• By considering the water-assisted shuttling mechanism, we have shown that CO formation has the lowest reaction barrier on Au and Ag (or at least that monodentate intermediates preferentially make CO). This was previously a discrepancy between simulations and experiments, as the HCOOH formation pathway seemed to be lower in energy. • By considering high coverage of mixed adsorbates, we have shown that both Ag and Au have monodentate adsorbates on the surface at CO 2 RR potentials, showing their ability to make CO from these intermediates. This was previously a discrepancy between simulations and experiments, as the bidentate, HCOOH-producing HCOO** intermediate was shown to be more stable than the *COOH intermediate.