Study on the preparation and photocatalytic oxidation properties of TiO2/nano-Fe0 photocatalysts

Abstract

TiO₂/nano-Fe⁰ composite photocatalysts were prepared via a liquid phase reduction deposition method using anatase nano-TiO₂ as a deposition substrate. The morphology and structure of TiO₂/nano-Fe⁰ photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis absorption spectra. The results showed that this composite photocatalyst can be homogeneously distributed and forms a jellyfish structure after combining with the TiO₂ nanoparticles. The composite of nano-Fe⁰ and TiO₂ could effectively compensate the consumption of nano-Fe⁰ and promote the generation of hydroxyl radicals (·OH) by a synergistic effect and the dynamic circulation reaction mechanism. Furthermore, the formation of a heterojunction structure between nano-Fe⁰ and TiO₂ not only makes this composite photocatalyst have a higher catalytic efficiency in the visible region by the photo-response redshift effect, but also blocks the recombination of the photogenerated electron–hole pairs. The degradation efficiency for the Acid Red B solution was used to evaluate the activity of this composite photocatalyst. The effects of pH, dissolved oxygen and nano-Fe⁰ loading ratio on degradation efficiency of the Acid Red B were investigated and optimized. This composite photocatalyst possessed the highest photocatalytic activity under acidic and oxic conditions with the optimal loading of Fe⁰ of 10 wt%. In addition, TiO₂/nano-Fe⁰ shows a higher catalytic activity than TiO₂ or nano-Fe⁰ alone. The XRD patterns of catalysts before and after reaction proved that this composite photocatalyst was durable and stable, which is due to the dynamic circulation reaction mechanism.