Biomimetic Elastic Single-Atom Protrusions Enhance Ammonia Electrosynthesis

Electrocatalytic nitrogen (N₂) reduction reaction (eNRR) is a promising route for sustainable ammonia (NH₃) generation, but the eNRR efficiency is dramatically impeded by sluggish reaction kinetics. Herein, inspired by the dynamic extension-contraction of sea anemone tentacles in response to environmental changes, we propose a biomimetic elastic Mo single-atom protrusion on vanadium oxide support (pSA Mo/VOH) electrocatalyst featuring a symmetry-breaking Mo site and an elastic Mo-O₄ pyramid for efficient eNRR. In situ spectroscopy and theoretical calculations reveal that the protruding Mo-induced symmetry-breaking structure optimizes the d-electron filling of Mo, enhancing the back-donation to the π* antibonding orbital, effectively polarizing the N≡N bond and reducing the barrier from *N₂ to *N₂H. Notably, the elastic Mo-O₄ pyramidal structure of pSA Mo provides a dynamic Mo-O microenvironment during continuous eNRR processes. This optimizes the electronic structure of the Mo sites based on different reaction intermediates, enhancing the adsorption of various N intermediates and maintaining low barriers throughout the six-step hydrogenation process. Consequently, the elastic pSA Mo/VOH exhibits an excellent NH₃ yield rate of 50.71±1.12 μg h^-1 mg^-1 and a Faradaic efficiency of 35.38±1.03 %, outperforming most electrocatalysts.