Development of Cu/Ti02 Photocatalyst for Hydrogen Production under Visible Light

Technologies for generating hydrogen from water usmg modified photocatalyst have drawn many attentions. In this study the photocatalysis for hydrogen generation were synthesized us1ng two methods; complex-precipitation and wet impregnation method. Cu/Ti02 with 2, 5, I 0 and 15 wt% loading was prepared, dried and prior to calcination, thermal gravimetric analysis was carried out to determine their thermal stability. Based on the thermograms, the calcination temperature was estimated to be 300°C or higher. Therefore, the photocatalysis were calcined at 300°C, 400°C and 500°C for 30 min. The effect of transition metal loading and calcination temperatures on the photocatalytic activity was investigated. Photocatalytic activity was carried out under visible light illumination (500 W halogen lamp as the light source). The screening process is used to monitor the photocatalytic activities for hydrogen production in a multipart reactor containing of photocatalyst, water and methanol (as scavenger). For all photocatalysis, the highest amount of hydrogen produced was 8.5 mLg-1h-1 for Cu/Ti02 calcined at 300°C C for 30 min prepared using complex-precipitation method. The amount of hydrogen produced decrease as the calcination temperature increases for all the catalysts. The photocatalysis were also characterized using Temperature Programmed Reduction (TPR), Diffuse Reflectance UV-Yis (DR-UV-Vis), Field Emission Scanning Electron Microscope (FE-SEM), Fourier Transform lnfared (FTIR), X-ray Difractometer (XRD) and surface area determination (BET). The results from TPR and XRD indicated that the only Cu species present was CuO supported on Ti02. The SEM micrographs showed morphology of the prepared samples with particle size around 20 nm to I 00 nm. The effect of transition metal loading was studied and found that incorporating with copper enhance the photocatalytic activity compared to Ti02. However higher concentration of transition metal loading up to 15 wt% led to the decrement of the photocatalytic activity. The lower photocatalytic activity can be influence by the surface saturation of Cu which minimized the light penetration from reaching to the surface of the Ti02. The incorporation of Cu transition metal had successfully shifted the Ti02 band gap to a longer wavelength as evidence by DR-UV-Vis