Density Functional Theory Studies of Earth-Abundant Late Transition Metal-Substituted Surface plus Subsurface Iron Alloys for Selective Electrocatalytic N2 Reduction

Ammonia production from the earth-abundant feedstock of N-2 is one of the most attractive fields of research. Searching for an alternative iron-based electrocatalyst for direct ammonia synthesis is a challenging process due to the harsh reaction conditions present in the traditional route of the Haber-Bosch process. In the present work using the density functional theory (DFT) calculations, we have systematically investigated the potential of late transition metal (TM = Co, Ni, and Cu) substitution on the surface, subsurface, and surface + subsurface of Fe(110) toward the nitrogen reduction reaction (NRR) and the hydrogen evolution reaction (HER). We demonstrate that a Ni-substituted surface + subsurface catalyst can favor the electrocatalytic ammonia synthesis with the maximum Faradaic efficiency by suppressing the HER compared to the previously reported catalysts for ammonia production. These findings open a way in terms of designing surface + subsurface-substituted alloy catalysts for various catalytic reactions.

Automated summary

In this study, the potential of late transition metal substitution on the surface, subsurface, and surface + subsurface of Fe(110) for nitrogen reduction reaction and hydrogen evolution reaction was systematically investigated using density functional theory calculations. It was found that a Ni-substituted surface + subsurface catalyst showed higher efficiency in ammonia production by suppressing the hydrogen evolution reaction.