Preparation and photocatalytic properties of porous C and N co-doped TiO2 deposited on brick by a fast, one-step microwave irradiation method

A one-step microwave irradiation method was used to deposit carbon and nitrogen co-doped TiO 2 ((C, N)-TiO 2 ) on commercial brick ((C, N)-TiO 2 /brick). The as-prepared samples were characterized by X-ray diffraction, ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). A selective technique was also used to investigate the concentration of hydroxyl radicals during UV–vis irradiation of the Methyl Orange solution with the as-prepared samples. The C and N dopants enhanced visible light absorption and provided a longer lifetime for the photo-generated electron–hole pairs. The SEM images showed that the as-prepared sample is porous. The dark adsorption and photodegradation test for (C, N)-TiO 2 /brick showed good photodegradation and good recyclability . The best photodegradation rate was 94% after 2   hr. The maximum degradation rate was maintained even after the 6th cycle. The good photocatalytic properties are attributed to the enhanced visible light absorption , enhanced pollutant adsorption arising from the porous structure of the (C, N)-TiO 2 thin film , and longer lifetime of the photo-generated electron–hole pairs. (C, N)-TiO 2 /brick should have potential commercial applications in photodegradation processes because of its low cost, good photodegradation, and excellent recyclability .