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

Supported Fe2O3/TiO2 nanocomposites were prepared for the first time by a plasma-assisted route and successfully tested in photocatalytic NOx 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 multitechnique 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 NOx (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.