The demand for ammonia has been continuously increasing due to its widespread use in several industrial sectors including agriculture, transportation, pharmaceuticals, explosives, as well as the energy sector as a promising indirect hydrogen storage medium. Therefore, the development of an efficient process for ammonia production that currently consumes two percent of the world energy supply will be a major accomplishment. Among the alternative processes, electrocatalytic NH3 production augmented with intermittent availability of wind, light or solar thermal energy without major disruption to current infrastructure can be engineered for small-scale processes that has the potential to enable on-site, sustainable, scalable, and energy-efficient ammonia production. In the high-temperature electrocatalytic production of ammonia, N2 reacts with H2O to form NH3, H2 and oxide ions at the cathode side. Oxide ions are then conducted through the solid oxide electrolyte and reach anode side where they recombine and form gaseous oxygen. In order to achieve high activity, the cathode material should possess high electrical and ionic conductivity and high selectivity towards nitrogen activation and ammonia production. Although perovskite-type oxide materials are promising cathode catalysts due to their tunable electrical and ionic conductivity, they do not provide high activity for ammonia production. Nitrides are considered promising ammonia production catalysts due to the presence of lattice nitrogen in their structure which, in presence of H2, can be converted to NH3 and nitrogen vacancies but they do not have any ionic/electrical conductivity. In the present study, novel oxide/nitride composites including perovskite oxide-metal nitride and double perovskite oxynitride cathodes that exhibit both oxygen and nitrogen ion mobility and electrical conductivity were synthesized, characterized using several ex-situ/in-situ/operando techniques and tested in a single-chamber solid oxide electrolyte cell (SOEC)-type reactor. The electrocatalytic activity experiments showed that the synergy between oxide and nitride phases significantly enhances the NH3 production rate.

High-temperature Electrocatalytic Ammonia Production: Oxide/Nitride-type novel composite cathodes

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.