Strengthening Nitrogen Affinity on CuAu@Cu core-shell nanoparticles with Ultrathin Cu Skin via Strain Engineering and Ligand effect for Boosting Nitrogen Reduction Reaction

Abstract Although the electrochemical nitrogen reduction reaction (NRR) is regarded as a promising alternative to the Haber–Bosch process, it still suffers from the poor activity and low selectivity. Herein, we propose a powerful strategy to simultaneously boost the activity and selectivity by introducing strain engineering into the design of NRR electrocatalysts. The strain-engineered electrocatalysts consisted of monodisperse CuAu@Cu core-shell nanoparticles with controllable Cu skin via one-pot solvothermal process. Among them, electrocatalysts with about 2 layers of atomic Cu skin (CuAu@2LCS) achieve the highest NH3 yield rate (33.9 μgNH3 h−1mgcat.−1) and Faradic efficiency (24.1%) at –0.2 V vs. RHE in 0.1 M HCl. Density functional theory (DFT) calculations reveal that owing to the unique structure of bimetallic alloys with the ultra-thin Cu skins, tensile strain and favorable ligand effect work together and tune the surface electronic structure of electrocatalysts, which not only strengthen N2 affinity but also suppress the competitive HER process.