Journal Article Noble metal-modified faceted anatase titania photocatalysts: Octahedron versus decahedron

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

237pp.574 - 587 , 2018-12-05 , Elsevier
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).

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