Salt-Free Glycine Electrosynthesis via C−N Coupling Boosted by the Lattice Strain in Atomically Thin p-Block Bismuthene

Abstract Electrochemical C − N coupling using simple inorganic feedstocks offers a sustainable route to valuable organonitrogen compounds such as amino acids. Herein, we present an atomically-thin and acid-resistant p-block bismuthene (Bi-ene) derived via the reconstruction of a Bi-based metal − organic framework, where the enriched atomic misarrangement induces significant lattice strain that modulates the local electronic structure of the resultant Bi-ene, significantly boosting its electrocatalytic activity. Such defective Bi-ene exhibits an exceptional electrocatalytic performance for reductive C − N coupling in a salt-free acidic system, achieving a remarkable Faradaic efficiency (FE) of 95.7% and an ultrahigh yield rate of 1161 µmol cm⁻ ² h⁻ ¹ for NH₂OH generation via the nitrate reduction reaction (NtrRR). Further, the efficient co-reduction of HNO₃ and oxalic acid (OA) over Bi-ene simultaneously generates NH₂OH and glyoxylic acid (GX) respectively, which undergo effective C − N coupling to produce glycine with a high yield of 455.4 µmol cm⁻² h⁻¹. Moreover, the Bi-ene demonstrates stable performance for over 120 hours at an industrial-relevant current density of 200 mA cm⁻ ². Operando spectroscopy and calculations reveal that the strain in lattice-distorted Bi-ene optimizes the intermediate adsorption through modulating local electronic structure and thus enhances the efficacy for glycine electrosynthesis.