Photocatalytic decomposition of gaseous HCHO by ZrxTi1−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 ZrxTi1−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 ZrxTi1−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.

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► Photocatalytic oxidation of gaseous HCHO by ZrxTi1−xO2 samples under visible-light irradiation was discussed.
► With increasing the hydroxyl groups, the activity of samples of ZrxTi1−xO2 was increased.
► The result shows that L–H model is valid at the beginning of catalytic oxidation.
► The photocatalytic activitie of Zr0.08Ti0.92O2 samples was affected by the humidity of air.