Defect Pyrochlore‐Type Mott–Schottky Photocatalysts for Enhanced Ammonia Synthesis at Low Pressure

Abstract The ambient ammonia synthesis coupled with distributed green hydrogen production technology can provide promising solutions for low‐carbon NH 3 production and H 2 storage. Herein, we reported Ru‐loaded defective pyrochlore K 2 Ta 2 O 6− x with remarkable visible‐light absorption and a very low work function, enabling effective visible‐light‐driven ammonia synthesis from N 2 and H 2 at low pressure down to 0.2 atm. The photocatalytic rate was 2.8 times higher than that of the best previously reported photocatalyst and the photo‐thermal rate at 425 K was similar to that of Ru‐loaded black TiO 2 at 633 K. Compared to perovskite‐type KTaO 3− x with the same composition, the pyrochlore exhibited a 3.7‐fold increase in intrinsic activity due to a higher photoexcited charge separation efficiency and a higher conduction band position. The interfacial Schottky barrier and spontaneous electron transfer between K 2 Ta 2 O 6− x and Ru further improve photoexcited charge separation and accumulate energetic electrons to facilitate N 2 activation.