CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry(XRD) as well as scanning electron microscopy(SEM).The effects of calcination temperature,category of sacrificial reagent,initial sacrificial reagent concentration,and Ag loading content on the photocatalytic activity of the as-obtained CuO sample were investigated.The results show that the as-obtained CuO exhibits high activity for photocatalysis of H2 evolution reaction(HER) in oxalic acid solution under simulated sunlight irradiation.The highest photocatalytic activity of the as-obtained CuO was achieved at the calcination temperature of 1000℃,and oxalic acid was used as the sacrificial reagent with the concentration 0.05 mol/L.H2 evolution rate is as high as 2.98 mmol/(h·g) with 2%(mass fraction) loaded Ag.The possible photocatalytic reaction mechanism on the CuO photocatalyst for HER in oxalic acid solution was also discussed.
Zirconia-supported CuO(CuO/ZrO2) composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique.For comparison,CuO/ZrO2 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/ZrO2 catalyst was investigated based on the H2 evolution from oxalic acid solution under simulated sunlight irradiation.The effects of molar ratio of CuO to ZrO2,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 H2 evolution(2.41 mmol·h-1·g-1) can be obtained when CuO/ZrO2 composite photocatalyst is synthesized by sol-gel technique and the mole ratio of CuO to ZrO2 is 40%.The activity of copper oxide supported on monoclinic ZrO2 calcined at higher temperature is much higher than that on tetragonal ZrO2 calcined at lower temperature,and the best calcination temperature is 900 ℃.
