Dual Active Centers Bridged by Oxygen Vacancies of Ruthenium Single-Atom Hybrids Supported on Molybdenum Oxide for Photocatalytic Ammonia Synthesis.

Abstract

Photocatalytic synthesis of ammonia (NH3 ) holds significant potential compared with the Haber-Bosch process. However, the reported photocatalysts suffer from low efficiency owing to localized electron deficiency. Herein, Ru-SA (single atoms)/Hx MoO3-y hybrids with abundant of Mon+ (4<n<6) species neighboring oxygen vacancies (OV ) are synthesized via a H-spillover process. Detailed characterizations demonstrate that Ru-SA/Hx MoO3-y hybrids can quantitatively produce NH3 from N2 and H2 through the presence of dual active centers (Ru SA and Mon+ ). The Ru SA boost the activation and migration of H2 , and Mon+ species act as the trapping sites of localized electrons and the adsorption and dissociation sites of N2 , finally leading to NH3 synthesis on Mon+ -OH. The NH3 generation rate is up to 4.0 mmol h-1 g-1 , accompanied by an apparent quantum efficiency over 6.0 % at 650 nm.