Nitrogen reduction reaction enhanced by single-atom transition metal catalysts on functionalized graphene: A first-principles study.

Ammonia production seeks alternatives to the conventional Haber-Bosch process, with nitrogen reduction reaction (NRR) emerging promising. Addressing the challenge of efficient catalysts, the functionalized graphene-based single atom catalysts (SACs) stand out. While prior studies have favored heteroatom-doped catalysts, the coordination of metal centers with nitrogen atoms remains underexplored. This work investigates transition metal (TM) SACs on nitrogen-doped graphene (N 3 G) using density functional theory (DFT) for electro-catalytic NRR. Results highlight the stability of V@N 3 G, Mo@N 3 G, W@N 3 G, with binding energies of −7.77, −5.43, and −3.89 eV, respectively. Insights into work function, d-band center, N–N bond, and IR stretching's role in N 2 activation are gained through this study. Bader charge analysis reveals electron redistribution between the support and adsorbed N 2. Employing Computational Hydrogen Electrode (CHE) method, comparative free energy diagrams for TM@N 3 G (V, Mo, W) via., enzymatic, consecutive, alternating, and distal pathways outline potential rate determining step (PDS) with and without the Implicit solvation method. Remarkably, W@N 3 G catalyst exhibits the lowest PDS in the presence of solvation energy, surpassing other catalysts. The multi-adsorption of N 2 on W@N 3 G enhances NRR process, stabilizing intermediates for efficient ammonia production. This computational study sheds light on metal center SACs on functionalized graphene support as a potential electro-catalyst for efficient and stable NRR. [Display omitted] • V, Mo, W@N 3 G show excellent stability on N-doped graphene. • Roles of work function, d-band, N–N bond, and IR in NRR elucidated. • Bader charge analysis reveals the dynamics of electron redistribution in N 2 adsorption. • Comparative free energy diagrams for TM@N 3 G highlight PDS via CHE method. • W@N 3 G exhibits lowest energy barrier with solvation, excelling among catalysts. [ABSTRACT FROM AUTHOR]