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 the 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.