TiC- and TiN-Supported Single-Atom Catalysts for Dramatic Improvements in CO2 Electrochemical Reduction to CH4

CO 2 electrochemical catalysis is limited by scaling relations due to a d-band theory of transition metals. As a means of breaking the scaling relation, it has recently been reported that hybridizing the d-orbitals of transition metal with p-orbitals of main group elements or using naturally hybridized materials such as metal carbides and nitrides is a promising strategy. In this Letter, by means of density functional theory calculations, we investigate the catalytic properties of TiC, TiN, and single-atom catalysts supported on them for CO 2 electrochemical reduction. In particular, we found that when single transition-metal atoms are inserted into the surface defect sites of TiC, denoted as M@d-TiC (M = Ag, Au, Co, Cu, Fe, Ir, Ni, Os, Pd, Pt, Rh, or Ru), the iridium-doped TiC (Ir@d-TiC) is found to have a remarkably low overpotential of −0.09 V, the lowest value among any catalysts rep…