(481a) Renewable NH3 As Alternative Energy Fuel for Ocean Exploration

Jian Liu, Yuyan Shao, Vanda Glezakou, Robert Cavagnaro, and Li-Jung Kuo

Pacific Northwest National Laboratory, Richland, WA 99352, USA.

Wind and wave energy constitute an abundant renewable energy source readily available to the United States. However, their practical use is limited by their fluctuating power output, expensive transmission line infrastructure and complicate integration systems to the existing grid. We propose a modular energy storage solution to convert wave or tidal energy into a carbon-neutral NH₃ fuel using an electrochemical method for ocean exploration and applications at sea. Currently, state-of-art electrocatalytic conversion using precious metals favors the competing hydrogen evolution reaction leaving insufficient vacant sites (Faraday efficiency<1%) for nitrogen reduction to occur. A high surface carbon catalyst with pyridinic N derived from metal-organic frameworks is developed under the guidance from the theoretical simulation. The enhanced N₂ adsorption and dissociation and the potential ability to suppress the competitive hydrogen evolution reaction will help to make the electrochemical synthesis of NH₃ from seawater and air more viable. An economic assessment of making and using NH₃ prepared through this route as the alternative energy fuels will be discussed. The performance of the electrocatalyst will be characterized using the rotating ring disk electrode method and compared with that of the conventional electrocatalysts.