Selective Deposition of Silver Nanoparticles onto WO3 Nanorods with Different Facets: The Correlation of Facet-Induced Electron Transport Preference and Photocatalytic Activity

WO3 nanorods with a regular hexagonal morphology and different exposed facets were fabricated by hydrothermal treatment, and then Ag nanoparticles (Ag NPs) selectively deposited onto hexagonal WO3 nanorods with different facets were also successfully synthesized through an in situ photoreduction method. The prepared samples were characterized by various analytical techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectra, and so on. The results illustrated that the intrinsic nature of charge separation on the {001} facets of WO3-110 nanorods and the surface plasmon resonance (SPR) effect both contribute to the enhancement of visible-light absorption and the decrease of the recombination of the photogenerated electron hole pairs. For comparison, Ag/WO3-110 catalysts with dominant exposed {001} facets exhibited much better photocatalytic activity than that of Ag/WO3-001 with a high percentage of exposed {100} and {010} facets for the degradation of organic pollutants (including rhodamine B, methyl orange, and so on) under the visible-light irradiation. In addition, the underlying photocatalytic reaction mechanism was further investigated by the controlled experiments using radical scavengers.