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A simple one-step hydrothermal strategy has been developed to fabricate Sr2YF7 hierarchical microspheres employing NH4BF4 as fluoride source. The crystalline phase and morphologies of the products were characterized by XRD, TEM and SEM. The XRD results showed that the as-prepared samples were tetragonal phased Sr2YF7 with high crystallinity. SEM and TEM observation indicated that the as-synthesized hierarchical microspheres with average size of about 2 μm were assembled by hollow polyhedrons. N2 adsorption–desorption measurements revealed that the BET specific surface area of the typical Sr2YF7 hierarchical microspheres is up to 111.4 m2/g. The size and morphology of the products could be effectively controlled by adjusting the reaction times. Furthermore, the photoluminescence of hierarchical Sr2YF7:Eu3+ microspheres and hollow polyhedrons were measured, the result showed that PL intensity and decay time were sensitive to the morphology of the product.

ZnO/Ag composites were synthesized by photochemical deposition of Ag nanoparticles onto pre-synthesized three dimensional hierarchical cake-like ZnO microstructures, which were fabricated by DMF (N,N-dimethylformamide)-mediated solvothermal method. The crystal phase and microstructures of the as-obtained ZnO and ZnO/Ag were characterized by XRD, DRS, SEM, EDS, TEM and PL. The SEM and TEM results indicated that Ag nanodisks with diameters of 120 nm are uniformly deposited on the surface of hierarchical cake-like ZnO. Furthermore, the visible-light photocatalytic activity of the ZnO/Ag composites was evaluated by the degradation of Rhodamine B (RhB) under Xe lamp irradiation. Such ZnO/Ag composites showed an enhanced visible-light photocatalytic activity, the rate of degradation was nearly five times faster than that of bare hierarchical cake-like ZnO under visible-light irradiation due to the increase of electron-transfer rate of ZnO after hybridized with Ag nanoparticles.

A facile one-step solution-based method with the assistance of N,N-dimethylformamide (DMF) has been developed to prepare well-dispersed hierarchical flower-like ZnOHF nanostructures, in which DMF acts not only as solvent but also as surface-functionalizing agent. The prepared ZnOHF are characterized for the structural and morphological properties by XRD, SEM and TEM. The SEM and TEM results indicate that the hierarchical ZnOHF nanoflowers are assembled by numerous nanowires. The amount of DMF and reaction time play crucial roles in the formation of hierarchical nanowires-assembled ZnOHF nanoflowers. After calcination, the ZnOHF is completely transformed into ZnO while the flower structures are perfectly retained. The hierarchical ZnOHF and ZnO nanoflowers exhibit specific surface areas up to 48.8 m2/g and 71.2 m2/g, respectively. The as-obtained ZnOHF and ZnO nanoflowers exhibit excellent UV light photocatalytic activity for photodegradation of Rhodamine B.

Hierarchical YVO 4 microspheres have been prepared via L-aspartic acid (L-Asp) assisted hydrothermal route. X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to characterize the crystalline phase and morphologies of the products. The SEM results from different reaction stages indicate that YVO 4 microspheres are self-assembled by numerous nanowires with diameter of 30–50 nm. It is found that the amount of L-Asp and reaction time play crucial roles in the formation of hierarchical nanowires-assembled YVO 4 microspheres. The photocatalytic properties of YVO 4 were investigated by the decomposition of Rhodamine B (RhB) under UV light irradiation and exhibit good photocatalytic activities.

3D hierarchical flower-like Zn3(OH)2V2O7·2H2O microcrystals have been fabricated in a high yield via a simple hydrothermal process in the presence of l-aspartic acid (l-Asp). The purity, crystalline phase and morphologies of the products were characterized by XRD, TEM and SEM. The SEM results indicate that the microflowers are self-assembled by numerous nanobelts with mean diameter of 100 nm. During the process, l-Asp is chosen as the complexing and surface-functionalizing agent. It is found that the amount of l-Asp and reaction time have significant effects on the morphology of the Zn3(OH)2V2O7·2H2O micro/nanostructures. The photocatalytic properties of Zn3(OH)2V2O7·2H2O were investigated by the decomposition of RhB under UV light irradiation and exhibit good photocatalytic activities.

Uniform CaWO4:Tb3+ hollow microspheres with 3–4 μm diameter assembled by nanoparticles have been successfully fabricated via a simple hydrothermal route by using glycine as the structure directing agent. The glycine-assisted hydrothermal method is facile and effective in preparing CaWO4 hollow structures. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the crystalline phase and morphologies of the products. The effects of synthesis parameters on the morphologies of the as-prepared structures were investigated by SEM. It is found that the amount of glycine and reaction time all play crucial roles in the formation of CaWO4 hollow microspheres. The N2 adsorption–desorption and photoluminescent (PL) properties of the CaWO4:Tb3+ hollow microspheres were measured.

Employing NH4BF4 as the fluoride source, large scale fan-shaped ZnOHF hierarchical structures have been synthesized successfully with a template-free hydrothermal approach. The purity, crystalline phase, thermal stability and morphologies of the as-prepared ZnOHF were characterized by XRD, TG-DSC and SEM. Time-dependent experiments indicate that the hierarchical ZnOHF microfans are self-assembled by numerous nanotubes with diameter of 100 nm. A possible chemical mechanism is proposed. The as-prepared ZnOHF can be transformed into hexagonal phased netlike ZnO by calcination in air at 600 °C. Furthermore, the as-prepared ZnOHF and ZnO were investigated by the decomposition of methylene orange under UV light irradiation and the results show that they have good photocatalytic activities.

At room temperature, a simple solution-based procedure employing NaBF 4 as the fluoride source has been developed to selectively prepare different morphological TbF 3 nano/microcrystals (disks, peanuts and spindles) with an orthorhombic structure. The crystal structure, morphology and photoluminescence properties of the as-prepared TbF 3 crystals were investigated by x-ray powder diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The results revealed that large-scale and uniform disks with a mean thickness of 20 nm can be easily synthesized, and the spindle-like and peanut-like TbF 3 crystals were assembled from nanodisks. The effects of synthesis parameters such as NaBF 4 , reaction time and molar ratio of the reactants were systematically investigated. The room temperature PL properties of these different morphological TbF 3 microcrystals were measured.

Employing N(C 4 H 9 ) 4 BF 4 as fluoride source, large scale multilayer-stacked hierarchical persimmon-shaped CeF 3 architectures have been prepared via a facile and template-free hydrothermal route. The crystalline phase and morphology of the as-prepared hierarchical CeF 3 microcrystals were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results revealed that uniform and monodispersed hierarchical nanodisk-assembled persimmon-shaped CeF 3 microcrystals with average diameters of 3 μm can be easily synthesized. The effects of synthesis parameters, as well as fluoride source and reaction time were systematically investigated. The room temperature photoluminescence (PL) properties of these different morphological CeF 3 :Tb 3+ were measured.