In-situ Reduced CuN Nanocrystals Enable High-Efficiency Ammonia Synthesis and Zinc-nitrate Batteries.

Nitrate reduction reaction (NORR) involves an 8-electron transfer process and competes with the hydrogen evolution reaction process, resulting in lower yields and Faraday efficiency (FE) in the process of NH synthesis. Especially, Cu-based catalysts (Cu and Cu) have been investigated in the field of NORR due to the energy levels of d-orbital and the least unoccupied molecular orbital (LUMO) π* of nitrate's orbital. Based on the above, we synthesized a Cu-based compound containing CuN (Cu) through a simple one-step pyrolysis method, applied it to electrocatalytic NORR, and tested the performance of the Zn-NO battery. Through various characterization analyses, Cu-based catalysts (Cu) are the key active sites in reduction reactions, making CuN a potential catalyst for ammonia synthesis. The research results indicate the application of CuN catalyst in NORR shows the best NH yield of 173.7 μmol h cm with FE reaching 91.0 % at -0.3 V vs. RHE, which is much higher than that of Cu catalyst without N. In addition, the Zn-NO battery based on CuN electrode also exhibits an NH yield of 39.8 μmol h cm 63.0 % FE, and a power density of 2.7 mW cm as well as stable cycling charge-discharge stability for 5 hours. This work guides the application of CuN enhanced regulation of the active site in the electrocatalytic synthesis of NH from NORR.