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Explaining Cu@Pt Bimetallic Nanoparticles Activity Based on NO Adsorption
Author(s) -
Viñes Francesc,
Görling Andreas
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201905672
Subject(s) - bimetallic strip , adsorption , nanoparticle , materials science , density functional theory , atom (system on chip) , catalysis , copper , surface charge , chemical physics , metal , chemical engineering , nanotechnology , computational chemistry , chemistry , metallurgy , biochemistry , engineering , computer science , embedded system
Cu@Pt nanoparticles (NPs) are experimentally regarded as improved catalysts for NO x storage/reduction, with higher activities and selectivities compared with pure Pt or Cu NPs, and with inverse Pt@Cu NPs. Here, a density functional theory‐based study on such NP models with different sizes and shapes reveals that the observed enhanced stability of Cu@Pt compared with Pt@Cu NPs is due to energetic reasons. On both types of core@shell NPs, charge is transferred from Cu to Pt, strengthening the NP cohesion energy in Pt@Cu NPs, and spreading charge along the surface in Cu@Pt NPs. The negative surface Pt atoms in the latter diminish the NO bonding owing to an energetic rise of the Pt bands, as detected by the appliance of the d ‐band model, although other factors, such as atomic low coordination or the presence of an immediate subsurface Pt atom do as well. A charge density difference analysis discloses a donation/back‐donation mechanism in the NO adsorption.