Role of Back‐Donation Deciphering CO ₂ Adsorption Modes on 3 d ‐Transition Metals

The development of effective and sustainable catalysts for the long‐term use of CO 2 is highly dependent on understanding how CO 2 is adsorbed and activated on catalysts, mainly based on transition metals. Since catalysis is inherently a localized phenomenon and CO 2 tends to adsorb at the metal centers due to differences in electronegativity, detailed information on the mechanisms of CO 2 capture can be obtained by studying simplified molecular models, such as transition‐metal dimers. Using such dimer models, this article addresses the importance of d ‐orbitals that facilitate the adsorption and activation of a CO 2 molecule. In addition, the influence of back‐bonding is observed, where electrons from the filled 2 π orbitals of CO 2 are donated to the vacant orbitals of metal atoms, in different adsorption configurations of CO 2 molecule. The findings elucidate a clear connection between back‐bonding and CO 2 adsorption mechanism, highlighting particular configurations that facilitate optimal activation. Through evaluation of the correlation among d ‐orbitals, back‐bonding, and CO 2 activation within transition‐metal dimers, a viable approach is presented to design efficient catalysts to capture carbon dioxide.