TiO₂ modification by gold (Au) for photocatalytic hydrogen (H₂) production

TiO₂ is indeed one of the widely used semiconductors employed for photocatalytic hydrogen production. Most of its photocatalytic activity is achieved in its crystalline form. However, its photocatalytic activity is limited to ultraviolet region. For making TiO₂ visible light active; Au deposition is strongly recommended due to its surface plasmon feature. Au deposition enhances the photocatalytic activity of both crystalline and nanocrystalline TiO₂. Efficiency of photocatalytic activity is controlled by shape and size of Au nanoparticle subsequently the synthetic methodology plays an important role. Herein, we furnish a brief description of TiO₂-Au nanocomposite synthesis by different methods viz. sol-gel, photodeposition, deposition-precipitation simple reducing method and dispersion method. A discussion on physical properties of the resultant material is also provided. Three different types of mechanism has been described depending on the type of irradiation and form of TiO₂ (crystalline and nanocrytalline). A comparative hydrogen production yield is also tabulated to get an idea about the best synthesis methodology and form of TiO₂ for efficient photocatalysis.