Adsorption of CO, NO, and H2 on the PdnAu55–n Nanoclusters: A Density Functional Theory Investigation within the van der Waals D3 Corrections

Batista, Krys E. A.; Silva, Juarez L. F. Da; Piotrowski, Maurício J.

doi:10.1021/acs.jpcc.8b12219

Cited by 21 publications

(12 citation statements)

References 60 publications

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“…In our work, the adsorption of atomic hydrogen is found to stabilize at 0.8 ML coverage with adsorption energy of −0.025 eV H −1 atom. This value is higher than the calculated adsorption energies on flat gold surfaces or perfect crystal NPs, [31][32][33][34] but is fully consistent with experimental works predicting the dissociative chemisorption of H 2 on gold catalyst [10,28,[35][36][37] for temperature in the range of 298-523 K [10] providing by the way, a rational explanation of the observed structural transformations. The predicted strong hydrogen adsorption governing the structural changes is also illustrated by the drastic changes in the Au 5d-band density of states of Au atoms from both the surface and the center in configuration D' compared to bare TOh_Au 201 NP.…”

Section: Resultssupporting

confidence: 89%

Revealing Size Dependent Structural Transitions in Supported Gold Nanoparticles in Hydrogen at Atmospheric Pressure

Nassereddine

Wang

Loffreda

et al. 2021

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activity of Au NPs with size smaller than 5 nm has been often attributed to sizedependent physical features such as the fraction of surface atoms. [5][6][7] For instance, in reactions of hydrogenation, it is widely accepted that surface atoms on small particles are much more active than those on large particles since the fraction of low coordinated sites, that is, at edges and corners, which are the hydrogen activation sites, increases when size decreases. [8][9][10][11] This concept has been largely adopted for studying the reactivity of Au NPs, especially by theoreticians and surface science researchers. [12] The common practice is to consider Au nanoparticles as perfect model crystals with well-defined symmetry and static surface facets interacting with low coverage of gas molecules. However, the effect of adsorbates, which induces surface changes, is generally neglected in these studies. [13][14][15] This is a serious drawback that may prevent reliable description of the catalyst reactivity that mainly depends on the configuration of the surface. Aside from structural effects, quantum size effects are also frequently invoked to explain the exceptional activity of Au NPs. [16,17] For instance, using Density Functional Theory, Illas et al. have reported that the minimum energy pathway of O 2 dissociation for different Au NPs is chemically similar whichThe enhancement of the catalytic activity of gold nanoparticles with their decreasing size is often attributed to the increasing proportion of low-coordinated surface sites. This correlation is based on the paradigmatic picture of working gold nanoparticles as perfect crystal forms having complete and static outer surface layers whatever their size. This picture is incomplete as catalysts can dynamically change their structure according to the reaction conditions and as such changes can be eventually size-dependent. In this work, using aberration-corrected environmental electron microscopy, size-dependent crystal structure and morphological evolution in gold nanoparticles exposed to hydrogen at atmospheric pressure, with loss of the face-centered cubic crystal structure of gold for particle size below 4 nm, are revealed for the first time. Theoretical calculations highlight the role of mobile gold atoms in the observed symmetry changes and particle reshaping in the critical size regime. An unprecedented stable surface molecular structure of hydrogenated gold decorating a highly distorted core is identified. By combining atomic scale in situ observations and modeling of nanoparticle structure under relevant reaction conditions, this work provides a fundamental understanding of the size-dependent reactivity of gold nanoparticles with a precise picture of their surface at working conditions.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202104571.

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Section: Resultssupporting

confidence: 89%

Revealing Size Dependent Structural Transitions in Supported Gold Nanoparticles in Hydrogen at Atmospheric Pressure

Nassereddine

Wang

Loffreda

et al. 2021

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“…Chemical ordering parameters as a function of homoatomic and heteroatomic bond counts have been applied by other groups as a useful tool to uncover mixing trends within bimetallic systems. ,, However, these parameters usually reduce the bond counts down to a single value to find correlations with structural properties of interest, like size or composition. Instead of distilling the counts down to a single parameter, we developed a visualization of NP mixing.…”

Section: Resultsmentioning

confidence: 99%

Rapid Prediction of Bimetallic Mixing Behavior at the Nanoscale

et al. 2020

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The nanoparticle (NP) design space allows for variations in size, shape, composition, and chemical ordering. In the search for low-energy structures, this results in an extremely large search space which cannot be screened by brute force methods. In this work, we develop a genetic algorithm to predict stable bimetallic NPs of any size, shape, and metal composition. Our method predicts nanostructures in agreement with experimental trends and it captures the detailed chemical ordering of an experimental 23,196-atom FePt NP with nearly atom-by-atom accuracy. Our developed screening process is extremely fast, allowing us to generate and analyze a database of 5454 low-energy bimetallic NPs. By identifying thermodynamically stable NPs, we rationalize bimetallic mixing at the nanoscale and reveal metal-, size-, and temperature-dependent mixing behavior. Importantly, our method is applicable to any bimetallic NP size, bridging the materials gap in nanoscale simulations, and guides experimentation in the lab by elucidating stability, mixing, and detailed chemical ordering behavior of bimetallic NPs.

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“…Energetics. To inspect the nanoalloy formation is either energetically favorable or not, the mixing (or excess) energy per atom 54,55 was examined to quantify the relative energetic stability of Ni n Cu clusters by using the following formula…”

Section: Computational Methods and Theoreticalmentioning

confidence: 99%

Dressing of Cu Atom over Nickel Cluster Stimulating the Poisoning-Free CO Oxidation: An Ab Initio Study

et al. 2021

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In this work using first-principles calculations based on spin-polarized density functional theory (DFT), the role of the Cu atom in degrading the poisoning of carbon monoxide (CO) over Ni n Cu clusters is unveiled. The search has been initiated with the examination of structural, magnetic, and electronic properties of Ni n+1 and Ni n Cu clusters (1 ≤ n ≤ 12). X-ray absorption near-edge structure (XANES) spectra of Ni K-edge are computed to extract the information on the oxidation states and coordination environment of metal sites of the clusters. This study is operated with the two forms of dispersion corrections, i.e., D2 and D3, with standard DFT (with LDA and GGA functionals) for the consideration of van der Waals interactions during CO adsorption. The PBE and PBE-D3 approaches are found to be capable of yielding the experimentally observed preferential site for CO adsorption. The effect of spin-polarization on the reactivity of transition metals (TMs) toward CO adsorption is crucially assessed by the electronic reactivity descriptors such as d-band center, d-band width, and fractional filling of d-band using a spin-polarized d-band center model. The effective charge transfer from Cu to Ni atoms makes Ni atoms more efficient of charge and is attributed to the degrading adsorption of CO over Ni n Cu clusters. The Ni12Cu cluster stands out with good CO oxidation activity for the Langmuir–Hinshelwood (L–H) reaction pathway.

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Adsorption of CO, NO, and H₂ on the Pd_nAu_55–n Nanoclusters: A Density Functional Theory Investigation within the van der Waals D3 Corrections

Cited by 21 publications

References 60 publications

Revealing Size Dependent Structural Transitions in Supported Gold Nanoparticles in Hydrogen at Atmospheric Pressure

Revealing Size Dependent Structural Transitions in Supported Gold Nanoparticles in Hydrogen at Atmospheric Pressure

Rapid Prediction of Bimetallic Mixing Behavior at the Nanoscale

Dressing of Cu Atom over Nickel Cluster Stimulating the Poisoning-Free CO Oxidation: An Ab Initio Study

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