Photocatalytic equipment with nitrogen-doped titanium dioxide for air cleaning and disinfecting

Thanh Son Le, Quoc Buu Ngo, Viet Dung Nguyen, Hoai Chau Nguyen, Trong Hien Dao, Xuan Tin Tran, E N Kabachkov and I L Balikhin

Abstract

Nitrogen-doped TiO₂ nanoparticle photocatalysts were synthesized by a sol–gel procedure using tetra-n-butyl orthotitanate as a titanium precursor and urea as a nitrogen source. Systematic studies for the preparation parameters and their impact on the material's structure were carried out by multiple techniques: thermogravimetric and differential scanning calorimetric analysis, x-ray diffraction, scanning electron microscope, transmission electron microscopy, energy dispersive x-ray spectroscopy and UV–Vis diffuse reflectance spectrophotometry showed that the nitrogen-doped TiO₂ calcined at 500 °C for 3 h exhibited a spherical form with a particle size about 15–20 nm and crystal phase presented a mixture of 89.12% anatase. The obtained product was deposited on a porous quartz tube (D = 74 mm; l = 418 mm) to manufacture an air photocatalytic cleaner as a prototype of the TIOKRAFT company's equipment. The created air cleaner was able to remove 60% of 10 ppm acetone within 390 min and degrade 98.5% of bacteria (total aerobic bacteria and fungi, 300 cfu m⁻³) within 120 min in a 10 m³ box. These photodegradation activities of N-TiO₂ are higher than that of the commercial nano-TiO₂ (Skyspring Inc., USA, particle size of 5–10 nm)