Atomically dispersed Pd on defective BN nanosheets for nitrite electroreduction to ammonia

Electrocatalytic NO₂^- reduction to NH₃ (NO₂RR) offers a prospective strategy to concurrently achieve polluted NO₂^- removal and effective NH₃ electrosynthesis. In this work, we report atomically dispersed Pd on defective BN nanosheets (Pd₁/BN) as an efficient catalyst for the NO₂RR, achieving the highest NH₃-Faradaic efficiency of 91.7% with an NH₃ yield rate of 347.1 μmol h^-1 cm^-2 at -0.6 V vs. RHE, superior to those of most previously reported electrocatalysts. Theoretical computations reveal the isolated Pd sites as catalytic centers to selectively adsorb NO₂^- and accelerate NO₂^--to-NH₃ hydrogenation process with a minimized reaction barrier, eventually contributing to the considerably enhanced NO₂RR selectivity and activity of Pd₁/BN.