Unraveling electrochemical CO reduction of the single-atom transition metals supported on N-doped phosphorene

Electrocatalytic conversion of carbon monoxide (CO) sensitively depends on the activity of catalysts. Although some catalysts have been reported in previous studies, it remains a grand challenge to develop low cost but highly active electrocatalysts for CO reduction with high selectivity. Inspired by single atom metal-nitrogen-graphene catalysts, we theoretically explored the single atom metal-nitrogen-phosphorene catalysts MN3@P (P: monolayer black phosphorus, N: nitrogen atom, M = Mo, Mn, Fe, Co, Cr, Ru, Rh, Pt, Pd, V, and W) for the CO electrochemical reduction by the means of first-principle calculations. Two efficient catalysts, MoN3@P (limiting potential U-L = -0.31 V) and MnN3@P (U-L = -0.59 V) for methane (CH4) product of the CO reduction reaction, are identified for the first time. In particular, the U-L on MoN3@P is significantly less negative than that of -0.74 V for CH4 product of Carbon dioxide (CO2) reduction reaction on copper catalysts Cu(211). This remarkable low U-L originates from the unique pi bonding interaction near Fermi level between the 2p orbital of C atom in adsorbate *CO and 4d orbital of Mo atom in MoN3@P. Furthermore, MoN3@P and MnN3@P are expected to be long-term catalysts because of excellent kinetic stabilities.