CO2 Electroreduction Performance of Phthalocyanine Sheet with Mn Dimer: A Theoretical Study

Due to the high surface ratio and dispersed metal sites, organometallic sheets provide a very special platform for catalysis. Here we investigate the CO2 electroreduction performance of expanded phthalocyanine sheets with different transition metal dimers using density functional theory. We have determined Mn dimer to be the best active center, and the reaction path CO2 → COOH* → CO* → CHO* → CH2O* → CH3O* → CH3OH is identified as the preferable one with the overpotential of 0.84 eV. Electronic structures analyses show that σ-bonding−π-backbonding mode exists when COOH* adsorbed on Mn2-Pc, which is different from the bonding mode on Mn-Pc counterpart. Our study indicates that the introduction of metal dimer in porous covalent organic frameworks provides a new strategy for the design of catalytic materials for CO2 electroreduction.