Construction of MoS42− intercalated NiAl-layered double hydroxide by solvent-free method for promoting photocatalytic degradation of antibiotics: Synergistic effect of oxygen vacancies and electron-rich groups

Abstract

MoS42− intercalated NiAl-layered double hydroxides (LDH) were prepared by solvent-free techniques, which possessed oxygen vacancies and efficient electron transfer channels. Oxygen vacancies were increased with increasing of the MoS42− intercalation amount. Through X-ray Photoelectron Spectroscopy (XPS), Electron Paramagnetic Resonance (EPR), Kelvin Probe Force Microscopy (KPFM), and Density Functional Theory (DFT), the presence of oxygen vacancies and electron transfer channels were confirmed. In the meantime, the formation mechanisms of electron transfer channels and the synergistic mechanisms involving oxygen vacancies and electron transfer channels were illustrated. Electrochemical characterization revealed that compared with LDH, the electron lifetime of LDH-WM-0.5 increased from 1.70 ns to 2.88 ns, and the recombination efficiency of electron holes was reduced by about 6 times. Degradation experiments demonstrated that the degradation rate of tetracycline by LDH-WM-0.5 increased from 19.0 % to 90.0 % in 3 h, representing a 4.5-fold improvement compared to LDH photocatalysts. This study contributed novel insights into developing advanced photocatalysts by strategically manipulating the presence of oxygen vacancies and constructing the electron transfer channels.