To validate the accuracy of the cluster model results, they were benchmarked against conventional periodic DFT results on reaction cycles (1) and (2) (Fig. ). For this comparison, the cluster model results were further refined at the B3LYP-D3/6-311G(d,p) level of theory to minimize the DFT errors as a confounding factor when comparing the cluster and slab results (see the Supporting Information for additional details). Overall, the conventional periodic DFT and the cluster model results generate similar binding energies, reaction energies, and reaction barriers.