Interaction of coadsorbed C and O atoms on W(100) surface: Implications of CO2 on the temperature-programmed desorption profile

The authors study the adsorption and interaction of C and O atoms on the W(100) surface by performing density functional theory based calculations. Previous experimental works showed that C and O atoms exist on the surface when CO and CO2 dissociate. In this regard, the authors investigated the possibilities of forming O2 and CO2 from the coadsorbed species. Our results reveal that O2 is not stable as a molecule and will dissociate on the surface. CO2 formation on the other hand is accompanied by an activation barrier and is stable in a bent configuration. Its formation competes with CO dissociation and recombination. The authors will demonstrate through kinetic Monte Carlo simulations the implication of CO2 formation on the temperature programmed desorption profile and show that if stable and present in significant numbers, it would lead to erosion of the β2 peak. The authors therefore deduce that CO2 formation is most likely not a stable process and that CO2 formation and its subsequent decomposition are not significant in CO/W(100).