CO adsorption on graphite-like ZnO bilayers supported on Cu(111), Ag(111) and Au(111) surfaces

Tosoni, Sergio; Li, Cequn; Schlexer, Philomena; Pacchioni, Gianfranco

doi:10.26434/chemrxiv.5372971.v1

Cited by 3 publications

(7 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is known to produce an overestimate of the back-donation contribution from metals to CO which, in turns, is due to a too small HOMO-LUMO gap in the free CO molecule at this level of theory [44]. This problem can be overcome using hybrid functionals, where a portion of exact exchange is included in the functional [64]. Among various formulations, here we have adopted the popular and successful HSE06 hybrid functional.…”

Section: Discussionmentioning

confidence: 99%

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

et al. 2021

Self Cite

View full text Add to dashboard Cite

The nature and local environment of Au single atoms supported and stabilized on four different oxides is studied by means of DFT + U calculations using CO as probe molecule and its stretching frequency, ωe, as a fingerprint of the site where the Au atom is bound. Four oxides are considered, anatase TiO2, tetragonal ZrO2, cubic CeO2, and a perovskite LaFeO3. In this latter case a recently reported experimental study has detected a stretching mode for CO adsorbed on Au1/LaFeO3 of 2215 cm−1, with a large blue shift, ∆ω(CO) = 72 cm−1 with respect to free CO. In order to identify the Au adsorption site that can give rise to this large blue-shift we have considered five cases: (a) Au replacing a lattice cation, (Au)subM; (b) Au replacing a lattice O anion, (Au)subO; (c) Au adsorbed on the surface, (Au)ads; (d) Au bound to an extra O atom on the surface, (AuO)ads, or (e) Au bound to two extra O atoms on the surface, (AuO2)ads. It turns out that the correct reproduction of ∆ω for CO adsorbed on positively charged gold, Auδ+, is challenging for DFT. Therefore, we have performed a comparative study of Auδ+-CO molecular compounds for which ωe(CO) is known experimentally using various kinds of DFT functionals and accurate CCSD and CCSD(T) quantum chemistry methods. Also based on this comparison we propose a tentative assignment for the observed frequency of CO adsorbed on Au1/LaFeO3 single atom catalyst. Graphic Abstract

show abstract

Section: Discussionmentioning

confidence: 99%

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…This reflects the effect of the Cu(111) support on the structural and electronic properties of ZnO films due to the charge transfer from Cu support to ZnO films. [ 26 ] The binding of ZnO on Cu(111) is mainly contributed by the van der Waals forces, with ZnO and Cu(111) distance of 2.513 Å. [ 32 ]…”

Section: Resultsmentioning

confidence: 99%

“…This is due to the fact that CO is highly sensitive to the chemical and electronic environment of materials. [ 26 ] On undoped systems, CO was bound to the Zn site, while on B and Au doped ZnO and ZnO/Cu(111) films, we considered CO bound directly to dopant sites and also on Zn sites. The CO adsorption properties and complexes are reported in table 3, figures 4 and 5.…”

Section: Resultsmentioning

confidence: 99%

“…For models of freestanding ZnO bilayer films, we used (3 × 3) supercell slab of two atomic layers and for the models of ZnO/Cu(111), (3 × 3) ZnO supercell slab of two atomic layers placed on a (4 × 4) supercell of four atomic layers Cu(111). [ 26 ] These models are shown in figure 1. For the doped models, a Zn lattice ion was substituted by a B or an Au atom.…”

Section: Models and Methodsmentioning

confidence: 99%

“…[ 24,25 ] It is worth noting that while the freestanding ZnO ultrathin films exhibit flat and graphite‐like structures, ZnO ultrathin films deposited on metals are slightly strained and corrugated. [ 26 ] In addition, the effect of the metal support on improving the adsorption and catalytic properties of ZnO films has been demonstrated by a charge transfer from the metal support to adsorbed atoms (Au), clusters (Au 20 ), or molecules (NO 2 , O 2 ) by tunneling mechanism. As a consequence, the adsorbed species become negatively charged.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

B and Au dopedZnOandZnO/Cu(111) bilayer films: ADFTinvestigation

Thang,

Tram,

Thong

et al. 2022

Vietnam Journal of Chemistry

View full text Add to dashboard Cite

AbstractsThe structural and electronic properties of B and Au doped graphite‐like ZnO and ZnO/Cu(111) bilayer films have been investigated by using the DFT + U scheme including dispersion correction and compared to that of undoped materials. The differences in electronic properties of the B and Au doped ZnO and ZnO/Cu(111) films compared to undoped materials were probed by CO adsorption. The same oxidation state of B (+3) was observed for B doped ZnO and ZnO/Cu(111) bilayer films. However, an excess electron associated with B doping is delocalized over the conduction band of ZnO, while it transfers to underlying Cu support of ZnO/Cu(111). This is evidenced by a much large redshift of CO frequency on B doped ZnO versus the small redshift of CO frequency on B doped ZnO/Cu(111). At variance, the oxidation state of Au dopant was reduced from +2 (5d9) for Au doped ZnO to +1 (5d10) for Au doped ZnO/Cu(111) films. This is due to the charge transfer from Cu support to doped Au which results in the stronger binding of CO on Au doped ZnO/Cu(111) compared to ZnO bilayer films. However, a slight difference in CO frequency was found for CO bound to Au doped ZnO and ZnO/Cu(111).

show abstract

A Few Questions about Single-Atom Catalysts: When Modeling Helps

et al. 2022

Self Cite

View full text Add to dashboard Cite

Metrics & MoreArticle Recommendations CONSPECTUS: Single-atom catalysis (SAC) is a fascinating and rapidly growing field in heterogeneous catalysis. In less than 20 years, this has become one of the most widely investigated subjects by the catalytic community for various good reasons: the ability to synthesize active catalysts using a minimum amount of precious metals, the expected higher selectivity of SACs compared to assemblies of nanoparticles of variable sizes, and the fact that SACs represent a bridge between homogeneous and heterogeneous catalysis. The relative simplicity of SAC structures compared to classical heterogeneous catalysts based on supported metal nanoparticles has stimulated an intense simulation activity aimed at predicting new potential catalysts from first principles, often based on machine learning algorithms. This is a very ambitious objective and ultimately represents the final goal of every modeling activity: the possibility to provide realistic predictions of new material properties and catalytic reactivity. However, one of the main reasons that theory is useful is and remains the interpretation and analysis of experimental results, with the no less crucial goal of understanding the basic principles that determine a certain functionality or reactivity. The combination of advanced characterization techniques and theoretical calculations can provide a general conceptual framework to better understand structure−function relationships. In this Account, we will address this aspect in trying to provide answers to some fundamental questions related to the structure, stability, and activity of SACs. We will start by addressing a question that arises every time a new SAC is synthesized: where are the metal atoms? What is their coordination mode with the support? Once we have shown how to address this point, we will move on to the next fundamental question: do the single atoms stay put? How does the chemical environment of a SAC depend on the preparation or reaction conditions? Next, we will analyze the importance of a full characterization of the reaction mechanism to predict reactivity. SACs, due to their analogy to coordination compounds, can form intermediates that do not exist on the surface of metal electrodes. The formation of these intermediates can influence the kinetics of the process and must be considered in the simulation. Finally, we will briefly address a more general question: how does the catalytic activity of SACs compare with that of the corresponding supported metal nanoparticles on the one hand or homogeneous molecular complexes on the other? The final message is that to answer these questions and to take full advantage of quantum chemical modeling, the results of the calculations should be continuously verified with experimental data in a cross-fertilization that is beneficial for both sides.

show abstract

CO adsorption on graphite-like ZnO bilayers supported on Cu(111), Ag(111) and Au(111) surfaces

Cited by 3 publications

References 29 publications

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

B and Au dopedZnOandZnO/Cu(111) bilayer films: ADFTinvestigation

A Few Questions about Single-Atom Catalysts: When Modeling Helps

Contact Info

Product

Resources

About