Abstract Humans contribute more fixed nitrogen than can be reduced naturally. Understanding nitrogen chemistry is essential to balancing the global nitrogen cycle. An imbalanced nitrogen cycle raises levels of nitrate (NO3–) in water. Nitrate-laden water is linked to infant methemoglobinemia and ovarian cancer in humans, and to eutrophication in water reservoirs. To denitrify water, we propose using the electrocatalytic nitrate reduction reaction (NO3RR). NO3RR sustainably removes nitrate from water and generates benign or value-added products, such as NH3 or N2. However, understanding the interconversion of NO3–, NH3, and N2 and developing new catalytic materials are critical to enabling this process. In this thesis, we explore new NO3RR electrocatalysts, including metal alloys, metal sulfides, and metal oxynitrides. Chapters II–IV focus on original research, Chapter I provides an introduction to nitrate reduction, and Chapter V provides conclusions and a future outlook.
