Reshape Iron Nanoparticles Using a Zinc Oxide Nanowire Array for High Efficiency and Stable Electrocatalytic Nitrogen Fixation

As a type of century-old catalyst, the use of iron-based materials runs through the Haber–Bosch process and electrochemical synthesis of ammonia because of its excellent capability, low cost, and abundant reserves. How to continuously improve its catalytic activity and stability for electrochemical nitrogen fixation has always been a goal pursued by scientific researchers. Herein, we develop a free-standing iron-based catalyst, i.e., the iron nanoparticles with zinc oxide nanowire array support (Fe/ZnO NA), which exhibits a high ammonia yield of ∼54.81 μg h–1 mgcat.–1 and a Faradaic efficiency (FE) of ∼9.56% in a 0.5 M potassium hydroxide solution, along with good reusability and durability. Its electrocatalytic ability is superior to that of commercial Fe materials and most reported Fe-based catalysts, thus showing great competitiveness. This is because the ZnO NA not only supplies stable support for the homogeneous dispersion of Fe nanoparticles but also provides a very beneficial synergy to their catalytic activity. The work renews traditional iron-based catalysts and is thus of great significance for promoting the industrialization of electrochemical ammonia synthesis.