open access

https://hdl.handle.net/2115/70812

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

英語

3D-FDTD simulations

2018-12-05

Elsevier

Applied Catalysis B: Environmental

237

574-587

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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© 2018 Zhishun Wei, Marcin Janczarek, Maya Endo, Kunlei Wang, Armandas Balčytis, Akio Nitta, Maria G. Méndez-Medrano, Christophe Colbeau-Justin, Saulius Juodkazis, Bunsho Ohtani, and Ewa Kowalska

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