P-Block Antimony Single-Atom Catalysts for Nitric Oxide Electroreduction to Ammonia

Abstract

Electrocatalytic NO reduction to NH3 (NORR) offers a prospective approach to attain both harmful NO removal and efficient NH3 electrosynthesis. Main-group p-block metals are promising NORR candidates but still lack adequate exploration. Herein, p-block Sb single atoms confined in amorphous MoO3 (Sb1/a-MoO3) are designed as an efficient NORR catalyst, exhibiting the highest NH3 yield rate of 273.5 μmol h–1 cm–2 and a NO-to-NH3 Faradaic efficiency of 91.7% at −0.6 V vs RHE. In situ spectroscopic characterizations and theoretical computations reason that the outstanding NORR performance of Sb1/a-MoO3 arises from the isolated Sb1 sites, which can optimize the adsorption of *NO/*NHO to lower the reaction energy barriers and simultaneously exhibit a higher affinity to NO than to H2O/H species. Moreover, our strategy can be extended to prepare Bi1/a-MoO3, showing a high NORR property, demonstrating the immense potential of p-block metal single-atom catalysts toward the high-performing NORR electrocatalysis.