Hydrangea-like silver bromide/zinc oxide (AgBr/ZnO) photocatalysts were first synthesized using a one-pot, wet chemical method, and were composed of a ZnO hierarchical structure and AgBr nanoparticles (NPs). The as-synthesized AgBr/ZnO composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS) mapping analysis. The experimental results suggested that the AgBr NPs were uniformly decorated on the surface of the self-assembled ZnO hierarchical structure. It was found that poly vinyl pyrrolidone (PVP) and triethanolamine (TEOA) played important roles in the formation of the AgBr/ZnO hydrangea-like structure. The photocatalytic performance of AgBr/ZnO composites was then investigated using the degradation of rhodamine B under visible light irradiation. AgBr/ZnO composites exhibited better photocatalytic properties than pristine ZnO and AgBr, and the composite with 30% AgBr showed the best photocatalytic activity. The enhanced catalytic properties were attributed to the synergistic effects of the hierarchical hydrangea like structures, AgBr/ZnO heterojunction and metallic silver generated during the photocatalytic process. Therefore, the hydrangea-like AgBr/ZnO could act as a potential photocatalyst for environmental treatment and energy conversion.

Core–shell structured Au@Cu2O nanocomposites with different morphologies were prepared by a facile solution route. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results indicated that the obtained nanocomposite consisted of gold nanorod (NR) core and Cu2O shell, and both of them were in good crystallization. It was interested that the morphologies of the products could be tuned from octahedral to corner-truncated octahedral by changing the reductant. The results indicated that the reductant played a crucial role in determining the morphologies of as-prepared products. In addition, we investigated the photocatalytic properties of the products. It was found that both the core–shell structure and morphology of Au@Cu2O nanocomposites had great influence on the photodegradation of MO. As a result, the Au@Cu2O corner-truncated octahedral nanocomposites exhibited the best photocatalytic property. Our experimental results helped clarify the enhanced role of Au core and shape-dependent effect of Cu2O NPs, which contributed to pursue more efficient photocatalysts and other promising applications.

Pure TiO2 and C, N co-doped TiO2 (TiO2: C, N) nanoparticles were successfully synthesized by a modified sol–gel method, using urea as the carbon and nitrogen source. The entire preparation differs from the traditional sol–gel route employed to prepare nano-TiO2 for it does not require the use of any acid or alkali. The characterization results showed that as-prepared samples were nanoparticles with a diameter of 10–30 nm. Most of the carbon incorporated in the TiO2 matrix exists in the form of elemental carbon, and nitrogen was substituted for some of the lattice oxygen atoms. The PL spectra revealed that carbon and nitrogen dopants could enhance the separation of photo-excited electrons and holes, and improve the photo-catalytic efficiency of TiO2. The conjecture was demonstrated by degrading methyl blue under visible light, using the samples as the photo-catalyst.Highlights► TiO2: C, N nanoparticles were synthesized by a modified sol–gel method. ► The entire preparation does not require the use of any acid or alkali. ► As-prepared TiO2: C, N nanoparticles have a small and uniform size. ► As-prepared TiO2: C, N nanoparticles have an excellent visible-light photo-catalytic activity.

Hollow carbon nanospheres were prepared via a rapid detonation technique, by using negative-oxygen balance explosive trinitrotoluene and nickel powder as starting materials and inorganic acid as solvent. The carbon/metal nanocomposite particles precursor with core–shell structure was engendered firstly during detonation, and then the metal nickel core was dissolved through inorganic acid to attain the hollow carbon nanospheres. High-Resolution Transmission Electron Microscope, X-ray diffraction and Raman spectrum were used to characterize the precursor and the as-synthesized samples respectively. The results show that the external diameter of the hollow carbon nanospheres is 25–150 nm and the thickness of the wall is about 2–10 nm. The surface of hollow carbon nanosphere displays multilayer wall in structure with 0.35 nm space between the layers. Based on the experimental results, possible formation mechanism was also proposed.