Preparation Of Germanate Nanomaterials And Their Properties

In rencent years, environmental pollution and fossil energy depletion have becoming increasingly serious issues, which call for urgent solution in the world. Photocatalysis can effectively and directly decompose the organic pollutant or produce hydrogen from water-splitting at mild temperature and pressure with solar energy and semiconductor photocatalysts. Photocatalysis gets great attention for its low energy consumption and environmental-friendly. Photocatalysis are dependent on the semiconductor photocatalysts and their microstructures including the morphology, size and pore structure have an important impact on the photocatalysi properties and recycle. Thus, the development of new and efficient photocatalysts has attracted great attention in recent years.In this work, we chose germanates as research object. We systematically studied the preparation of germanates nanomaterials and their photocatalytic properties. The main research works are as follow:1. Cd2Ge2O6 nanorods were prepared by the hydrothermal method, and subsequently prepared the CdS/Cd2Ge2O6 core-shell nanocomposites by in-situ ion exchange method. On the basis, we obtained the CdS hollow nanorods using lactic acid solution as sculpturer. The compositions, microstructures, light absorbance and specific surface area of the samples were characterized. Moreover, the photocatalytic H2 evolution of CdS hollow nanorods was systematically studied as a function of Pt-loaded amount, dosage of catalyst and concentration of lactic acid, respectively. The study found that the Pt-loaded CdS hollow nanorods is an excellent photocatalytic materials and the rate of H2 evolution can be up to 10.5 mmol·g-1·h-1 under the best conditions.2. Ag2ZnGeO4 flower-like hierarchical nanostocture composed by nanoplates and nanorods was successfully prepared by one-step water bath method. The compositions, element chemical state, microstructures and light absorbance of the samples were characterized. Meanwhile, we investigated the role of the dosage of AgNO3 and NH3·H2O for the formation of the Ag2ZnGeO4 flower-like hierarchical nanostructure. Moreover, the photocatalytic activity and photostability of Ag2ZnGeO4 flower-like hierarchical nanostocture was examined by the degradation of Rhodamine B (RhB). The study found that the as-prepared Ag2ZnGeO4 flower-like hierarchical nanostructure is an efficient and stable photocatalyst and the degradation of RhB is up to 92.5% under visible light irradiation.3. BiOI/Zn2GeO4 nanocomposites were prepared by a chemical bath approach. The compositions, element chemical state, microstructures and light absorbance of the samples were characterized. Meanwhile, the photocatalytic activities have been evaluated by photodegradation of p-nitrophenol (PNP). The BiOI/Zn2GeO4 nanocomposites showed much higher visible light photocatalytic activity compared to pure Zn2GeO4 and BiOI. Moreover, the photocatalytic activity of BiOI/Zn2GeO4 nanocomposites was studied as a function of BiOI amount, dosage of catalyst, concentration of PNP and solution pH, respectively. The study found that the 30 wt% BiOI/Zn2GeO4 composites exhibit excellent photocatalytic activity and the photodegradation of PNP reaches 47.6% under visible light irradiation.