The interaction of CO with the Ru(0001)(1×1)H surface has been studied by density functional theory (DFT) periodic calculations and molecular beam techniques. The hydrogen (1×1) phase induces an activation barrier for CO adsorption with a minimum barrier height of 25 kJ mol–1. The barrier originates from the initial repulsive interaction between the CO-4s and the Ru-d3z2-r2 orbitals. Coadsorbed H also reduces the CO adsorption energy considerably and enhances the site preference of CO. On a Ru(0001)(1×1)H surface, CO adsorbs exclusively on the atop position.
J. Chem. Phys.

Riedmüller, B., Ciobica, I. M., Papageorgopoulos, D. C., Frechard, F., Berenbak, B., Kleyn, A. W., & van Santen, R. A. (2001). CO adsorption on hydrogen saturated Ru(0001). J. Chem. Phys., 115, 5244–5251. doi:10.1063/1.1395625