Nanostructured BiOI for air pollution control: Microwave-assisted synthesis, characterization and photocatalytic activity toward NO transformation under visible light irradiation

Abstract

In the last decades, air pollution control has received much attention due to the increase of environmental and health problems. The design of new materials with potential applications in air pollution control systems is a challenge nowadays. In this work, BiOI nanostructured materials were synthesized and used for photocatalytic oxidation of nitric oxide (NO). A microwave-assisted solvothermal method was successfully applied for BiOI synthesis at 126 °C, using ethylene glycol (EG) as a solvent. Several samples were prepared by varying the microwave irradiation time between 5 and 120 min. Resulting materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, diffuse reflectance spectroscopy (DRS) and photoluminescence measurements (PL). The photocatalytic activity of BiOI samples was evaluated in the photo-oxidation reaction of nitric oxide (NO) in gas phase under visible light irradiation. BiOI sample synthesized after 15 min of microwave exposition shows the highest photocatalytic activity, even greater than that obtained when TiO2 Evonik P-25 is used. This nanostructured material was applied into the formulation of two types of materials (ceramic paint and stucco) for its potential use in the construction industry. Preliminary results show that the application of nanostructured BiOI into stucco formulation has a great potential to develop commercial products to remove NO from air.