In this paper, three-dimensional flower-like ZnO hierarchical nanostructures were fabricated from the thermal-decomposition of 3D zinc hydroxide carbonate precursor, which was synthesized by a urea hydrothermal method with block copolymer F127 (EO₁₀₆-PO₇₀-EO₁₀₆ ) as the morphology director. XRD, IR, UV-vis, SEM, TEM, TG and N₂ adsorption–desorption isotherms have been employed to characterize the products. The influences of synthesis parameters such as reaction time, the type of zinc sources, and species concentration on the morphologies of the products were systematically studied. It was found that the reaction time played a key role in determining the final morphology of porous ZnO. On the basis of experimental results, a possible formation mechanism of the 3D flower-like ZnO hierarchical nanostructures was discussed. More importantly, the gas sensing tests indicated that the sensor made from porous ZnO hierarchical nanostructures exhibited better gas sensing properties to n-butanol compared with the sensor based on the commercial ZnO nanoparticles. The enhancement in gas sensing properties was attributed to their unique 3D hierarchical nanostructures, high surface areas, and greater number of surface active sites.

TiO₂/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride and electron beam (EB) irradiation-pretreated graphene as the raw materials. The products were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of varying the synthesis parameters such as graphene content, concentration of titanium tetrafluoride solution and irradiation dose were investigated. It was found that the preparation conditions had a significant effect on the structure and properties of the final products. The irradiated graphene was covered with petal-like anatase TiO₂ nanoparticles, which were more uniform and smaller in size than those in products synthesized without EB irradiation-pretreated graphene. The photocatalytic activities of the products were evaluated using the photocatalytic degradation of methyl orange as a probe reaction. The results showed that the products synthesized using EB irradiation-pretreated graphene exhibited higher photocatalytic activities than those using graphene without EB irradiation pretreatment.

In this work, a novel type of hollow mesoporous silica nanoparticle (HMSN) with a rough surface has been successfully prepared via a facile soft–hard template route by using a carbon nanosphere as a hard template and cetyltrimethylammonium bromide (CTAB) as a soft template, respectively. This method involves the preparation of a carbon nanosphere, sequential coating of double SiO₂ layers, and the removal of the inner carbon core and CTAB to produce HMSNs. The obtained HMSNs possess spherical morphology, a mesoporous shell, and crumpled surfaces. The controlled experiments prove that the addition of 3-ammonia propyl triethoxy silane (APTES) is very crucial for the formation of desired HMSNs. The cell tests indicate that HMSNs show a good biocompatibility. As a result, the potential applications of HMSNs are further explored for drug delivery and protein adsorption, using doxorubicin hydrochloride (DOX) and Cytochrome c (Cyt c) as the model drug and protein, respectively. The HMSNs exhibit high drug loading and protein adsorption capacity, as well as the controlled pH-responsive release behavior for DOX. Therefore, the HMSNs prepared are ideal candidates for various applications such as nanoreactors, drug delivery and protein adsorption.

Chrysanthemum-like mesoporous silica nanoparticles (MSNs) with large surface areas were successfully synthesized in the presence of ethyl ether by a facile two-step method under mild conditions. Pyrene was chosen to evaluate their drug loading and controlled release properties. The results showed that prepared MSNs exhibited excellent release rate.

A facile solvothermal process combined with a precursor thermal transformation method has been developed for preparing porous TiO₂ hollow nanospheres with a high surface area and a good thermal stability. The porous TiO₂ hollow spheres were obtained by using TiOSO₄ as a titanium source and carbon nanospheres as a sacrificial template. Their particle size, diameter and morphology can be readily controlled by varying growth parameters, including reaction temperature, time and reagent concentration. The calcination temperature of TiO₂–C core-shell nanospheres was found to have a profound effect on the structure and properties of the final products. The photocatalytic activities of the products were evaluated by the photodegradation of methyl orange (MO). The TiO₂ hollow spheres obtained from 450 °C thermal treatment exhibited higher photocatalytic activity than commercial Degussa P25 in the presence of Cr(VI). The possible photodegradation mechanism was also investigated.