Defect Pyrochlore‐Type Mott–Schottky Photocatalysts for Enhanced Ammonia Synthesis at Low Pressure
Zihan Zhao, Ruike Tan, Yuxiang Kong, Zihao Zhang, Shou Qiu, Xiaoyue Mu, Lu Li
Abstract
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.