using infrared spectroscopy and density functional calculations was undertaken. The bridge formate intermediate on the metal terrace was identified as the main contributor to the electrooxidation activity of formic acid, whereas linear formate with much weaker adsorption energy was unstable and could not proceed to the product. It was also demonstrated that Pd(1 0 0) cubes could stabilize two bridge formate species, and thus, they show higher electrooxidation activity than Pd spheres at comparable sizes. DRIFTing away: Various structures of adsorbed formate species on a Pd cubic nanoparticle surface are identified by diffuse reflectance infrared Fourier transform spectroscopy analysis. Their coverage and adsorption strength can affect the activity of the electrooxidation of formic acid. Pd(1 0 0) cubes are able to stabilize two bridge formate species and thus show higher electrooxidation activity than Pd spheres at comparable sizes.
- density functional calculations
- morphology control
- surface probe