As candidate descriptive parameters, we collected 24 physicochemical properties characterizing the SAAs and the surface sites where CO 2 chemisorbs (Table ). These parameters are constructed considering (free-atom) properties of the elements in the alloys, the monometallic bulk systems and of the SAA surface sites. The elemental properties are Pauling electronegativity (PE), ionization potential (IP), electron affinity (EA), and s-, p-, d-, and valence-orbital radii. We define four types of candidate descriptive parameters: host, SA, surface site, and surface site + first nearest neighbors. The host and SA parameters are defined as the properties of the elements associated with hosts and SAs. Additionally, the bulk interatomic distance is included within the host's candidate parameter. The surface site and surface site + first nearest neighbors parameters are defined as the average of the elemental properties corresponding to all atoms in the site (or ensemble). In other words, if the adsorption site is composed by more than one atom, the property average of all atoms in the ensemble is the value included in the data set. Two geometrical parameters characterizing the surface sites are included: coordination number (CN) and the generalized-CN (gen-CN). By including basic candidate descriptive param-eters, we aim to derive rules capable of screening new materials efficiently, without the need of further sophisticated DFT simulations. Additional details on the SGD AI approach, the utility function, and the candidate descriptive parameters evaluation are provided in the ESI Section 3.