The role of CuO in promoting photocatalytic hydrogen production over TiO2

The roles of metal co-catalysts and reaction media in photocatalytic hydrogen production: Performance evaluation of M/TiO2 photocatalysts (M = Pd, Pt, Au) in different alcohol–water mixtures

“…Fig. 4 shows photoluminescence (PL) data for P25 TiO 2 and the M/TiO 2 photocatalysts, and may be compared with our other recent works investigating photoluminescence behaviour of TiO 2 modified with Au, Pt or CuO co-catalysts [28,29,40]. Under 310 nm excitation, the un-modified P25 TiO 2 support gave an intense photoluminescence signal due to radiative e À -h + recombination following photoexcitation.…”

The advanced removal of benzene from aerosols by photocatalytic oxidation and adsorption of Cu–TiO 2 /PU under visible light irradiation

“…7); this is because the copper oxides gathered into larger particles on the surface of the TiO 2 . The large particles eclipsed the light reaching to the TiO 2 surface, resulting in a decrease in light absorption [52]. In addition, the gathering of copper oxide particles led to an uneven distribution of the particles on the TiO 2 layer or a decrease in the interfacial surface between the copper oxides and the TiO 2 .…”

Novel Au/TiO2 photocatalysts for hydrogen production in alcohol–water mixtures based on hydrogen titanate nanotube precursors

“…Whilst TiO 2 satisfies the key criteria above for a direct water splitting photocatalyst, it possesses low activity for H 2 production under solar or UV excitation owing to rapid electron-hole pair recombination following photo-excitation and the high overpotential for H 2 production on TiO 2 surfaces. These limitations can be overcome to some extent by adding sacrificial agents to water and depositing particular high work function metals (such as Ni, Pd, Pt or Au ) or suitable semiconductor co-catalysts on TiO 2 [38]. Both practices facilitate charge separation in TiO 2 and increase the number of charge carriers available for photoreactions that yield H 2 .…”

“…The sacrificial agents act as electron donors, consuming photogenerated holes in the TiO 2 valence band, whilst the metal co-catalysts serve as hydrogen evolution sites on the TiO 2 surface, accepting photo-excited electrons from the TiO 2 conduction band. Recent studies of M/TiO 2 photocatalysts, where M = Pd, Pt, Au or combinations thereof, have reported H 2 production rates as high as 30-40 mmol g À1 h À1 in alcohol-water systems under realistic solar UV fluxes [33][34][35][36][37][38][39], highlighting the potential of TiO 2 -based photocatalysts for future H 2 production. Optimal metal co-catalyst loadings appear to be 0.5 wt.% for Ni, Pd or Pt, and 1.5-4.0 wt.% for Au.…”