Tailoring Electronic Structure of Copper Twin Boundaries Toward Highly Efficient Nitrogen Reduction Reaction

Electrocatalytic nitrogen reduction reaction (NRR) is a promising technique to resolve the carbon emission in energy-intensive ammonia production in industry, which, however, is hampered by the lack of efficient catalysts. Herein, by density functional theory (DFT) calculations, it was demonstrated that the twin boundary (TB) of copper could effectively relieve the N₂ activation barrier in NRR. The d orbitals overlapping mode on twin boundary edge (TBE) was quite different from that on its basal plane, where the d_xz , d_yz orbitals induced unbalanced electron occupation states in π*-p_x , p_y orbitals of the adsorbed N₂ , which could effectively activate the N≡N bond. Particularly, doping transition metals (TMs) onto Cu-TBE could further improve its NRR catalytic behavior, and the Re-Cu(111)-TBE showed the lowest limiting potential (U_L ) of -0.27 V among 25 considered TMs. Moreover, the Re-Cu(111)-TBE could effectively suppress the competing hydrogen evolution reaction even under working potentials. This work has provided a deep understanding of TB in catalysis from an electronic structure point of view, paving a way for further studies of TB into advanced utilization.