Highly Selective Electrochemical Reduction of Dinitrogen to Ammonia at Ambient Temperature and Pressure over Iron Oxide Catalysts

作者：Xiaoyang Cui, Cheng Tang, Xiaomeng Liu, Chen Wang, Wenjun Ma, Qiang Zhang · 发表于：Chemistry - A European Journal · 年份：2018 · DOI：10.1002/chem.201800535 · 被引用次数：151 · 研究领域：Ammonia Synthesis and Nitrogen Reduction、Nanomaterials for catalytic reactions、Catalytic Processes in Materials Science

Abstract The catalytic conversion of dinitrogen (N 2 ) into ammonia under ambient conditions represents one of the Holy Grails in sustainable chemistry. As a potential alternative to the Haber–Bosch process, the electrochemical reduction of N 2 to NH 3 is attractive owing to its renewability and flexibility, as well as its sustainability for producing and storing value‐added chemicals from the abundant feedstock of water and nitrogen on earth. However, owing to the kinetically complex and energetically challenging N 2 reduction reaction (NRR) process, NRR electrocatalysts with high catalytic activity and high selectivity are rare. In this contribution, as a proof‐of‐concept, we demonstrate that both the NH 3 yield and faradaic efficiency (FE) under ambient conditions can be improved by modification of the hematite nanostructure surface. Introducing more oxygen vacancies to the hematite surface renders an improved performance in NRR, which leads to an average NH 3 production rate of 0.46 μg h −1 cm −2 and an NH 3 FE of 6.04 % at −0.9 V vs. Ag/AgCl in 0.10 m KOH electrolyte. The durability of the electrochemical system was also investigated. A surprisingly high average NH 3 production rate of 1.45 μg h −1 cm −2 and a NH 3 FE of 8.28 % were achieved after the first 1 h chronoamperometry test. This is among the highest FEs reported so far for non‐precious‐metal catalysts that use a polymer‐electrolyte‐membrane cell and is much higher than the FE of precious‐metal catalysts (e.g.,...