Self-assemble Of Au,Ag Superparticles/ZIF-8 Composite Materials And Applied To Sers Detection For VOCs

Nano-materials have unique optical, mechanical and magnetic properties, furthermore the self-assembly made of nanoparticles and these mutual coupling show more excellent physical and chemical properties than the bulk-materials and individual nano-materials. Au, Ag and other noble nanomaterials can significantly enhance the surface Raman scattering, which play a crucial role in trace detection of Raman. It is difficult that SERS achieves quantitative detection of gas in practical application and analytes adsorb on the materials surface at a low concentrate. In this paper we designed a high sensitivity three-dimensional SERS substrate skillfully, which can capture and achieve a specific detection for some specific lung cancer biomarker.First, The reaction conditions which contain the reaction solvent, reaction time, reaction temperature and the amount of reducing agent in the synthetic system were studied systematically in this paper. By controlling experimental conditions, the size controllable, monodisperse silver and gold nanoparticles were obtained, which can be taken as a element and excellent precursor to further prepare the noble assembly.Second, we studied the reaction conditions about the microemulsion-template method in preparation of the superparticles and obtained the gold superparticles with superlattices structure under optimized conditions. In order to realize effective enrichment for the gas detection, the core shell structure of Au SPs@ZIF-8 were obtain by denotative grown on the Au SPs and the thickness of the shell can be adjust by controlling the reaction conditions.Taking Rhodamine 6G (R6G) as the determinand in the actual SERS detection and electmagnetic field distribution simulation by FDTD solution proved that the ordered assembly show a more strength in SERS enhancement effect than disordered assembly, with nearly an order of magnitude improvement in R6G detection and the detection limit was down to 10-10mol·L-1. Au SPs@ZIF-8 modified with 4-Aminothiophenol self-assembled on a silicon wafer into a uniform thin film substrate and placed into atmosphere containing aldehydes with different concentration gradient to achieve molecular adsorption and capture, and use for SERS detect. The results show that the composite materials can achieve qualitative and quantitative detection for aldehydes, and the detection limit was down to lOppb. Furthermore the SERS signal has strong stability and good repeatability.