Ag nanoparticles/hematite mesocrystals superstructure composite: a facile synthesis and enhanced heterogeneous photo-Fenton activity

Abstract

Mesocrystals, as a new class of crystals, compared to the more common single crystals and polycrystalline systems, have attracted unparalleled attention owing to their unique ordered superstructure. Herein, uniform, highly crystalline, nanoporous and cocoon-like hematite mesocrystals have been fabricated through a facile template-free approach in benzyl alcohol. They showed a relatively large surface area of 18.8 m² g⁻¹ and an average pore size of 3.67 nm, which was within the range of hole diffusion lengths (2–4 nm) of α-Fe₂O₃. The loading of Ag nanoparticles on the α-Fe₂O₃ mesocrystals had no distinct effect on the surface area and pore distribution. The results of photoluminescence and photoelectrochemical measurements indicated that the synergistic effect of the suitable pore size and Ag nanoparticles resulted in effective charge carrier transfer. Thus, the Ag/hematite mesocrystal composites displayed high photo-Fenton activity in the oxidation of Rhodamine B, methyl orange and glyphosate under visible light.