Enhanced Activity of C2N-Supported Single Co Atom Catalyst by Single Atom Promoter.

The remarkable chemical activity of metal single-atom catalysts (SACs) lies in their unique electronic states associated with the low-coordination nature of single-atom sites. Yet, electronic state manipulation normally requires direct contact with other atoms, which inevitably changes the low-coordination environment. Herein, we found by first-principle calculations that the activity of a Co SAC for HCOOH dehydrogenation is appreciably enhanced via electronic state manipulation by a noncontact single atom promoter. A Co atom and a Sn/Ge/Pb atom are anchored in the same cavity of a graphitic C2N monolayer. Surprisingly, the nonbonded promoter makes two far splitting spin states of Co almost degenerate via charge redistribution of C2N support. Further, the high-spin Co gives a remarkably low reaction barrier comparable to Pt or Pd catalysts. Our results demonstrate that the activity of a SAC can be tuned via a noncontact promoter, casting new insights into electronic state modulation of SACs on graphene-like support.