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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.

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.

Without any templates or surfactants, large-scale 3D persimmon-shaped hierarchical LaF3 and LaF3:Ln3+ (Ln = Eu, Tb) have been synthesized via a simple hydrothermal route using organic tetrafluroborate complexes N(C4H9)4BF4 as the fluoride source. The phase and morphology of the products have been characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The SEM and TEM results indicate the 3D persimmon-shaped hierarchical microstructures are constructed by numerous nanodisks with mean thickness of 50 nm. It is found that several factors, including the fluoride sources, molar ratio of reagents and the reaction time, play crucial roles in the formation of the multilayer stacked structures. Detailed studies indicate that the layer-by-layer self-assembly of nanodisks is responsible for the formation of 3D hierarchical structures. The possible mechanism of the crystal growth and assembled procedure are also proposed. Furthermore, the photoluminescent properties of LaF3:Ln3+ (Ln = Eu, Tb) are studied, which exhibit orange-red (Eu3+:5D0–7F1,2,3,4) and green (Tb3+, 5D4–7F3,4,5,6) emission, respectively.

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.