Fe2O3-WO3 and Fe2O3-CuO nanoheterostructures by XPS

The detrimental effects of gaseous nitrogen oxides (NOx, with x = 1 and 2) on both human health and the environment have triggered efforts aimed at the development of solar-activated photocatalysts for their efficient removal. In this regard, Fe2O3-WO3 and Fe2O3-CuO nanoheterostructures were prepared by a two-step vapor phase route. In particular, chemical vapor deposition (CVD) of beta-Fe2O3, a scarcely investigated iron(III) oxide polymorph, was followed by radio frequency-sputtering of WO3 or CuO under mild conditions. The adopted strategy enabled the obtainment of nanoheterostructures with a peculiar pyramidal morphology and a uniform dispersion of CuO or WO3 onto the pristine iron(III) oxide. In this work, the chemical composition of the target systems was investigated by means of x-ray photoelectron and x-ray excited-Auger electron spectroscopies. In addition to the identification of elemental chemical states, the reported results confirmed the formation of pure and O-deficient systems, in which the direct interplay between the single components opens the door to air purification using the developed systems as photocatalysts.