Figure 1

Top view of the ${\mathrm{RuO}}_2(110)$ surface showing the two prominent active sites (bridge and cus). $\mathrm{Ru}=\mathrm{\text{light}}$, large spheres, $\mathrm{O}=\mathrm{\text{dark}}$, small spheres. When focusing on these two site types, the surface can be coarse-grained to the lattice model on the right, composed of alternating rows of bridge and cus sites. Atoms lying in deeper layers have been whitened in the top view for clarity.Reuse & Permissions

Figure 2

Total ${\mathrm{CO}}_2$ yield from surfaces initially prepared with varying ${\mathrm{O}}^{\mathrm{cus}}$ coverage $\theta$. In all surfaces all bridge sites are initially covered with ${\mathrm{O}}^{\mathrm{br}}$ species, and the remaining $(1-\theta )$ cus sites not covered by ${\mathrm{O}}^{\mathrm{cus}}$ are occupied by ${\mathrm{CO}}^{\mathrm{cus}}$. The ${\mathrm{CO}}_2$ yield is given relative to the one obtained for the surface with zero ${\mathrm{O}}^{\mathrm{cus}}$ coverage. Shown are the total simulated ${\mathrm{CO}}_2$ yield, as well as the contributions from the two dominant reaction mechanisms under these conditions: ${\mathrm{O}}^{\mathrm{cus}}+{\mathrm{CO}}^{\mathrm{cus}}$ and ${\mathrm{O}}^{\mathrm{br}}+{\mathrm{CO}}^{\mathrm{cus}}$. The experimental data are taken from Ref. 3.Reuse & Permissions

Figure 3

Snapshots of the surface population in the first-principles TPR kMC simulation for the surface covered initially with 1 ML ${\mathrm{O}}^{\mathrm{br}}$, 0.5 ML ${\mathrm{O}}^{\mathrm{cus}}$ and 0.5 ML ${\mathrm{CO}}^{\mathrm{cus}}$. Shown is a schematic top view of one quarter of the simulation area of $(40\times 40)$ surface sites, where the substrate bridge sites are marked by gray stripes and the cus sites by white stripes. Oxygen adatoms are drawn as lighter gray (red) circles and adsorbed CO molecules as darker gray (blue) circles. Left panel: Initial population at $T=170\mathrm{K}$, Right panel: Population at $T=400\mathrm{K}$. At this temperature, according to mean-field $>98\%$ of all initially present ${\mathrm{CO}}^{\mathrm{cus}}$ species should already have been reacted off by the low-barrier ${\mathrm{O}}^{\mathrm{cus}}+{\mathrm{CO}}^{\mathrm{cus}}$ reaction. Instead we find 40% of them to be still present, namely, essentially all those that were not initially adsorbed immediately adjacent to a ${\mathrm{O}}^{\mathrm{cus}}$ species.Reuse & Permissions