Chemisorption of molecular oxygen on Cu(1 0 0): a Hartree–Fock and density functional study (original) (raw)

Adsorption of atomic and molecular oxygen on Cu(1 0 0)

Catalysis Today, 2005

We have studied the initial stages of the oxidation of the Cu(100) surface using ab initio calculations. Both atomic and molecular oxygen are addressed. We show that subsurface oxygen is not energetically favourable, but gets stabilized by on-surface O. We discuss the adsorption of molecular oxygen using elbow plots, which can be used in order to qualitatively understand the measured

Adsorption and dissociation of O 2 on the Cu 2 O(1 1 1) surface: Thermochemistry, reaction barrier

The adsorption and dissociation of O 2 on the perfect and oxygen-deficient Cu 2 O(1 1 1) surface have been systematically studied using periodic density functional calculations. Different kinds of possible modes of atomic O and molecular O 2 adsorbed on the Cu 2 O(1 1 1) surface are identified: atomic O is found to prefer threefold 3Cu site on the perfect surface and O vacancy site on the deficient surface, respectively. Cu CUS is the most advantageous site with molecularly adsorbed O 2 lying flatly over singly coordinate Cu CUS –Cu CSA bridge on the perfect surface. O 2 adsorbed dissociatively on the deficient surface, which is the main dis-sociation pathway of O 2 , and a small quantity of molecularly adsorbed O 2 has been obtained. Further, possible dissociation pathways of molecularly adsorbed O 2 on the Cu 2 O(1 1 1) surface are explored, the reaction energies and relevant barriers show that a small quantity of molecularly adsorbed O 2 disso-ciation into two O atoms on the deficient surface is favorable both thermodynamically and kinetically in comparison with the dissociation of O 2 on the perfect surface. The calculated results suggest that the presence of oxygen vacancy exhibits a strong chemical reactivity towards the dissociation of O 2 and can obviously improve the catalytic activity of Cu 2 O, which is in agreement with the experimental observation.