Engaging the Concepts\nof Bimetallicity and Mechanical\nStrain for N<sub>2</sub> Activation: A Computational Exploration

N<sub>2</sub> activation is a vital step in the process\ntoward\nNH<sub>3</sub> production. NH<sub>3</sub> synthesis has been considered\na crucial process for the production of value-added chemicals and/or\nhydrogen carriers over recent years. In this work, density functional\ntheory (ab initio) calculations are implemented for a thorough screening\nof bimetallic alloy surfaces using Fe, Ru, and Mo as the matrix (host)\nmetals and Ag, Au, Co, Cu, Fe, Mo, Ni, Pd, Pt, Rh, and Rh as heterometals\ntoward exploring the N<sub>2</sub> catalytic activation (electronic\nand chemical characteristics); the monometallic surfaces are used\nfor critical comparison in terms of their N<sub>2</sub> activation\nbehavior. In particular, adsorption geometries/energetics, density\nof states (DOS), and charge transfer are discussed. From the N<sub>2</sub> activation on the surfaces, we could precisely capture the\ntransition state of the N<sub>2</sub> dissociation reaction/step.\nThe effect of the metal alloying (geometrical and electronic factors)\nas well as the effect of applied mechanical strain, as a tuning factor\nof alloying, are both studied and thoroughly discussed. DOS studies\nrevealed that the d-band center moved toward the negative direction\nfor all late-TM-based alloys, thereby allowing the nitrogen molecule\nto adsorb weakly as compared to the early-TM surface alloys. In terms\nof the mechanical strain, for most of the alloy surfaces studied,\napart from the Mo/Fe(110) one, the N<sub>2</sub> binding energy varies\nas a linear function of the applied strain. The mechanical effect\ntrend is in agreement with the charge transfer descending order followed:\nFe/Mo(110) > Rh/Mo(110) > Au/Mo(110) > Pt/Mo(110) > Ni/Mo(110)\n> Ru/Mo(110)\n> Cu/Mo(110) > Ag/Mo(110) > Pd/Mo(110) > Au/Mo(110), pointing\nout\nthat <i>Fe-functionalized Mo(110) surface presents the highest\ncharge transfer of −2.14 |e| to the N</i><sub>2</sub> <i>molecule</i>. This study aspires to provide navigation criteria\nthrough the abundant design criteria of N<sub>2</sub> activation catalysts.