Facile preparation and enhanced photocatalytic H2-production activity of Cu(OH)2 cluster modified TiO2

Cu(OH)(2) cluster-modified TiO2 (Cu(OH)(2)/TiO2) photocatalysts were prepared by a simple precipitation method using Degussa P25 TiO2 powder (P25) as a support and copper nitrate as a precursor. Low-power ultraviolet light emitting diodes (UV-LEDs) were used as the light source for a photocatalytic water splitting reaction. The prepared samples show especially high photocatalytic H-2-production activity from aqueous solutions containing ethylene glycol as sacrificial reagent even without a Pt co-catalyst. The optimal Cu(OH)(2) loading content was found to be 0.29 mol%, giving an H-2-production rate of 3418 mu mol h(-1) g(-1) with a quantum efficiency (QE) of 13.9%, which exceeded the rate on pure TiO2 by more than 205 times. This high photocatalytic H-2-production activity is attributed to the presence of Cu(OH)(2) clusters on the surface of the TiO2. The potential of Cu(OH)(2)/Cu (Cu(OH)(2) + 2e(-) Cu + 2OH(-), E-o = -0.224 V) is slightly lower than conduction band (-0.26 V) of anatase TiO2, whilst being higher than the reduction potential of H+ (2H(+) + 2e(-) = H-2, E-o = -0.000 V), which favors the electron transfer from the CB of TiO2 to Cu(OH)(2), and the reduction of H+, thus enhancing photocatalytic H-2-production activity. This work not only shows a possibility for the utilization of low cost Cu(OH)(2) clusters as a substitute for noble metals (such as Pt) in photocatalytic H-2-production, but also for the first time exhibits a facile method for enhancing H-2-production activity by using hydroxide as a co-catalyst