Pt-embedded in monolayer g-C3N4 as a promising single-atom electrocatalyst for ammonia synthesis

The development of advanced electrocatalysts for ambient NH3 production is increasingly attractive but severely plagued by low activity and poor selectivity. Herein, we reported first-principles results to explore the potential of transition metal (Sc- Cu, Mo, Ru, Rh, Pd, Re, Ir and Pt) atoms embedded in monolayer g-C3N4 as efficient single-atom electrocatalysts for NH3 production. We found that embedding single Pt atoms in g-C3N4 enables robust stability and good electrical conductivity and particularly results in excellent activity (with a low limiting potential of -0.24 V) at room temperature. Furthermore, the dominant N-2 adsorption over that of H atoms suggests superior NH3 selectivity. Mechanistic analyses disclosed that single Pt atoms and g-C3N4 work in concert to address the significant deviation from the nitrogen linear scaling relationships, synergistically providing highly active sites for ambient electrochemical NH3 synthesis.