Photocatalytic Evaluation of TiO2 Modified with N and Cu for Visible Absorption

Air quality is considered an essential issue for outdoor and indoor environments as we spend more than 90% of our time in indoor environments. For this reason, it is necessary to create systems and different techniques that allow the reducing typical indoor air pollutants, such as air purification systems with high efficiency and low energetic cost. This study aimed to synthesize photocatalysts based on TiO2, doped with nitrogen and copper with visible radiation and tested in the gas phase. Photocatalysts were prepared with nitrogen-doped titanium dioxide and other copper (I) oxide compounds. N-TiO2 preparation was tested at different calcination temperatures, using urea as a nitrogen precursor and TiO2 PC500 (Tronox) (N500). Another composite was prepared with Cu2O and N-TiO2 to generate the activation on the visible spectrum of the photocatalyst (CuN500). These were supported on the glass plates using the slurry of these materials and TiO2 sol–gel. The activity was tested using trichloroethylene (TCE) in the gas phase as VOCs model with UVA light, fluorescent light with and without a filter in a plate reactor using continuous flow at 300 mL min−1. The results using N500 presented 94%, 38% and 8.9% of efficiency using UVA and visible light and visible light with UVA filter, respectively. Lower TCE conversions were obtained using the photocatalyst containing copper. Finally, the TiO2 doped with N results show an excellent application for air decontamination using visible light. CuN500 could be more efficient for disinfection applications.