Fe incorporation and modulation of oxygen vacancies in ZnO nanoparticles for photocatalytic degradation of Rhodamine B

Abstract

In this study, self-assembled ultrafine nanoclusters of Fe₂O₃ supported with defective Fe-doped ZnO nanoparticles (NPs) prepared via calcination of a Fe/Zn precursor in the presence of deep eutectic solvents (DES) complex. During the calcination process, surface defects are generated through the decomposition of Fe/Zn precursor with DES complex, simultaneously crystallinity of catalysts improved. The hexagonal wurtzite structure of ZnO NPs is retained after the incorporation of Fe atoms into the ZnO crystal lattice. Notably, the particle size is reduced from 32 to 22 nm after Fe incorporation due to alterations in the nucleation center in the DES. Electron paramagnetic resonance analysis reveals a broad peak at a g value of 2.0, attributed to Fe³⁺ atoms doped into ZnO matrix. These doped Fe³⁺ atoms create additional active sites on the surface of NPs, leading to an extended photoluminescence lifetime of the Fe₂O₃/ZnO nanocomposite. Consequently, the optimized V_o-Fe/ZnO nanocomposite achieves a 95 % removal efficiency for Rhodamine B (RhB) degradation with a rate constant (k) of 0.0755 min⁻¹. Additionally, nanocomposite shows visible light photo-Fenton activity for RhB degradation with k of 0.0069 min⁻¹.