Influence of nickel in the hydrogen production activity of TiO sub(2)

Sol-gel synthesised TiO sub(2) developed by our group was modified through the addition of nickel nitrate and ammonium carbonate in the synthesis process. Photocatalysts were synthesised with different Ni/Ti molar ratios (0.015,0.030, 0.045) and constant Ni/N ratio equal to 1.5 and subjected to post-calcination at temperatures of between 400 C and 700 C. Characterisation was carried out with: X-ray diffraction (XRD), UV-vis diffusive reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy-energy dispersive X-ray analysis (TEM-EDX), thermal analysis (TGA, DTA), aggregate size distribution, Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorptiondesorption isotherm (BET). Photoactivity in terms of photocatalytic hydrogen production was tested using a suspension of photocatalyst at 25 vol.% methanol. With a continuous flow of N sub(2) in headspace the hydrogen produced was conducted to a gas chromatograph for quantification. No evidence of the presence of N was found in the photocatalyst. However, the presence of Ni enhanced TiO sub(2) photoactivity, with a calcination temperature of 550 C resulting in the highest photoactivity value of 260.76 [mu]umolh super(-1).