Photocatalytic H 2 evolution activity of CuO/ZrO 2 composite catalyst under simulated sunlight irradiation

Zirconia-supported CuO (CuO/ZrO 2 ) composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO 2 materials were also prepared by solid state reaction and co-precipitation method. The as-prepared powders were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), and thermogravimetric-differential thermal analysis (TG-DTA). The photocatalytic activity of CuO/ZrO 2 catalyst was investigated based on the H 2 evolution from oxalic acid solution under simulated sunlight irradiation. The effects of molar ratio of CuO to ZrO 2 , preparation method, phase change with the calcination temperature and the durability on the photocatalytic activity of the photocatalyst were investigated in detail. It is found that the optimal activity of photocatalytic H 2 evolution (2.41 mmol·h −1 μ −1 ) can be obtained when CuO/ZrO 2 composite photocatalyst is synthesized by sol-gel technique and the mole ratio of CuO to ZrO 2 is 40%. The activity of copper oxide supported on monoclinic ZrO 2 calcined at higher temperature is much higher than that on tetragonal ZrO 2 calcined at lower temperature, and the best calcination temperature is 900 °C.