Biomimetic FeMo(Se, Te) as Joint Electron Pool Promoting Nitrogen Electrofixation

Abstract

It has been long believed that the FeMoS structure, where Fe is bonded with S, plays a pivotal role as a biomimetic catalyst for electrochemical nitrogen (N₂ ) fixation. Nevertheless, the structure of Fe bonded to heavier analogues (Se or Te) has never been explored for N₂ electrofixation. Here, we theoretically predict the electronic structure of FeMo(Se, Te) composed of tri-coordinated Fe species with open shells for binding with Se, which forms a joint electron pool for promoting N₂ activation. Guided by this interesting prediction, we then demonstrate a two-step procedure to synthesize such structures, which display remarkable N₂ electrofixation activities with an ammonia yield of 72.54 μg h^-1 mg^-1 and a Faradic efficiency of 51.67 % that are more than three times of the FeMoS counterpart. Further mechanism studies have been conducted by density function theory (DFT) simulations. This work provides new clues for designing versatile electrocatalytic materials for large-scale industrialization.