L-cysteine-assisted Synthesis And Characterization Of Metal Sulfide Micromaterals

Accompanying with nanomaterial's further study, it has became important to synthesize materials with special morphologies, characters, and sizes by controlling the nucleation and growth progress. Until recently, different methods have been applied to synthesize nanomaterials. Now, it is a hot topic to apply biomolecule as template or assist agent to synthesize materials due to biomolecule's special structure and fascinating self-assembling functions. Their special properties make them templates of unmatched type for the design and synthesis of complicated structures.As a kind of useful materials, metal sulfides have been used widely in different field. Recently, most metal sulfides are synthesized by inorganic sulfur sources and metal cations. As one of life's basic building blocks, L-cysteine contains-SH in its molecule structure, which can act as sulfur source to synthesize metal sulfides. Besides, its molecule structure also contains the-NH2 and-COOH structure in average amino acid and can form peptide by condensation. How to use L-cysteine's special structure and self-assembling function for the synthesis of complicated structures has became a hot topic.In this thesis, a hydrothermal way was developed to synthesize several metal sulfide micromaterials. Various methods including X-ray powder diffraction (XRD), Transmission Electron Microscope (TEM), High-resolution Transmission Electron Microscope (HRTEM), Selected Area Electron Diffraction (SAED), Infrared Spectrum (IR) and Photoluminescence (PL) were used for characterization. The main summarized as follows.(1) Using L-cysteine as template, tube-likeγ-MnS microcrystals were synthesized under hydrothermal condition. Different phases and morphologies of MnS, such asαandγphase, thin flake like, sea urchin like, octahedral like, and capsule like, were synthesized by controlling reaction temperature, time, or adding certain surfactant. Photoluminescence experiments under room temperature have indicted that these pure MnS have good optical properties. (2) Based on above methods, different morphologies of NiS,Bi2S3 and other sulfides were prepared by changing pH values or adding chelating agent.The preparation method enriched and developed the technology of the preparation of metal sulfide micromaterials, whose size and morphology were enriched, besides, it also provides the theory supports of biomolecule assist synthesis of micro/nanomaterilas.