Microwave-Mediated ammonia synthesis over Co2Mo3N catalysts at low pressures

The Haber-Bosch process for ammonia (NH3) synthesis is a major contributor to greenhouse gas emissions and is responsible for > 2 % of the world's energy consumption each year encouraging the need for alternative renewable-based options. This study investigates an earth-abundant ternary metal nitride (i.e., Co2Mo3N) catalyst to develop a renewable-based NH3 synthesis approach, utilizing an energy-efficient microwave-assisted route. Using a combination of spectroscopic and catalytic measurements coupled with surface analysis techniques, Co2Mo3N was evaluated as a stable and efficient NH3 synthesis catalyst. Results presented here demonstrate NH3 synthesis on Co2Mo3N at ∼420 ℃ and ambient pressure yield ∼0.7 mmolNH3.gcat-1.h−1 and up to ∼12 mmolNH3.gcat-1.h−1 at 28 bar under microwave irradiation. Co2Mo3N displayed an activation energy of ∼72 kJ.mol−1 and yielded NH3 following first-order kinetics with respect to both H2 and N2. These studies illustrate the potential of using this catalyst for a sustainable, cost-effective, and environmentally friendly approach to producing NH3.