Unveiling metal mobility in a liquid Cu–Ga catalyst for ammonia synthesis

Abstract

The outlook for sustainable economic and ecological growth projects an ammonia economy as a key enabler to the energy transition landscape. The predominance of the Haber–Bosch process, however, as the current industrial process for producing ammonia subdues the sustainability of establishing an energy route predicated on ammonia. Here we capitalize on the inherent atomic structure of liquid metal alloys and the ability to modulate the electronic and geometric structures of liquid metal catalysts to drive the thermocatalytic synthesis of ammonia. By exploiting the mobility of the metal atoms in the liquid metal configuration and purposefully designing disordered metal catalysts, we provide insights into designing future transition metal-based catalysts that produce ammonia from gaseous nitrogen and hydrogen under mild operating conditions. The use of a molten Cu–Ga catalyst offers a dynamic metal complex with synergistic advantages that lift the activity of its constituent elements, exceeding the activity of a control Ru-based catalyst. The traditional Haber–Bosch process as well as recent alternative approaches based on photo- or electrocatalysis all rely on solid catalysts to convert nitrogen into ammonia. Here the authors disclose an effective method for the synthesis of this crucial commodity based on a Cu–Ga liquid metal catalyst instead.