Study On The Controllable Preparation And Liquid Reduction Of Silver-Based Ternary Sulfides

In recent decades,as a new class of semiconductor nanomaterials,multimetallic sulfides have attracted more and more attention due to their special and tunable band structure and unique physical and chemical properties.They show promising applications in many fields,such as Photovoltaic devices,photoelectric catalysis,sensors,biomedicine,light-emitting devices,solar cells,thermoelectrics conversion.It’s well known that the materials’composition,structure,morphology and etc.have a significant impact on its performances.Therefore,to develop a simple,efficient,controllable and universal method is very essential for the preparation of materials.Meanwhile,in current research,It is still the focus of the research on the chalcogenide material to realize the precise control and synthesis of the morphology,band gap and components of materials and to explore the growth mechanism of the crystals.In this research,colloidal method have been developed to synthesis the materials,and we achieved a control synthesis of the morphology of ternary sulfide.The photocatalytic hydrogen evolution was studied.In addition,on the basis of the as-prepared sulfide,the intermetallic compound was prepared.Class compounds provide a new synthesis of ideas.This study provides a new synthetic strategy for the preparation of such compounds materials.The main contents of this thesis can be summarized as follows:（1）Based on the one-pot method of colloidal chemical synthesis,Ag-based ternary I₃-V-VI₃ semiconductor compound Ag₃SbS₃ nanocrystals with uniform size and high quality were prepared.By adjusting the reaction time,reaction temperature and ligand ratio,three kinds of nanocrystals with different morphologies were obtained,which were spherical,plate and prism,respectively,thus realizing the crystal morphology control.The phases,structures,morphologies,components and optical properties of as-prepared products were characterized and analyzed via X-ray powder diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,high resolution transmission electron microscope（HRTEM）,X-ray photoelectron spectroscopy（XPS）and UV-Vis absorption spectra of nanocrystalline.Because its energy band can meet the conditions that serve as the catalyst for photocatalytic hydrogen production,its photocatalytic properties were studied and we found that the crystal plane have a certain relationship with the hydrogen production performance.（2）Using the same method,the triangular pyramidal Ag₃SbS₃ nanocrystals were obtained by adjusting the ratio of the precursors and surfactants.The same hexagonal phase and space group R3c（161）were obtained.According to the properties that trialkylphosphine can selectively extracted part of S or Se from the chalcogenide compounds to form a low-component or more stable components,we conducted this experiment that as-prepared triangular pyramid Ag₃SbS₃ nanocrystals served as the parent precursor,and the chemical transformation reaction were achieved through adding different trialkylphosphine.Finally,Ag₃Sb phase was obtained.X-ray powder diffraction,scanning electron microscopy,transmission electron microscopy and photoelectron spectroscopy were used to characterize its crystal structure,morphology,size and composition.The results showed that it was the orthorhombic phase,and the rod-shaped Ag₃Sb was obtained by driving with tri-n-octylphosphine（TOP）.After reaction with tributylphosphine（TBP）and triphenylphosphine（TPP）,irregularly shaped Ag₃Sb have been also obtained.