(671b) Engineering Reactors for the Electrochemical Nitrogen Oxidation Reaction Via Advanced Manufacturing

By 2050, the global population is projected to reach over 9 billion people, resulting in a need to grow over 13.5 billion tons of crops. Synthetic fertilizer is responsible for almost half of the world’s current food production and will be essential to meet growing demands. Nitrates are key components in fertilizers produced by Haber-Bosch and Ostwald processes, requiring high operating temperatures and pressures. Utilizing renewable electricity to electrochemically produce nitrate, which holds the potential to mitigate up to 1Gton of CO2 emissions annually, has proven to be challenging due to the stability of the triple bond in nitrogen gas and limitations in mass transport due to reactor design.

In this work, we have developed a process for nitrate production from nitrogen at ambient conditions using advanced manufactured (AM) electrochemical reactors. Through rapid, iterative reactor design, we significantly improve the mass transport of nitrogen gas to the catalyst. Using these reactors, we studied the nitrogen oxidation reaction (NOR) across a range of pH conditions and electrolytes on metal oxide catalysts. Computational and experimental findings suggest that by engineering an electrode-electrolyte-cell configuration, we can shift selectivity of NOR over the competing oxygen evolution reaction (OER). This work represents a promising approach for achieving NOR at high current densities and selectivities for sustainable, decentralized fertilizer production.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.