Hydrogen is expected to play a significant role in the emerging energy landscape. However, it is challenging to store and transport hydrogen economically and safely. A promising approach is to store hydrogen in the form of ammonia. Ammonia is a liquid and has higher energy density than both liquid and compressed hydrogen at 700 atm per unit volume. Thus, it is easer and safer to be stored and transported. However, the industrial Haber-Bosch process for ammonia synthesis requires high pressure and high temperature, and is highly energy and carbon intensive. On the other hand, atmospheric synthesis of ammonia using electricity requires catalysts to improve the performance, but they often suffer from poor catalytic activity and stability due to the lack of effective designs and the constraints of chemical equilibrium. It is therefore imperative to develop efficient catalysts (e.g., nanostructured catalysts with complex compositions) and new synthesis methods that break the near-equilibrium thermodynamic limit via process innovations to enable highly active and durable electrified ammonia synthesis.

In this project, a programmable non-equilibrium electrified ammonia synthesis approach for efficient hydrogen storage will be developed. Studies will focus on the surface and gas-phase chemistries that occur during the non-equilibrium ammonia synthesis via multiscale modeling and advanced diagnostics. Explorations will include predictive catalyst design and controllable catalyst synthesis, and investigate the activity and stability behaviors of the catalysts under non-equilibrium operating conditions. In addition, variations will interrogate the role of the chemical equilibrium and reaction kinetics via a membrane reactor design. The proposed project will advance fundamental knowledge of dynamic catalysis and non-equilibrium materials through advanced in-situ and ex-situ diagnostics and characterization coupled with state-of-the-art multiscale modeling. The outcomes from the proposed research will include: (1) mechanistic understanding and predictive models of dynamic catalysis, non-equilibrium catalyst compositions, and the factors enabling catalyst stability under dynamic operation conditions; (2) new mechanistic understanding on the non-equilibrium ammonia synthesis reaction based on advanced laser diagnostics and multiscale modeling; (3) the development of non-equilibrium ammonia synthesis reactor integrated with novel catalysts, a multifunctional bilayer membrane, and a series of in-situ and ex-situ diagnostics tools for process optimization. The research will provide a novel non-equilibrium ammonia synthesis method using renewable electricity.