Decarbonizing nitrogen fertilizer production via the electrochemical nitrogen oxidation reaction

Abstract

Nitric acid is an important commodity chemical in agriculture and industry, yet its conventional production through the Haber-Bosch and Ostwald processes is energy and carbon-emission intensive. An electrochemical nitrogen oxidation reaction (NOR) to produce nitrates shows great potential as an environmentally friendly method of producing fertilizers under mild conditions. Progress in this field requires fundamental mechanistic understanding and establishing robust experimental methods, which is essential for the efficient design and synthesis of electrocatalysts for the NOR. We present a synergistic computational and experimental approach to exploring NOR pathways on a PtO₂ catalyst to gain mechanistic insights into the NOR. This study marks the first attempt to perform the NOR in a vapor-fed reactor designed through advanced (additive) manufacturing. The vapor-fed reactor significantly improved the N₂ mass transport to the catalyst, allowing us to report the highest rate for nitrate production to date at $3.3\mu \text{mol}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{h}}^{-1}$$3.3\mu \text{mol}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{h}}^{-1}$ at 2.01 V vs. reversible hydrogen electrode (RHE).