Unveiling the Synergistic Mechanism of Transition Metal-Boron Coordination in B4C12 Nanosheets for Electro-and Photocatalytic Nitrogen Fixation

Abstract

Electrocatalytic and photocatalytic nitrogen reduction (NRR) offers a sustainable pathway for green ammonia synthesis, yet efficient catalyst development remains challenging. Two-dimensional boron carbide B₄C₁₂, with its exceptional stability and tunable band structure, presents a promising substrate. This work employs first-principles calculations to design single-atom NRR electro-photocatalysts by anchoring transition metals (TM = Ti, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Hf) onto B₄C₁₂.Screening identifies V@B₄C₁₂, Mo@B₄C₁₂ , and Re@B₄C₁₂ as exceptional candidates, exhibiting ultralow limiting potentials of -0.39 V, -0.24 V, and -0.39 V, respectively. Crucially, explicit redox potential calculations confirm these systems possess ideal conduction band edges with exceptionally high photoelectron potentials, enabling spontaneous sunlight-driven ammonia production. TM atoms doping also significantly enhances visible light absorption, facilitating photocatalytic nitrogen fixation.Furthermore, these systems demonstrate excellent thermodynamic stability and high reaction selectivity, effectively suppressing the hydrogen evolution reaction (HER). Electronic structure analysis confirms that TM doping induces TM-B2C coordination, with B-TM synergy driving efficient N₂ activation. Machine learning analysis further eluciΔGdate the underlying relationships between the ΔG of key hydrogenation steps and intrinsic catalyst descriptors. This study provides valuable insights for the rational design of high-performance single-atom NRR electro-photocatalyst.