Supported metal nanoparticles are frequently used as models of heterogeneous catalysts, with behaviour thought to be dependent on the nanoparticle size. Above a certain size it has generally been assumed that the nanoparticle behaves in the same way towards adsorbates as would a semi-infinite crystal. In this work, we examine this proposition using CO adsorption on Pd nanoparticles supported on TiO2(110) using scanning tunnelling microscopy. The results show that the CO lateral registry differs from the single crystal. This phenomenon arises from a curvature of the nanoparticle that is caused by the underlying substrate step-edges. At a CO coverage of half a monolayer, two types of CO adlayer form in addition to those observed on the native Pd(111) surface. Density functional theory calculations suggest that their formation is driven by curvature-related strain.

Support-morphology induced modification of adsorbate bonding to nanoparticles

247th National Meeting (2014)

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