Methane production by CO2 photo-reduction in the presence of TiO2 modified by Nickel and Copper

Carbon dioxide photocatalytic reduction is one of the promising methods used to produce a wide range of renewable hydrocarbon fuels using sunlight in the presence of photocatalysts. In this study, a series of nickel-doped titanium dioxide samples (0.5, 1, and 1.5 wt%) Were synthesized by Sol-gel method. After performing photocatalytic carbon dioxide recovery experiments and finding the optimum percentage of nickel, titanium dioxide sample with 1 wt% nickel (TNi1) showed the highest photocatalytic activity. Then, by impregnation method, 3% by weight of Cu (1, 2 and 3 wt%) was loaded onto the TNi1 structure. Finally, the sample loaded with 1 wt% copper on titanium dioxide doped with 1 wt% Ni (1Cu/TNi1) showed the highest photocatalytic activity and methane production was 12.6 μmol/gcat that was about 4 times higher than the amount of methane produced in the presence of pure TiO2. The synthesized nanophotocatalysts were characterized using X-ray diffraction (XRD) analysis, diffuse reflectance spectroscopy (DRS) analysis and photoluminescence (PL) analysis. Also, their specific surface area was measured by BET method and morphology of the particles was investigated by field emission scanning electron microscopy.