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.

Rice-shaped Ti(3+) self-doped TiO(2-x) nanoparticles were synthesized by mild hydrothermal treatment of TiH(2) in H(2)O(2) aqueous solution. The structure, crystallinity, morphology, and other properties of the as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microcopy and X-ray photoelectron spectra. Electron paramagnetic resonance spectra confirm the presence of high concentration of paramagnetic Ti(3+) in the bulk and surface of the as-prepared samples. The particles showed a strong absorption across the UV to the visible light region and retained their light-blue color upon storage in ambient atmosphere or water for one month at 40 °C. The formation mechanism of Ti(3+) self-doped TiO(2-x) nanoparticles was discussed. Under visible light irradiation, the samples exhibit higher photocatalytic activity for hydrogen evolution and photooxidation of methylene blue than that of the commercial P25 TiO(2) nanoparticles. The sample obtained at 160 °C for 27 h showed a 9-fold enhancement for the visible light decomposition of methylene blue and 12.5 times higher for H(2) production in comparison to P25 TiO(2). The samples also showed an excellent cycling stability of the photocatalytic activity.

A novel Ag/AgBr/BiOBr hybrid was prepared by a rational in situ ion exchange reaction between BiOBr hierarchical microspheres and AgNO(3) in ethylene glycol followed by light reduction, which displayed superior visible light driven photocatalytic activities in sterilization of pathogenic organism and degradation of organic dye compared to N-doped P25.

Three anisotropic Pt-covered, Pt-edged, and Pt-tipped Au triangular nanoprisms (TNPs) were prepared by controlling the overgrowth of Pt as photocatalysts for H2 generation. With strong electric field and more interface for the hot electrons transfer, the H2 generation rate of Pt-edged Au TNPs was 3 and 5 times higher than those of Pt-tipped and Pt-covered Au TNPs. Single-particle photoluminescence (PL) spectra and finite-difference-time-domain (FDTD) simulations demonstrated that dipole surface plasmon resonance (DSPR) of Au TNPs enhanced the hot electrons transfer from Au to Pt leading to H2 generation. SPR bands of Au TNPs depending on the size play an important role on the photocatalytic activity of Pt-edged Au TNPs.

The new plasmonic photocatalyst Ag@Ag(Br,I) was synthesized by the ion-exchange process between the silver bromide and potassium iodide, then by reducing some Ag(+) ions in the surface region of Ag(Br,I) particles to Ag(0) species. Ag nanoparticles are formed from Ag(Br,I) by the light-induced chemical reduction reaction. The Ag@Ag(Br,I) particles have irregular shapes with their sizes varying from 83 nm to 1 mum. The as-grown plasmonic photocatalyst shows strong absorption in the visible light region because of the plasmon resonance of Ag nanoparticles. The ability of this compound to reduce Cr(VI) under visible light was compared with those of other reference photocatalyst. The plasmonic photocatalyst is shown to be highly efficient under visible light. The stability of the photocatalyst was examined by X-ray diffraction and X-ray photoelectron spectroscopy. The XRD pattern and XPS spectra prove the stability of the plasmonic photocatalyst Ag@Ag(Br,I).