title: Nanoscale strontium titanate photocatalysts for overall water splitting.
abstract: SrTiO(3) (STO) is a large band gap (3.2 eV) semiconductor that catalyzes the overall water splitting reaction under UV light irradiation in the presence of a NiO cocatalyst. As we show here, the reactivity persists in nanoscale particles of the material, although the process is less effective at the nanoscale. To reach these conclusions, Bulk STO, 30 ± 5 nm STO, and 6.5 ± 1 nm STO were synthesized by three different methods, their crystal structures verified with XRD and their morphology observed with HRTEM before and after NiO deposition. In connection with NiO, all samples split water into stoichiometric mixtures of H(2) and O(2), but the activity is decreasing from 28 μmol H(2) g(-1) h(-1) (bulk STO), to 19.4 μmol H(2) g(-1) h(-1) (30 nm STO), and 3.0 μmol H(2) g(-1) h(-1) (6.5 nm STO). The reasons for this decrease are an increase of the water oxidation overpotential for the smaller particles and reduced light absorption due to a quantum size effect. Overall, these findings establish the first nanoscale titanate photocatalyst for overall water splitting.
authors: Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors: Troy K
authors: TK
authors: Townsend
authors: Nigel D
authors: ND
authors: Browning
authors: Frank E
authors: FE
authors: Osterloh
mesh_terms: D006859:Hydrogen / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects*; D010087:Oxides / Q000737:chemistry* / Q000528:radiation effects; D010100:Oxygen / Q000737:chemistry* / Q000528:radiation effects; D013324:Strontium / Q000737:chemistry* / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014867:Water / Q000737:chemistry*
chemical_list: D010087:Oxides; D014867:Water; D006859:Hydrogen; D014025:Titanium; C119252:strontium titanium oxide; D010100:Oxygen; D013324:Strontium