(560cb) Post-Transition Metal Nanoparticles As Electrocatalysts for Nitrogen Reduction to Ammonia

As an important economical chemical, Ammonia (NH₃) has a wide variety of applications including fertilizers, carbon-free energy carriers and as a potential hydrogen-storage molecule. In nature, NH₃ can be biologically synthesized under ambient conditions by some microorganisms with the help of nitrogenase enzymes. In industry, however, NH₃ production is dominated by the Haber-Bosch process which requires high temperature (150-300 atm) and high pressure (150-300 atm). Electrochemical synthesis of NH₃ is a potential alternative to the Haber-Bosch process because of mild operating conditions and renewable electricity as energy source. As an emerging field, various electrocatalysts have been studied in recent years. However, optimal electrocatalysts with high NH₃ yield rate, Faradaic efficiency and stability have not yet been discovered and understood. As indicated by computational studies, transition metals such as Au and Pt could suffer from severe selectivity problem against the hydrogen reduction reaction (HER) while early transition metals such as Ti, bind N₂ too strongly to achieve high yield rate. Some recent studies on post-transition metals like Bi shed light on how to achieve a high performing electrocatalyst for N₂ reduction Inspired by these progresses, we conduct a series of study on the performance of post-transition metal (Bi, Sn) nanoparticles with various sizes and morphologies to understand of the catalytic behavior of these elements in NH₃ electrosynthesis and inspire design of more advanced electrocatalysts.