Single Molybdenum Atom Anchored on N-Doped Carbon as a Promising Electrocatalyst for Nitrogen Reduction into Ammonia at Ambient Conditions

Ammonia (NH3) is one of the most important industrial chemicals owing to its wide applications in various fields. However, the synthesis of NH3 at ambient conditions remains a coveted goal for chemists. In this work, we study the potential of the newly synthesized single-atom catalysts, i.e., single metal atoms (Cu, Pd, Pt, and Mo) supported on N-doped carbon for N2 reduction reaction (NRR) by employing first-principles calculations. It is found that Mo1-N1C2 can catalyze NRR through the enzymatic mechanism with an ultralow overpotential of 0.24 V. Most importantly, the removal of the produced NH3 is rapid with a free-energy uphill of only 0.47 eV for the Mo1-N1C2 catalyst, which is much lower than that for ever-reported catalysts with low overpotentials and endows Mo1-N1C2 with excellent durability. The coordination effect on activity is further evaluated, showing that the experimentally realized active site, single Mo atom coordinated by one N atom and two C atoms (Mo-N1C2), possesses the highest catalytic performance. Our study offers new opportunities for advancing electrochemical conversion of N2 into NH3 at ambient conditions.