We also compared our descriptor space to the one more conventionally discussed in the community consisting of CO and H adsorption energies. Supplementary Fig. shows the selectivity map which reveals important differences to our map. First, as we discussed above H adsorption energy correlates much more closely with the CO adsorption energy than the PZC leading to selectivity separation lines lying on the diagonal instead of vertical and horizontal. Secondly, the H adsorption energy cannot efficiently separate the different product selectivity regions, like formate and CO, or the trend from C 1 to C 2 products.