The direct synthesis of ammonia (NH₃) from nitrogen (N₂) and water (H₂O) under mild conditions is a promising way for energy-efficient and sustainable NH₃ production. However, thermocatalytic NH₃ synthesis from N₂ and H₂O is limited by unfavorable reaction thermodynamics, and the presence of H₂O strongly suppresses N₂ activation.

In a study published in Journal of the American Chemical Society, a research team led by Prof. DENG Dehui, Prof. HUANG Rui, and Prof. YU Liang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences achieved NH₃ synthesis directly from N₂ and H₂O under mild conditions.

Researchers introduced carbon monoxide (CO) into the reaction system to regulate the overall reaction thermodynamics. Using a bifunctional Au/α-MoC_1-x catalyst, they achieved an NH₃ production rate of 61 μmol_NH3 g_cat^-1 h^-1 at 100 °C, and 1,396 μmol_NH3 g_cat^-1 h^-1 at 320 °C, which were higher than those of other single-function catalysts.

Researchers revealed that the α-MoC_1-x phase provided active Mo sites for N₂ adsorption and H₂O dissociation, while Au^δ+ species selectively adsorbed CO, promoting the removal of surface oxygen and regenerating active Mo sites. This dual functionality enabled a continuous catalytic cycle in which N₂ was activated and hydrogenated by in situ-generated OH* species to form NH₃.

"Our study opens new avenues for energy-efficient NH₃ production using water as the hydrogen source," said Prof. DENG.