Advances in photocatalytic NOx abatement through the use of Fe2O3/TiO2 nanocomposites

Abstract

Supported Fe₂O₃/TiO₂ nanocomposites were prepared for the first time by a plasma-assisted route and successfully tested in photocatalytic NO_x abatement driven by solar illumination. In particular, a sequential low-temperature (<100 °C) plasma enhanced-chemical vapor deposition (PE-CVD)/radio frequency (RF) sputtering approach was used to fabricate Fe₂O₃/TiO₂ nanocomposites with controlled composition and morphology. The preparation process was accompanied by a thorough multi-technique investigation carried out by complementary techniques, including X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and atomic force microscopy (AFM). The results evidenced the formation of high purity nanocomposites, in which TiO₂ content could be tailored by controlled variations of the sole sputtering time, and characterized by an intimate Fe₂O₃/TiO₂ contact, of key importance to exploit the chemical and electronic coupling between the two oxides. The obtained nanomaterials were tested in NO photo-oxidation activated by sunlight, showing a remarkable activity in NO_x (NO + NO₂) removal and a high selectivity (>60%) in their conversion to nitrate species. Overall, the present performances candidate the present photocatalysts as valuable materials for next-generation technologies aimed at the abatement of harmful gaseous pollutants.