Charge separation, protection of photocatalysts from hole attacks, and easy recyclability, which are of paramount importance in the development and applications of highly efficient and photochemically stable nanosized semiconductor photocatalysts, were achieved simultaneously by paramagnetic ZnFe2O4 nanocrystal decorated CdS nanorods. The photo-induced holes of CdS tend to migrate to the photochemically stable ZnFe2O4 domain while the photo-induced electrons of ZnFe2O4 tend to migrate to the photochemically more active CdS domain, achieving CdS protection and electron-hole separation. Decoration of ZnFe2O4 nanocrystals on CdS nanorod surfaces was achieved with a solvothermal process, giving a highly efficient, visible light responsive, photochemically stable, magnetically recyclable photocatalyst for hydrogen generation through water splitting. Specific hydrogen evolution rates as high as 2.44 mmol g(-1) h(-1) were achieved with the present product under visible light illumination, with its long term stability demonstrated.

Cu2O‐decorated mesoporous TiO2 beads (MTBs) are developed as a low‐cost, highly efficient photocatalyst for H2 production. MTBs with a high specific surface area of 189 m2 g−1, a large pore volume of 0.43 cm3 g−1 and a suitable pore size of 8.9 nm are decorated with band‐structure‐matched Cu2O nanocrystals through a simple, fast and low‐cost chemical bath deposition process. The Cu2O nanocrystals serve as an electron–hole separation centre to promote H2 evolution. Under optimal operation conditions, an ultra‐high specific H2 evolution rate of 223 mmol h−1 g−1 is achieved. The success is attributed to the structural advantages of the MTBs of high specific surface areas, large pore volumes and suitable pore sizes together with the much improved electron–hole separation and light utilisation of the Cu2O‐decorated MTBs. The H2 evolution rates achieved with the Cu2O‐decorated MTBs are one order of magnitude higher than those achieved by commercial P25 TiO2.

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This paper presents an investigation on the fluorescent properties of semiconductor CdTe quantum dots (QDs) self-assembled on the surface of PVP (polyvinylpyrrolidone)-capped silver nanoparticles (NPs) by the ligand field effect. A significant 2.5-fold enhancement in the integrated fluorescence intensities, red shift of fluorescence peak, and obvious decrease of lifetime were observed in the CdTe QDs assembled on the Ag NPs in comparison with the pure CdTe QDs. The fluorescence enhancement factor and red shift were found to depend on the Ag NP concentration. The fluorescence enhancement was attributed to a highly localized electromagnetic field on the Ag NPs generated by the surface plasma and the change in the surface trap state of the CdTe QDs originating from plasma oscillations in the Ag NPs. It is first proposed that the surface passivation of CdTe QDs is also an important factor for metal-enhanced fluorescence. The surface defects of CdTe QDs can be modified by the Cd-O coordination interaction between the CdTe QDs and PVP molecules, which will cause the trap state density and luminescence lifetime to decrease. The surface passivation of CdTe QDs can also improve fluorescence quantum yield and lead to the red shift of the fluorescence peak. Compared with previous reports, the occurrence of the self-assembly of CdTe QDs on the surface of PVP-capped Ag NPs is fairly simple and easy. From a practical point of view, the combination of CdTe QDs with Ag NPs may lead to the fluorescence enhancement, which could be utilized in a variety of chemical and biological detection applications.