Chemisorption of CO2 on Nickel Surfaces

Abstract

CO₂ chemisorption on the Ni(111), Ni(100), and Ni(110) surfaces was investigated at the level of density functional theory. It was found that the ability of CO₂ chemisorption is in the order of Ni(110) > Ni(100) > Ni(111). CO₂ has exothermic chemisorption on Ni(110) and endothermic chemisorption on Ni(111), while it is thermally neutral on Ni(100). It is also found that there is no significant lateral interaction between the adsorbed CO₂ at ¹/₄ monolayer (ML) coverage, while there is stronger repulsive interaction at ¹/₂ ML. On all surfaces, the chemisorbed CO₂ is partially negatively charged, indicating the enhanced electron transfer, and the stronger the electron transfer, the stronger the CO bond elongation. The bonding nature of the adsorbed CO₂ on nickel surfaces has been analyzed. The thermodynamics of CO₂ dissociative chemisorption, compared with CO and O adsorption, has been discussed, and the thermodynamic preference is in the sequence Ni(100) > Ni(111) > Ni(110).