Computational Screening of First-Row Transition-Metal Based Alloy Catalysts-Ligand Induced N2 Reduction Reaction Selectivity

Large-scale ammonia production through sustainable strategies from naturally abundant N-2 under ambient conditions represents a major challenge from a future perspective. Ammonia is one of the promising carbon-free alternative energy carriers. The high energy required for N N bond dissociation during the Haber-Bosch process demands extreme reaction conditions. This problem could be circumvented by tuning Fe catalyst composition with the help of an induced ligand effect on the surface. In this work, we utilized density functional theory calculations on the Fe(110) surface alloyed with first-row transition-metal (TM) series (Fe-TM) to understand the catalytic activity that facilitates the electrochemical nitrogen reduction reaction (NRR). We also calculated the selectivity against the competitive hydrogen evolution reaction (HER) under electrochemical conditions. The calculated results are compared with those from earlier reports on the periodic Fe(110) and Fe(111) surfaces, and also on the (110) surface of the Fe-85 nanocluster. Surface alloying with late TMs (Co, Ni, Cu) shows an improved NRR activity, whereas the low exchange current density observed for Fe-Co indicates less HER activity among them. Considering various governing factors, Fe-based alloys with Co (Fe-Co) showed enhanced overall performance compared to the periodic surface as well as other pure iron-based structures previously reported. Therefore, the iron-alloy based structured catalysts may also provide more opportunities in the future for enhancing NRR performance via electrochemical reduction pathways.

Automated summary

This study utilized density functional theory calculations to investigate the catalytic activity of surface-alloyed Fe catalysts in electrochemical nitrogen reduction reactions. It was found that surface alloying with late transition metals (Co, Ni, Cu) can enhance NRR activity, with Fe-Co showing lower activity in HER. Fe-Co alloy exhibited improved overall performance compared to previous iron-based structures, suggesting potential for enhancing NRR performance in the future.