ZnO/Ag heterostructures embedded in Fe3O4 nanoparticles for magnetically recoverable photocatalysis

Abstract

Hybrid nanostructures made up of plasmonic noble metals (PNMs) and ZnO hold great promise of enhancing photocatalytic dye degradation rates, due to the remarkable abilities of PNMs like concentration of energetic photons, scattering of photons and exhibition of surface plasmon resonance (SPR). In order to effectively reuse the ZnO/Ag heterostructures for several catalytic reactions, we have coupled with Fe3O4 nanoparticles (NPs). Respective indications from the structural and morphological analysis are the phase purity and particle nature of the composite materials. Fe3O4/ZnO/Ag nanocomposite has showed the saturation magnetization (Ms) of 57.2 emu g−1. Characteristic SPR peak of Ag NPs at 450 nm along with the band edge absorption of ZnO at ∼370 nm are observed in the nanocomposite from the absorption graphs. Schottky contact occurrence between ZnO and Ag NPs is realized from the shift in the SPR peak position and also from the quenching of emission intensity of Fe3O4/ZnO composite for Ag incorporation. For illumination of visible photons, SPR of Ag NPs forms the energy electrons in the Fermi level of metal particles (Efm) then they fall into the Fermi level of ZnO (Efs) and are further trapped by the Fe3+ ions. This serious of electron separation process greatly enhance the methylene blue (MB) degradation rate. This electron transmigration is consistent at the interfaces of ternary nanocomposite, which aids the consistent degradation rate for several reaction cycles. Spine of the reaction behind the excellent photocatalytic reaction, (i.e.) electron transfer mechanism, is well illustrated and discussed in detail.