A sonication-assisted sequential chemical bath deposition (S-CBD) approach is presented to uniformly decorate CdS quantum dots (QDs) on self-organized TiO2 nanotube arrays (TNTAs). This approach avoids the clogging of CdS QDs at the TiO2 nanotube mouth and promotes the deposition of CdS QDs into the nanotubes as well as on the tube walls. The photoelectrochemical and photocatalytic properties of the resulting CdS-decorated TNTAs were explored in detail. In comparison with a classical S-CBD approach, the sonication-assisted technique showed much enhancement in the photoelectrochemical and photocatalytic activities of the CdS QDs-sensitized TNTAs.

A novel one-step sonochemical approach to synthesize a plasmonic photocatalyst of AgCl nanocubes (ca. 115 nm in edge length) with a small amount of Ag metal species is presented. The nanoscale Ag/AgCl hybrid photocatalysts with cubic morphology are readily formed under ambient ultrasonic conditions and neither external heat treatment nor reducing agents are required. The size of the Ag/AgCl photocatalysts could be controlled by changing the concentrations of Ag(+) ions and polyvinylpyrrolidone molecules in precursor solutions. The compositions, microstructures, influencing factors, and possible growth mechanism of the Ag/AgCl hybrid nanocubes were systematically investigated. The Ag/AgCl photocatalysts show excellent photocatalytic performance for degradation of various dye molecules under visible light.

We report that the use of a chemically deposited ZnO energy barrier between a CdS quantum dot sensitizer and TiO(2) nanotubes (TNTs) can improve the efficiency of quantum dots-sensitized solar cells (QDSCs). The experimental results show that the formation of the ZnO layers over TNTs significantly improved the performances of the CdS QDSCs based on the TNTs electrodes. In particular, a maximum photoconversion efficiency of 4.6% was achieved for the CdS/ZnO/TNTs electrode under UV-visible light illumination, corresponding to an increase of 43.7% as compared to the CdS/TNTs electrode without the ZnO layers. The improved CdS QDSCs efficiency is attributed to the suppressed recombination of photoinjected electrons with redox ions from the electrolyte resulting from the ZnO energy barrier layers.

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We present the synthesis and visible-light-induced catalytic activity of Ag(2)S-coupled TiO(2) nanoparticles (NPs) and TiO(2) nanowires (NWs). Through a simple wet chemical process from a mixture of peroxo titanic acid (PTA) solution, thiourea and AgAc, a composite of Ag(2)S NPs and TiO(2) NPs with sizes of less than 7 nm was formed. When the NP composite was further treated with NaOH solution followed by annealing at ambient conditions, a new nanocomposite material comprising Ag(2)S NPs on TiO(2) NWs was created. Due to the coupling with such a low bandgap material as Ag(2)S, the TiO(2) nanocomposites could have a visible-light absorption capability much higher than that of pure TiO(2). As a result, the synthesized Ag(2)S/TiO(2) nanocomposites exhibited much higher catalytic efficiency for the decomposition of methyl orange than commercial TiO(2) (Degussa P25, Germany) under visible light.