Photocatalytic decomposition of gaseous HCHO by Zr_xTi _1-xO₂ catalysts under UV-vis light irradiation with an energy-saving lamp

TiO₂, a widely used, inexpensive white powder, has been considered the most promising photocatalyst for the degradation of formaldehyde in air. However, the application of TiO₂ without other metal and nonmetal doping is limited because it requires UV activation with a high-energy band gap, and <5% of the solar radiation reaching the earth's surface can be used. To improve the photocatalytic performance of TiO₂, sol-gel nano TiO₂ with Zr doping can be activated by the UV-vis radiation available in sunlight to perform solar photocatalysis. The properties of the Zr_xTi_1-xO₂ catalysts were fully characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). Our results demonstrate that the optical response of TiO₂ was shifted from UV to the visible light region with the introduction of zirconium. The photocatalytic tests indicated that the Zr_xTi_1-xO₂ catalyst demonstrated higher activity for the degradation of formaldehyde compared with P25 and TiO₂ under UV-vis light irradiation with an energy-saving lamp.