Dependence on size of supported Rh nanoclusters for CO adsorption

Abstract

The adsorption and lateral interactions of CO molecules on Rh nanoclusters supported on an ordered thin film of Al2O3/NiAl(100) altered with the size of the Rh clusters.

Study of the Rate-Determining Step of Rh Catalyzed CO2 Reduction: Insight on the Hydrogen Assisted Molecular Dissociation

“…Despite the qualitative agreement between theory and experiments concerning the adsorption geometries, experimental values for CO adsorption energy range between 1.35 ÷ 1.45 eV [43][44][45][46][47], while our DFT PBE calculations predict a much larger adsorption energy (ca. 2 eV), in agreement with previous theoretical results [48][49][50][51]. Indeed, despite PBE properly predicts properties like Rh bonds length and electronic structures [52], it was shown that it overestimates the interaction among the Rh d-type orbitals and the 2π* level of CO, leading to an overestimation of the CO adsorption energy on rhodium surfaces [53,54].…”

Promoted activity of annealed Rh nanoclusters on thin films of Al2O3/NiAl(100) in the dehydrogenation of Methanol-d4

“…To corroborate the results, we estimated also the number of surface sites with the surface area of the Rh clusters measured with STM. The estimate, which complements the above TPD approach, 68,69 shows a consistent trend: the production of either CO m or D 2 per surface site increased on the annealed clusters, 2–6 times (Fig. S2 † ).…”

“… 44,55 The CO desorption ranged from 300 to 550 K, resembling that from Rh single crystals and clusters. 39–41,66,67 No CO (or CO m ) desorbed from the Al 2 O 3 /NiAl(100) surface, as the adsorption temperature for CO on Al 2 O 3 /NiAl(100) is below 100 K. 68 As adsorbed methanol-d 4 decomposed to CO m far below 300 K (indicated by the IRAS spectra below), CO m moved to preferred sites and desorbed as molecularly adsorbed CO. For 1.0 ML Rh clusters (mean diameter 1.7 nm) as prepared ( Fig. 3a lower), the integrated intensity of desorption of CO m (black) was about half that of molecularly adsorbed CO (grey); the fraction increased to about 75% (upper in Fig.…”

The role of nanoparticle size and ligand coverage in size focusing of colloidal metal nanoparticles

“…[1][2][3][4][5][6] For example, recent synthetic methods enabled fabrication of colloidal nanoparticles with different sizes by simply altering the reaction conditions (solvent, ligand, precursor, and synthesis temperature). [7][8][9][10][11] However, since the size distribution of the nanoparticles is oen key to their specic, desired physical and chemical properties, [12][13][14][15][16][17][18] a fundamental understanding of how to control the nucleation and growth is key to enable predictive synthesis of nanoparticles with the desired properties. To date, different models and mechanisms have been proposed to describe the nucleation and growth of colloidal nanoparticles as well as size focusing and defocusing.…”