Abstract
Spherical LaFeO3 nanoparticles with an average size of 35 nm were synthesized by a polyacrylamide gel route. Ag nanoparticles of 8–18 nm in size were decorated onto LaFeO3 particle surface by a chemical reduction method to yield Ag–LaFeO3 composites. The samples were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy, and photoluminescence spectroscopy. It is found that LaFeO3 particles have two bandgap energies of 2.59 and 2.24 eV, which undergo almost no change when decorated with Ag nanoparticles. photoluminescence spectra demonstrate that the decoration of LaFeO3 particles with Ag nanoparticles leads to a decreased recombination rate of photogenerated electrons and holes. The photocatalytic activity of the samples was evaluated by degrading Rhodamine B under simulated-sunlight irradiation. Compared to bare LaFeO3 particles, Ag–LaFeO3 composites exhibit an obviously enhanced photocatalytic activity. The formed •OH was examined by photoluminescence spectroscopy using terephthalic acid as the •OH scavenger, revealing an enhanced yield on the irradiated Ag–LaFeO3 composites. To clarify the role of active species in the photocatalysis, the effect of ammonium oxalate (h+ scavenger), ethanol (•OH scavenger), benzoquinone (•O2 − scavenger), and N2 on the Rhodamine B degradation as well as the •OH yield was investigated. Based on the experimental results, •OH and •O2 − are suggested to be the main active species causing the dye degradation.
Published Version
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