Fig. (a) shows the adsorption energy and the C-O bond elongation values associated with the structures containing chemisorbed CO 2 . The E ads and ∆d C-O max values are in the ranges [-1.2, 0 eV] and [0.04, 0.25 Å], respectively. These wide ranges show that the surface-adsorbate adsorption energy can be largely tuned by the choice of host and SA elements, and by the structure of the adsorption site. The SAAs displaying the strongest binding with the adsorbate, i.e., the lowest E ads values, are based on the Cu host. No clear pattern can be identified among the SAAs associated with large ∆d C-O max values. Fig. (a) also shows that low E CO 2 ads translates to large C-O bond elongations in some systems, implying that these quantities might be inversely correlated. However, the systems presenting the largest C-O bond elongations (∆d C-O max > 0.18 Å) display rather high CO 2 adsorption energy (E ads > -0.30 eV). Thus, large C-O bond elongations are not necessarily correlated with low CO 2 adsorption energies. The analysis of the charge transfer from the SAAs surfaces to chemisorbed CO 2 shows no clear correlation with the adsorption energy (see ESI Section 2.3).