Pt-modified Au nanorods (NRs) synthesized by anisotropic overgrowth were used for producing H2 under visible and near-infrared light irradiation. The Pt-tipped sample exhibited much higher activity compared with fully covered samples. Using single-particle spectroscopies combined with transmission electron microscopy, we observed obvious quenching phenomena for photoluminescence and light scattering from individual Pt-tipped NRs. The analysis of energy relaxation of plasmon-generated hot electrons indicates the electron transfer from the excited Au to Pt.

Plasmonic bimetal nanostructures can be used to drive the conventional catalytic reactions efficiently at low temperature with the utilization of solar energy. This work developed Pd-modified Au nanorods, which work as the light absorber and the catalytically active site simultaneously, and exhibit efficient plasmon-enhanced catalytic formic acid dehydrogenation even when below room temperature (5 °C). Plasmon-induced interface interaction and photoreaction dynamics of individual nanorods were investigated by single-particle photoluminescence measurement, and a complete quenching phenomenon at the LSPR region was observed for the first time. More importantly, the spatial distribution of the SPR-induced enhancement, analyzed by the finite difference time domain (FDTD) simulation, shows that only tip-coated Pd can be affected for the occurrence of plasmon resonance energy transfer. This finding provides a route to decrease the amount of Pd species by the selective deposition only at the field-enhanced sites.

We developed a facile in situ method of preparing noble-metal plasmonic photocatalysts M@TiO 2 (M ¼ Au, Pt, Ag). In this method, the UV irradiation of TiO 2 powder dispersed in absolute ethanol generates some Ti 3+ ions on the surface of TiO 2 particles and these Ti 3+ ions, upon addition of a noblemetal salt in the dark, reduce the metal cations to deposit metal nanoparticles on the TiO 2 surface. This Ti 3+ -ion-assisted synthesis leads to a homogeneous loading of noble-metal nanoparticles on the surface of TiO 2 particles, which allows photocatalytic reactions to take place under visible-light on the whole TiO 2 surface. Among the three photocatalysts M@TiO 2 (M ¼ Au, Pt, Ag), Au@TiO 2 exhibits a high yield (63%) and selectivity (91%) for the oxidation of benzene to phenol in aqueous phenol. For this photocatalytic reaction, our study suggests a mechanism in which the visible-light absorption by the Au nanoparticles causes electron transfer from the Au nanoparticles to the TiO 2 particle, and the electrondepleted Au oxidizes phenoxy anions to form phenoxy radicals that oxidize benzene to phenol.

Cu 2 O microcrystals with well-formed facets were synthesized by a simple hydrothermal method. The surface stabilities and photocatalytic properties of Cu 2 O microcrystals were systematically investigated. Cu 2 O {100} and {110} facets gradually disappear and transform into nanosheets during the photodegradation of methyl orange (MO) dye. With the increase of irradiation time, Cu 2 O microcrystals completely transform into nanosheets with {111} facets. The finally formed nanosheets exhibit stable photocatalytic activities. On the basis of both experimental analysis and theoretical calculations, a novel model of charge separation among crystal faces was proposed and the morphology transformation mechanism accompanied by MO bleaching was discussed. It is concluded that Cu 2 O exposing {111} facets can be used as a stable photocatalyst.

By means of a simple ion-exchange process (using different precursors) and a light-induced chemical reduction reaction, highly efficient Ag@AgCl plasmonic photocatalysts with various self-assembled structures-including microrods, irregular balls, and hollow spheres-have been fabricated. All the obtained Ag@AgCl catalysts were characterized by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and UV-visible diffuse reflectance spectroscopy. The effect of the different morphologies on the properties of the photocatalysts was studied. The average content of elemental Ag in Ag@AgCl was found to be about 3.2 mol %. All the catalysts show strong absorption in the visible-light region. The obtained Ag@AgCl samples exhibit enhanced photocatalytic activity for the degradation of organic contaminants under visible-light irradiation. The stability of the plasmonic photocatalysts was also investigated in detail.