Tuning Spin Polarization of Iron in Oxides to Boost Electrocatalytic Ammonia Production

The electrocatalytic nitrogen reduction reaction (NRR) for ammonia production has gained attention for its potential to reduce energy consumption and environmental impact. However, effective NRR catalysts currently rely on expensive noble metals, the development of cost-effective transition metal alternatives remains highly challenging. Iron-based catalysts are underexplored because of their inherently low reactivity. In this study, it is found that tailoring spin polarization, specifically the occupation state of electronics on d orbital in iron oxides, can highly boost NRR performance with carefully designed spin polarization. Iron in perovskite SrFeO₃ with higher spin polarization shows 79 times increase in ammonia yield compared to iron in Fe₂O₃. This improvement is accompanied with 9 times increase in charge transfer between iron and *NNH, the rate-determining step of NRR manipulating the spin polarization of transition metals can lead to efficient catalysts for electrochemical NRR, offering valuable insights for enhancing catalyst performance and enabling more sustainable ammonia production.