We studied the Crx/Fe1−x (0.2 ≤ x ≤ 0.8) co-dopant ratio dependence on the visible light activity of TiO2 : [Cr-Fe] nanoparticles for photodecomposition of gaseous iso-propyl alcohol (IPA), as well as photo reduction of water. Nanoparticles of TiO2 : [CrxFe1−x] with an optimum value of x = 0.4 generated 2-4 times higher photocurrents. The optimum concentration shows maximum photodecomposition activity for IPA, as well as photocatalytic hydrogen generation under visible light (λ > 420 nm). The study on the ratio optimization of the co-dopant metals ions was found to be an important factor for devising an efficient photocatalyst. The optimum co-dopant ratio seems to yield favorable density of states in the band gap of TiO2, which otherwise would turn into recombination centers.
Keywords: TiO2, Nano-particles, Photocatalysts, Photodecomposition, hydrogen generation