Temperature and pressure effects in CO titration of ensembles in PdAu(111) alloys using first principles

García-Mota, Mónica; López, Núria

doi:10.1103/physrevb.82.075411

Cited by 30 publications

(39 citation statements)

References 50 publications

(74 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This value is similar to the ΔG for the desorption of benzylaldehyde in Au@Pd(1 ML) once dispersion and entropic terms are considered (0.46 eV). Pd grown on Au has an upward shift of the Pd band by +0.30 eV32. Strain induced by Au on Pd should increase the reactivity as the Au lattice is larger than that of Pd.…”

Section: Resultsmentioning

confidence: 99%

Volcano-like Behavior of Au-Pd Core-shell Nanoparticles in the Selective Oxidation of Alcohols

Silva

Teixeira‐Neto

López

et al. 2014

Sci Rep

Self Cite

View full text Add to dashboard Cite

Gold-palladium (AuPd) nanoparticles have shown significantly enhanced activity relative to monometallic Au and Pd catalysts. Knowledge of composition and metal domain distributions is crucial to understanding activity and selectivity, but these parameters are difficult to ascertain in catalytic experiments that have primarily been devoted to equimolar nanoparticles. Here, we report AuPd nanoparticles of varying Au:Pd molar ratios that were prepared by a seed growth method. The selective oxidation of benzyl alcohol was used as a model reaction to study catalytic activity and selectivity changes that occurred after varying the composition of Pd in bimetallic catalysts. We observed a remarkable increase in catalytic conversion when using a 10:1 Au:Pd molar ratio. This composition corresponds to the amount of Pd necessary to cover the existing Au cores with a monolayer of Pd as a full-shell cluster. The key to increased catalytic activity derives from the balance between the number of active sites and the ease of product desorption. According to density functional theory calculations, both parameters are extremely sensitive to the Pd content resulting in the volcano-like activity observed.

show abstract

Section: Resultsmentioning

confidence: 99%

Volcano-like Behavior of Au-Pd Core-shell Nanoparticles in the Selective Oxidation of Alcohols

Silva

Teixeira‐Neto

López

et al. 2014

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…18 So, the reactivity and selectivity on bimetallic nanoalloy are closely related to the atomic distribution of active sites and individual properties of components. 12,[23][24][25] The experimental investigations suggested a superior reactivity of CO oxidation which is attributed to the role of contiguous Pd atoms on Pd-Au alloy catalyst, and the contiguous Pd sites are crucial to dissociate the O 2 . At low CO pressures and temperature, the isolated Pd monomer is the most stable atomic ensemble on Aubased catalysts with low Pd coverage.…”

Section: Introductionmentioning

confidence: 99%

Catalytic activity of Pd ensembles over Au(111) surface for CO oxidation: A first-principles study

Yuan

Chen

2011

The Journal of Chemical Physics

View full text Add to dashboard Cite

Employing the first-principles pseudopotential plane-wave methods and nudged-elastic-band simulations, we studied the reaction of CO oxidation on Pd-decorated Au(111) surface. We found that the contiguous Pd ensembles are required for the CO + O(2) reaction. Interestingly, Pd dimer is an active site for the two-step reaction of CO+O(2)→OOCO→CO(2)+O, and a low energy barrier (0.29 eV) is found for the formation of the intermediate metastable state (OOCO) compared to the barrier of 0.69 eV on Pd trimer. Furthermore, the residual atomic O in the CO + O(2) reaction can be removed by another CO on Pd dimer with the barrier of 0.56 eV close to the value of 0.52 eV on Pd monomer via Langmuir-Hinshelwood mechanism. The higher energy barriers (0.96 and 0.64 eV) are also found for the CO + O reaction on Pd trimers. The calculated results indicate Pd dimer is highly reactive for CO oxidation by O(2) via association mechanism on Pd-decorated Au(111) surface.

show abstract

“…[71][72][73][74][75][76] Different than Pd x Au 1Àx bimetallic nanoparticles dispersed on silica, there is no support for AuPd(100) single crystals. The low fraction of Pd in the top surface layer is not active for CO oxidation.…”

Section: Pd-aumentioning

confidence: 99%

Synthesis, catalysis, surface chemistry and structure of bimetallic nanocatalysts

2012

View full text Add to dashboard Cite

Bimetallic catalysts are one of the main categories of metal catalysts due to the tunability of electronic and geometric structures through alloying a second metal. The integration of a second metal creates a vast number of possibilities for varying the surface structure and composition of metal catalysts toward designing new catalysts. It is well acknowledged that the surface composition, atomic arrangement, and electronic state of bimetallic catalysts could be different from those before a chemical reaction or catalysis based on ex situ studies. Thanks to advances in electron-based surface analytical techniques, the surface chemistry and structure of bimetallic nanoparticles can be characterized under reaction conditions and during catalysis using ambient pressure analytical techniques including ambient pressure XPS, ambient pressure STM, X-ray absorption spectroscopy and others. These ambient pressure studies revealed various restructurings in the composition and arrangement of atoms in the surface region of catalysts under reaction conditions or during catalysis compared to that before reaction. These restructurings are driven by thermodynamic and kinetic factors. The surface energy of the constituent metals and adsorption energy of reactant molecules or dissociated species on a metal component are two main factors from the point of view of thermodynamics. Correlations between the authentic surface structure and chemistry of catalysts during catalysis and simultaneous catalytic performance were built for understanding catalytic mechanisms of bimetallic catalysts toward designing new catalysts with high activity, selectivity, and durability.

show abstract

Temperature and pressure effects in CO titration of ensembles in PdAu(111) alloys using first principles

Cited by 30 publications

References 50 publications

Volcano-like Behavior of Au-Pd Core-shell Nanoparticles in the Selective Oxidation of Alcohols

Volcano-like Behavior of Au-Pd Core-shell Nanoparticles in the Selective Oxidation of Alcohols

Catalytic activity of Pd ensembles over Au(111) surface for CO oxidation: A first-principles study

Synthesis, catalysis, surface chemistry and structure of bimetallic nanocatalysts

Contact Info

Product

Resources

About