Dual activation and C-C coupling on single atom catalyst for CO_(2) photoreduction

An excellent single-atomic photocatalyst,Ti@C_(4)N_(3),is theoretically found to effectively convert CO_(2) to C_(2)H_(6) by density functional theory(DFT)calculations and non-adiabatic molecular dynamics(NAMD)simulations.The Ti@C_(4)N_(3) photocatalyst has remarkable stability both thermally,chemically,and mechanically.Electronically,it has strong absorption properties(λ=327.77 and 529.61 nm),suitable band positions,and a long photogenerated electron lifetime(τ_(e)=38.21 ps),allowing photogenerated electrons to migrate to the surface.Notably,the high-valence active site effectively activates two CO_(2) through dual activation:Under light irradiation,the weakly adsorbed CO_(2) undergoes photo-induced activation by the photoelectron of conduction band minimum(CBM);without light,the high Lewis acidity of the Ti site induces CO_(2) activation through back-donatingπ-bond.Contrast simulation results uncovered that dual activation of CO_(2) is attributed to the thermal and photonic synergy.Furthermore,two activated CO_(2) species under light easily couple to form oxalate with the barrier of 0.19 eV,and further reduced to C_(2)H_(6) with a low activation energy of 1.09 eV.