Pt@SiO2@TiO2 composites with an average diameter of about 120 nm were synthesized by an aqueous method. Morphology, microstructure, and light absorption performance of as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV–Vis diffuse reflectance spectroscopy. The results indicate that 5-nm-thick SiO2 interlayer coated on the Pt nanoparticles were used to separate the Pt from the TiO2. The covering SiO2 layer between Pt nanoparticles and TiO2 layer present a wide spectral response. The enhanced photocatalytic efficiency under both the full spectrum and visible light can be attributed to the existence of Pt nanoparticles and interlayer SiO2. The coupling processes between TiO2 and plasmon were presented and the mechanism was discussed. The localized surface plasmon resonance effect of Pt nanoparticles is the main reason for the enhanced photocatalytic activity of the composite Pt@SiO2@TiO2.

Si/TiO2 heterojunction photocatalyst was synthesized via a facile hydrothermal reaction and exhibits high photocatalytic activity towards conversion of CO2 to methanol.

Cu2O/TiO2 composite nanotube arrays demonstrating enhanced photocatalytic performance were synthesized using an electrodeposition method to impregnate the p-type Cu2O into the n-type titanium dioxide nanotube arrays (TNTs). The morphological results confirmed that the TNTs are wrapped by the Cu2O nanoparticles and the UV–Vis absorption spectra showed that the Cu2O/TNTs display a better ability for visible light absorption compared to the pure TNTs. CO2 photocatalytic reduction experiments carried out by using Cu2O/TNT nanocomposites proved that Cu2O/TNTs exhibit high photocatalytic activity in conversion of CO2 to methanol, while pure TNT arrays were almost inactive. Furthermore, Cu2O/TNTs also exhibited augmented activity in degradation of target organic pollutant like acid orange (AO) under visible light irradiation. The ultra enhanced photocatalytic activity noticed by using Cu2O/TNTs in CO2 reduction and degradation of organic pollutant could be attributed to the formation of Cu2O/TiO2 heterostructures with higher charge separation efficiency.

CdS hollow nanospheres with enhanced photocatalytic performance have been prepared by employing SiO2 nanospheres as templates with a simple and mild solution reaction at room temperature. Field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) analyses confirmed that these CdS hollow nanospheres possess 370 nm diameter and the wall thickness less than about 30 nm. UV-Vis absorption spectra show that the as-synthesized hollow CdS nanospheres display better light absorption ability than the contracted solid CdS nanospheres. Furthermore, the hollow CdS nanospheres exhibit enhanced activity toward decomposition of target organic pollutant such as Rhodamine B (RhB), under Xe arc lamp irradiation. The calculated rate constants for hollow CdS nanospheres are 5.5 times larger than that of solid CdS nanospheres, which could be ascribed to the improved light absorption ability, adsorption capability due to the hollow structure, and higher charge separation efficiency achieved by shortening the charge transporting path with thinner hollow CdS shell.

In the current study, monocrystalline silicon nanowire arrays (SiNWs) were prepared through a metal-assisted chemical etching method of silicon wafers in an etching solution composed of HF and H2O2. Photoelectric properties of the monocrystalline SiNWs are improved greatly with the formation of the nanostructure on the silicon wafers. By controlling the hydrogen peroxide concentration in the etching solution, SiNWs with different morphologies and surface characteristics are obtained. A reasonable mechanism of the etching process was proposed. Photocatalytic experiment shows that SiNWs prepared by 20% H2O2 etching solution exhibit the best activity in the decomposition of the target organic pollutant, Rhodamine B (RhB), under Xe arc lamp irradiation for its appropriate Si nanowire density with the effect of Si content and contact area of photocatalyst and RhB optimized.