Theoretical Investigation of the Size Effect on the Oxygen Adsorption Energy of Coinage Metal Nanoparticles

Abstract

This study evaluates the finite size effect on the oxygen adsorption energy of coinage metal (Cu, Ag and Au) cuboctahedral nanoparticles in the size range of 13 to 1415 atoms (0.7–3.5 nm in diameter). Trends in particle size effects are well described with single point calculations, in which the metal atoms are frozen in their bulk position and the oxygen atom is added in a location determined from periodic surface calculations. This is shown explicitly for Cu nanoparticles, for which full geometry optimization only leads to a constant offset between relaxed and unrelaxed adsorption energies that is independent of particle size. With increasing cluster size, the adsorption energy converges systematically to the limit of the (211) extended surface. The 55-atomic cluster is an outlier for all of the coinage metals and all three materials show similar behavior with respect to particle size. Graphic Abstract

Metal–Support Interactions in Heterogeneous Catalysis: DFT Calculations on the Interaction of Copper Nanoparticles with Magnesium Oxide

“…As can be seen, large variations only exist when comparing NPs of different sizes rather than one size as a function of the metal–support interaction. The size effect is similar to what has been observed in a recent study. ,,, …”

“…These large particles require a tremendous amount of computational capacity in DFT simulations, and we therefore turn to approximate models using single-point energy calculations, greatly reducing this effort. We chose the oxygen binding energy as this is a simple enough descriptor that is sensitive to the underlying electronic structure of copper 58 and is often used to estimate the activity of copper as well as other transition metals for the hydrogenation of CO 2 to methanol. 59 First, we start with the influence of magnesia on the intrinsic stability of the copper nanoparticles.…”

“…The size effect is similar to what has been observed in a recent study. 36,37,58,61 Due to the high computational cost of DFT calculations for large systems, simplified computational models of the particle− support interface have been introduced recently. These are based on nanowires (NWs) of the transition metal interacting with the support.…”

Competition between reverse water gas shift reaction and methanol synthesis from CO2: influence of copper particle size

“…This was evident from calculated adsorption energies of atomic oxygen, an important descriptor for CO 2 hydrogenation, which reached the bulk limit from 2.5 nm particles onwards. 76 We, therefore, turned our attention to another factor that is dependent on the particle size: the ratio of various surface terminations. Thus, we considered how the concentration of these surface sites varies with particle size.…”

Morphological sensitivity of silver nanoparticles to the environment

“…The adsorption energies correspond to the energetic balance between the gain due to adsorption of atomic oxygen (effective binding energy) and the loss due to gas phase dissociation of O 2 , hence giving moderate energetics and a misleading impression of mild binding. 48,49 This being said, a few studies have reported on the binding energy of atomic oxygen on silver referenced to the gas phase oxygen atom. [50][51][52] On the Ag 13 cluster, this binding energy is really large (−3.5 eV per atom).…”