Atomically dispersed Palladium-Ethylene Glycol- Bismuth oxybromide for photocatalytic nitrogen fixation: Insight of molecular bridge mechanism

Abstract

Performance of single-atom catalysis largely depends on the interaction between the metal and the supporter. Herein, ethylene glycol (EG) was used as a molecular bridge connecting Palladium (Pd) and bismuth oxybromide (BiOBr) to form atomically dispersed Pd catalyst (Pd-EG-BiOBr) for photocatalytic nitrogen fixation under ambient conditions. Compared with 0.20 wt% Pd-BiOBr, 0.20 wt% Pd-EG-BiOBr greatly promoted the photocatalytic nitrogen fixation activity, affording an ammonia formation rate of 124.63 μmol·h−1. The molecular bridge mechanism during catalyst formation and photocatalysis is speculated based on Transmission electron microscopy, In-situ Fourier transform infrared spectra, Electron spin resonance spectra, UV–vis diffuse reflectance spectra, Photoluminescence spectra and Density Functional Theory calculations. The results show that EG not only induces the formation of atomically dispersed Pd, but also enhances the electron density of Pd and activation capacity of nitrogen molecules. This work opens a new door to applications of atomically dispersed Pd supported catalysts for high efficiency photocatalytic nitrogen fixation.