An additional indication that our model is an improvement to the conventional model is the comparison between Au and Ag. The previous activity volcano suggests that Au is more active by much less than an order of magnitude. From analyzing previous experimental data on Au and Ag facets, we, however found that Au facets can be up to 3 orders of magnitude more active than Ag. With our new model, we can now argue that this is mostly due to the more positive PZC of Au which leads to increased surface charge density and thus stabilization of CO 2 and thus facilitation of the rate-limiting step. The fact that CO 2 adsorption is rate-limiting on all strongly CO producing metals suggests that rather than the pH, the surface charge density might be a much more effective parameter to tune the CO production rate (cf. also Fig. showing the minor pH effect). In addition, since Au underbinds CO, the addition of a strongly CO binding metal like Pd might be moving the system into the more active region, as recently experimentally demonstrated for Au-Pd nanoparticle catalysts and depicted here by the Pd 3 Au alloy catalyst in Fig. .