Noncovalent bond-aided MCN catalysis towards carbon dioxide by metal-doped graphitic carbon nitride

With raising carbon neutrality needs, it is crucial to develop efficient catalytic materials that effectively convert atmospheric CO₂ to value-added chemicals. The well-studied MN_xC single-atom catalysts usually experienced a single-center CO₂ reduction reaction (CO₂RR). In the work, the MCN catalysts have been designed by doping Sc/Y/La/Ac into graphitic carbon nitride, in anticipation of fabricating multi-center synergistic catalysis from not only the metal center but adjacent non-metal ligand atoms as well. The CO₂RR has been systematically explored using relativistic density functional theory calculations in combination with molecular dynamics simulations. All these catalysts activated CO₂ by bending its rigid linear structure. The CO₂→M dative bond appears only in the adduct of Sc. Unexpectedly, additional two non-covalent tetrel bonds were recognized in the CO₂ adducts of Y, La and Ac. Three catalytic active sites (MCN) are rendered by catalysts, which form a planar five-membered ring with CO of CO₂. From a thermodynamic perspective, the YCN complex suggests the best catalytic potential. It has the most negative (-0.247 eV) and moderate (0.662 eV) free energy changes for CO₂ adsorption and CO desorption, respectively. Further analyses on geometric/electronic structures and chemical bonding confirm the excellent stability and electronic transfer capability of MCN catalyst in activating CO₂.