Synthesis Of SERS Substrates And Their Application On The Detection Of Organic Pollutants

The 21th century witnesses the wide and rapid application of surface-enhanced Raman spectroscopy (SERS) in various fields, including analytical chemistry, life science, medical science, and the characterization of trace chemical species because of the clear advantages of SERS substrate, i.e., its high-performance SERS ability, providing fingerprint-like ingormation, without destroying the sample, and requiring little sample preparation. In this paper, multiple shaped noble metal nanoparticles were prepared with different methods, and the SERS of different shaped nanoparticles were studied. In addition, the optimum SERS-active substrates were used for detection of organic pollutants.In the first chapter, we review the development of SERS, generalize the preparation method of SERS substrates. In addition, we introduce the application of SERS.Chapter 2 mainly reports a transition of shape-selective silver nanostructures from nanoplates to nanodendrites, and to nanoclusters, which can be well controlled by changing the mole ratio of vitamin C to AgNO3. In addition, the formation of Ag nanostructures with multiple shapes can be well controlled depending on the efficient density-assisted self-assembly synthesis. The surface-enhanced effects of the formed Ag nanomaterials are strongly depending on the surface morphologies of Ag nanomaterials, and compared to the other as-presented Ag nanomaterials, the nanoclusters showed excellent surface-enhanced effects.In chapter 3, a multifunctional Au-coated TiO2 nanotube array is made via synthesis of TiO2 nanotube array through ZnO template, followed by depositions of Au particles onto the TiO2 surface using photocatalytic deposition and hydrothermal method, respectively. Such arrays exhibit superior detection sensitivity with high reproducibility and stability. In addition, possessing stable catalytic property, the arrays can clean themselves by photocatalytic degradation of target molecules adsorbed to the substrate under irradiation with UV light into inorganic small molecules after finishing per SERS detection, so that recycling can be achieved. Finally, by recyclable detection of dye Rhodamine 6G (R6G), herbicide 4-chlorophenol (4-CP), persistent organic pollutant dichlorophenoxyacetic acid (2,4-D), and organophosphate pesticide methyl-parathion (MP), the unique recyclable properties indicate a new route in eliminating the one-off jam of traditional SERS substrates and show its promising applications for detecting other organic pollutants. At the end of this paper, a short couclusion for the past work and the goal for future research are made.