NADH Mimic-Decorated Coordination Capsules for Biomimetic Capture of NO and Electrocatalytic Reduction to NH₃

Sustainable conversion of NO offers a promising technology for artificial nitrogen cycle, but faces challenges in integrating electrocatalysis with NO capture. Herein, a biomimetic NO capture-activation-conversion strategy was firstly formulated by encapsulating N-acetylcysteine (NAC) within a nicotinamide adenine dinucleotide (NADH) mimic-containing coordination capsule, enabling efficiently NH₃ electrosynthesis. The installed NADH mimics onto the capsule interacted with the highly reactive NO-adduct generated from NAC within the microenvironment akin to the pocket of enzyme, facilitating intramolecular hydride transfer of the substrate-involving clathrate, accompanied by the formation of oxidated NAD⁺ mimics. Subsequently, the cobalt-based coordination capsule consecutively reserved e^- from cathode while donating 2e^- to the NAD⁺ mimic simultaneously for active cofactor recovered and recycle. This coordination capsule-mediated biomimetic system exhibited enzymatic kinetics following the Michaelis-Menten mechanism in the electrochemical NO reduction and realized almost 100% Faraday efficiency at potentials below -0.2 V_RHE with a substantial NH₃ yield rate of 121.6 µmol·h^-1·cm^-2 at -0.3 V_RHE, ranking among the optimal electrocatalytic NO performance ever achieved, offering an attractive avenue toward renewable electricity-driven nitrogen fixation exploiting bioinspired artificial catalyst.