Ag-Fe2O3 Heterostructured Nanoparticles as Photocatalysts under Visible Light Irradiation

Due to the synergistic effect between different composites, an increasing number of functional semiconductor-metal hybrid nanomaterials with core-shell or heterostructure geometry has been fabricated and proposed as the preferred form of catalysts. For example, Au@Co₃O₄ core-shell nanostructures showed higher oxygen evolution reaction activity than a mixture of Au and Co₃O₄ nanoparticles, or Co₃O₄ and Au nanoparticles alone. In addition, PbS-Ag heterostructure nanotubes exhibited significantly enhanced photocatalytic activity.

Thanks to the controlled syntheses of semiconductor-metal nanocomposites with desired morphologies, it has been feasible to study the nanostructure tuning capacities. Herein, Ag-Fe₂O₃ core-shell and heteromer nanocomposites were synthesized by a seed-mediated growth method reported previously, and hollow Fe₂O₃ nanoparticles were obtained by the transformation of  Ag-Fe₂O₃ core-shell nanocomposites. Subsequently, the photocatalytic activity of Ag-Fe₂O₃ core-shell nanocomposites was directly compared with that of Ag-Fe₂O₃ heteromer and hollow Fe₂O₃ nanoparticles, respectively. Finally, we could demonstrate experimentally whether the enhanced photocatalytic activity of Ag-Fe₂O₃ core-shell arise from its wide absorbance range of visible light and favorable charge separation. This investigation would help us to further understand nanostructure tuning capacity of nanocomposites and control their syntheses for a given application.