Structural and photocatalytic properties of co-doped hybrid ZrO 2 –TiO 2 photocatalysts

In this study, pure TiO 2 , ZrO 2 , and hybrid ZrO 2 –TiO 2 photocatalysts were synthesized through solgel process and calcined at three different temperatures. The synthesized photocatalysts were characterized using powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FESEM), Brunauer–Emmet–Teller (BET), ultraviolet–visible (UV–Vis) spectrometer, and photoluminescence (PL) spectrometer. The PXRD patterns show that the rutile phase of TiO 2 was suppressed through co-doping with ZrO 2 and produced small crystallite size. The hybrid photocatalysts with small crystallite size recorded the highest surface area of 114.7 m 2 /g compared to pure TiO 2 and ZrO 2 photocatalysts as confirmed by BET analysis. Irregular size and shape was observed in the hybrid photocatalysts compared to spherical shape and size in TiO 2 and flaky shape in ZrO 2 as shown by the FESEM images. The optical properties of the photocatalysts investigated using UV–Vis spectroscopy showed a decrease in band gap energy of pure TiO 2 through linear extrapolation from the Tauc’s plot despite the slightly higher band gap energy of the hybrid photocatalysts. However, PL analysis showed that doping of ZrO 2 into TiO 2 increased the separation efficiency of the electron–hole pairs and enhanced the photocatalytic activity. The phenol degradation of the hybrid ZrO 2 –TiO 2 photocatalysts was higher compared to those of the pure TiO 2 and ZrO 2 .