Photocatalytic water splitting for hydrogen production on Au/KTiNbO5

Gold nanoparticles were deposited on potassium titanoniobate, KTiNbO5 using deposition-precipitation (DP), conventional impregnation (IMP) and photodeposition method in order to improve photocatalytic hydrogen production from water splitting. The effect of synthesis pH value of a HAuCl4 aqueous solution used in the DP process on the morphology of gold nanoparticles, optical property and photocatalytic activity of water splitting under UV light irradiation was investigated. These catalysts were characterized by powder X-ray diffraction patterns (XRD), inductively coupled plasma mass spectrometry (ICP-MS), UV–visible spectroscopy (UV–vis), and Transmission Electron Microscopy (TEM). The Au/KTiNbO5 catalysts prepared by the DP method consisted of a good metal–semiconductor interface which allowed for a much higher efficient electron-hole separation. The 0.63 wt% Au/KTiNbO5 catalyst prepared by the DP method at pH = 10 showed a uniform dispersion of gold nanoparticles with an average gold particle size of 4.2 nm and exhibited an ultra-high photocatalytic water splitting activity (3522 μmol g−1 h−1), about 47 times higher than that exhibited by the KTiNbO5 photocatalyst.