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  • Noble metal-modified facete...
    Wei, Zhishun; Janczarek, Marcin; Endo, Maya; Wang, Kunlei; Balčytis, Armandas; Nitta, Akio; Méndez-Medrano, Maria G.; Colbeau-Justin, Christophe; Juodkazis, Saulius; Ohtani, Bunsho; Kowalska, Ewa

    Applied catalysis. B, Environmental, 12/2018, Letnik: 237
    Journal Article

    Display omitted •Two-faceted (DAP) ― more favorable configuration than single-faceted (OAP) under UV irradiation.•Bare and modified DAP ― efficient charge carriers’ separation under UV irradiation.•Noble metal-modified OAP ― higher activity than respective DAP under vis irradiation.•“Hot” (plasmonic) electron transfer via shallow electron traps in OAP.•Localization of noble metal on DAP – key factor of vis activity. Octahedral anatase particles (OAP, with eight equivalent {101} facets) and decahedral anatase particles (DAP, with two additional {001} facets) were modified with nanoparticles of noble metals (Au, Ag, Cu). The titania morphology, expressed by the presence of different arrangements of exposed crystal facets, played a key role in the photocatalytic properties of metal-modified faceted titania. In the UV/vis systems, two-faceted configuration of DAP was more favorable for the reaction efficiency than single-faceted OAP because of an efficient charge separation described by the transfer of electrons to {101} facets and holes to {001} facets. Time-resolved microwave conductivity (TRMC) and reversed double-beam photoacoustic spectroscopy (RDB-PAS) confirmed that distribution of electron traps (ET) and mobility of electrons were key-factors of photocatalytic activity. In contrast, metal-modified OAP samples had higher photocatalytic activity than metal-modified DAP and metal-modified commercial titania samples under visible light irradiation. This indicates that the presence of single type of facets ({101}) is favorable for efficient electron transfer via shallow ET, whereas intrinsic properties of DAP result in fast charge carriers’ recombination when gold is deposited on {101} facets (migration of “hot” electrons: Au→{101}→Au).