Iridium single-atom catalyst for highly efficient NO electroreduction to NH3

Abstract

Atomically dispersed Ir confined in amorphous MoO 3 (Ir 1 / a -MoO 3 ) was designed as a high-efficiency catalyst for electrochemical reduction reaction of NO to NH 3 (NORR). Atomic precise characterizations reveal that isolated Ir atoms are immobilized in O-vacancies of amorphous MoO 3 to form Ir 1 -O 5 moieties. Theoretical computations demonstrate that single-site Ir 1 -O 5 can not only powerfully activate and hydrogenate NO with a near-zero energy barrier, but also exhibit a higher affinity to NO over H adatoms to suppress the competing hydrogen evolution and promote both NORR activity and selectivity. Consequently, Ir 1 / a -MoO 3 shows the maximum NH 3 yield rate of 438.8 µmol·h −1 ·cm −2 and NH 3 -Faradaic efficiency of 93.2%, representing one of the most efficient NORR catalysts to date.