Coverage-dependent adsorption and desorption of oxygen on Pd(100)

Abstract

Articles you may be interested inReactivity of NO over K-deposited Pd (111)

O2Activation by Metal Surfaces: Implications for Bonding and Reactivity on Heterogeneous Catalysts

“…At higher O coverages and low temperatures (below 90 K), adsorbed O 2 can be observed on Pd(100). ,, This state has a stretching frequency of 726 cm –1 , which is likely indicative of a peroxo species. DFT calculations suggest that the adsorbed O 2 lies in the hollow site …”

“…Unlike most other late transition metals, direct dissociation is possible on Pd(100) at a low beam energy (56 meV) and a low temperature (100 K), , although the process is still precursor mediated at even lower beam energies. Both DFT calculations and experimental work suggest that phonons are important in the dissociation process. , The dissociation barrier is thought to be low . Surface oxide formation is facile and has been characterized by several studies. , …”

“…The pathway for O 2 dissociation often involves both a molecularly adsorbed initial state and two separated O atoms for the final state; therefore, successful O 2 dissociation needs an ensemble of adsorption sites, which can be quite large. , Due to the generally higher reactivity of O-free ensembles, the dissociation rate and sticking probability decreases with O coverage in most cases. Experimental studies have shown this, for example, for the (vicinal ,, ) Pt(111), ,, Pt(100)-(1 × 1), , Pt(110)-(1 × 2), , Pd(111), − Pd(100), , Ir(110), Ru(0001), , Cu(111), Cu(100), Cu(110), , Ag(111), and Ag(110) surfaces. However, under certain conditions, such as low surface temperature and incident kinetic energy, prolonged lifetime of the molecular precursor states mitigates this effect.…”

Predictive Beyond-Mean-Field Rate Equations for Multisite Lattice–Gas Models of Catalytic Surface Reactions: CO Oxidation on Pd(100)

“…This two-stage process is simplified to a onestep process in our tailored modeling. On the basis of new KMC simulations, we suggest an optimum choice of ΔE TS ≈ 0.75 eV (versus ΔE TS ≈ 1.0 eV used previously 54 ), which yields a realistic saturation O coverage between 0.3 and 0.4 ML at 300 K 46,60 corresponding to that in our tailored modeling. 50 Finally, it is natural to consider extension of our analytic beyond-MF approach to more complex and realistic models.…”

Femtosecond Laser-Induced Recombinative O + O = O2 Reaction on Single Crystal Pd(100) Surface Requires Thermal Assistance

“…The interaction of atomic oxygen with transition metal is of pivotal importance for a variety of industrially and environmentally relevant processes, including the CO oxidation in the automobile exhaust catalytic converters. , In particular, the interaction of atomic oxygen with palladium (Pd) transition metal surfaces has attracted immense attention because Pd is one of the active oxidation catalysts used in the automobile catalytic converters , and the oxygen reduction reaction (ORR) . This is why, thus far, many fundamental investigations based on the surface science techniques have been carried out to explore the interaction of atomic oxygen with well-defined single crystal Pd surfaces [Pd(100), − Pd(110), − and Pd(111) , and palladium nanoparticles]. All these studies irrevocably have monitored the thermally activated recombinative desorption of molecular oxygen (O adsorbed + O adsorbed = O 2,gas ) to explore the interaction of atomic oxygen with the palladium surface.…”