Efficient Photoelectrocatalytic Synthesis of Ammonia by Superionic Conductor with Mixed Ion/Electron Conduction
Xiaxin Wang, He Li, Yuxiu Zou, Hang Xiao, Wenkai Teng, Ben Chong, Mengyang Xia, Yang Li, Honghui Ou, Bo Lin, Guidong Yang
Abstract
Abstract Photoelectrochemical (PEC) nitrate reduction shows substantial potential for solar‐to‐ammonia (NH 3 ) conversion. However, low electron density and disordered electron conduction of conventional catalysts result in limited performance and low Faraday efficiency. Herein, a FePS 2.66 Li 0.87 superionic conductor (SIC) is developed by introducing lithium ions into van der Waals immobile layered of FePS 3 catalyst. This layered crystal framework facilitates high‐concentration lithium ions confinement and long‐range diffusion at room temperature, transitioning the conduction mechanism from electronic to mixed ionic/electronic. The typical nanofluidic ion transport leads to a high ionic conductivity of 16.4 mS cm −1 at room temperature and enhanced electronic conductivity of 5 × 10 −6 S cm −1 . Furthermore, mobile lithium ions within interlayers enhance the interaction between the low‐lying 3 d yz orbitals of Fe interacting with 2 a 2 empty antibonding orbitals of NO 3 − . An excellent PEC ammonia production of 134.18 µmol cm −2 h −1 with 96.95% Faradaic efficiency is achieved, and the corresponding solar‐to‐NH 3 efficiency of 57.13% offers a promising pathway toward sustainable ammonia production.