Asymmetric Coordination of Single-Atom Co Sites Achieves Efficient Dehydrogenation Catalysis

Tuning asymmetric coordination of metal single-atom (SA) sites can provide a new opportunity for optimizing the electronic structure of catalysts to achieve efficient catalysis, however, achieving such controllable design remains a grand challenge. Herein, an asymmetrically coordinated Co-N₄P SA site as a new catalyst system for achieving superior dehydrogenation catalysis of formic acid (HCOOH) is reported. The experimental results show that the Co atom is coordinated by four N atoms and one asymmetric P atom, forming the unique Co-N₄P SA sites. The Co-N₄P SA sites exhibit an impressive mass activity of 4285.6 mmol g^–1 h^–1 with 100% selectivity and outstanding stability for HCOOH dehydrogenation catalysis at 80 °C, which is 5.0, 25.5, and 23.1 times that of symmetrically coordinated Co-N₄ SA sites, commercial Pd/C and Pt/C, respectively. The in situ ATR-IR analysis demonstrates the mono-molecular H₂ produced mechanism over Co-N₄P SA sites, and theoretical calculations further reveal that the asymmetric P sites not only can boost the C-H bond cleavage of HCOO* by largely reducing the energy barrier but also facilitate the proton adsorption to achieve the fast generation of H₂ in Co-N₄P SA sites. This study opens a new way for rationally designing novel SA sites to achieve efficient catalysis.