Synthesis Of Core-Shell Structured Ce₂S₃@ZnO And TiO₂@PDA And Their Potentials As Pigment And Photocatalyst

Core-shell structured nanomaterials are of great importance in multitudes of areas including energy, biomedicine, catalysis and environment, etc. due to their unique physicochemical, electrochemical, photochemical properties and their catalytic and chemical stabilities.In this thesis, two easy-realized methods, namely, direct precipitation and in-situ polymerization, were used to construct core-shell functional materials with hexamethylenetetramine (HMTA) to provide the optimum weak alkaline condition. Meanwhile, we systematically discussed their potentials as nontoxic pigment and photocatalyst. First, the Ce2S3@ZnO was prepared by using ascorbic acid (AA) which can interact with Zn2+ to form a Zn2+-AA complex, without which a uniform ZnO coating cannot be obtained. The Ce2S3@ZnO was then successfully synthesized after 3 hours’ reaction at 90 ℃ in the presence of hexamethylenetetramine (HMTA) as the precipitator. The core-shell structured pigment further showed remarkable performances on H2S adsorption and thermal stability. Second, based on the understanding of the in-situ polymerization of dopamine, a very thin polydopamine (PDA) coating (1 nm) was successfully introduced onto the surface of anatase TiO2 nanoparticles (average diameter of 30 nm). Typically, HMTA was chosen to provide an optimum alkaline environment for the construction of TiO2@PDA. We explored the photocatalytic activity of TiO2@PDA by degrading Rhodamine B (RhB) under visible light radiation. The specific interaction between PDA and TiO2 successfully enhanced the visible-light photocatalytic activity with an entire degradation of RhB in 90 min.The synthesized materials were characterized by TEM, SEM, XRD, FTIR and TG-DTG techniques. The effects of precursor, ligand, surfactant, precipitant, and temperature on the morphology and performance of the materials were also investigated.