Trends in the Binding Strength of Surface Species on Nanoparticles: How Does the Adsorption Energy Scale with the Particle Size?

The binding energy of oxygen on Pd nanoparticles was measured by a direct calorimetric method as a function of the particle size. The reduced dimensionality of the Pd substrate results in two counteracting trends: an increase of the PdO binding strength due to a change of the local configuration of the adsorption site and a strong decrease of the PdO bonding due to the reduction of the cluster size.