Spin‐Selective Anti‐Perovskite Enables Breakthrough Nitrate‐to‐Ammonia Electrocatalysis

Electrochemical nitrate reduction to ammonia offers environmental and energy benefits, but progress is hindered by sluggish multistep proton-coupled electron transfers and competing side reactions. Here, we introduce an antiperovskite CuNCo₃ catalyst featuring a 3d-3d interaction framework. This framework stabilizes spin-selective Co sites even upon surface Co-N bond cleavage and drives asymmetric nitrate consumption. CuNCo₃ achieves 100% Faradaic efficiency and an NH₃ production rate of 124.6 mg mg_cat ^-1 h^-1 at -0.4 V vs. RHE. Operando XAS, XES, and ATR-FTIR directly link the evolution of spin-selective Co sites with specific NO₃RR intermediates, revealing that spin-selective Co sites lower hydrogenation barriers and accelerate key steps. These results demonstrate that spin-selective anti-perovskite frameworks provide a robust, earth-abundant platform for high-performance nitrate-to-ammonia electrocatalysts.