Indoor air quality (IAQ) plays an important role on human health. Nitric oxides (NO and NO2), and volatile organic compounds, VOCs (such as formaldehyde, benzene) are typical inorganic and organic indoor air pollutants. They normally originate from cooking, combustion, tobacco smoke, furniture, building materials. They may also associate with traffic pollutants from outside of the building and can cause serious health problems like drowsiness, headache, sore throat, and mind fatigue. The U.S. Environmental Protection Agency, USEPA, points out that indoor air pollution is a much greater risk to human health than outdoor air pollution particularly in big cities where the average person spends more than 90% of his time indoors. So, it is of vital importance to remove these pollutants in order to improve the indoor air quality for people's health.
The most promising and effective method for air purification is Photocatalysis, a method considered as the most advance oxidation process to resolve environmental problems. Metal oxide semiconductors such as TiO2 and ZnO are commonly used as photocatalysts. TiO2 photocatalyst in particular has been extensively studied for air depollution due to its low cost, innoxiousness, chemical inertness, and high photocatalytic efficiency under UV light. However, the UV light is only 0.001–0.05 W/m2 in indoor illumination systems. To extend TiO2 as photocatalyst to visible light region, it is necessary to dope TiO2 with metals and nonmetals.
In this work we will report on the synthesis and characterization of TiO2 materials doped with transition metals in different concentrations capable to absorb and activate under visible light irradiation. We will report on Manganese (Mn) doped TiO2 powders prepared by a modified sol gel method. The novelty of the reported material is that it acts as an effective pollutant reducing agent, is harmless to humans and suitable for indoor applications. The crystal structure, particle size, morphology, and porosity along with surface morphology and elemental analysis of the materials are presented and photocalytic efficiencies are reported both for material in powder form and as additives in a number of building material matrices.