Controllable synthesis of CuS nanostructures from self-assembled precursors with biomolecule assistance

In this work, taking the preparation of CuS nanomaterials as an example, the multiple roles of L-cysteine in the formation of metal sulfide nanostructures were elucidated. First, the precursors captured from the initial reaction solutions were characterized by X-ray diffraction, X- ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy, which indicated that three typical precursors with different morphologies (dispersive flakes, flake-built spherical aggregations, and solid microspheres) have formed in the three initial reaction solutions with different ratios of L-cysteine to CuCl2, 2H(2)O. Then, the as-formed precursors decomposed as self-sacrificed templates under the hydrothermal condition to produce the interesting CuS nanostructures of highly ordered nanostructures (snowflake-like patterns and flower-like microspheres) and porous hollow microspheres. The mechanisms for the formation of the precursors and their transformation to the final CuS nanostructures have been discussed in detail. The UV-vis diffuse reflectance spectra of the as-obtained CuS nanomaterials with different morphologies have been investigated and discussed. Such work is meaningful in understanding the self-assembly of nanostructures and helpful to prepare novel functional nanomaterials.