| In this paper,three non-precious metal surface-enhanced Raman scattering（SERS）substrate materials,N-Ti O ultrathin porous nanosheets,Re ultrathin nanosheets and Re O3 self-assembled microtubes,respectively,were prepared by various synthetic methods,all of which have strong local plasmon resonance effects in the visible wavelength band,and they can achieve SERS detection under the combined effect of electromagnetic enhancement and chemical enhancement with detection effect comparable to that of precious metal substrates.The main elements are as follows:1.SERS flexible membranes with strong metallic properties and highly stable N-Ti O porous nanosheets were synthesized for the first time by a solvent thermal method combined with chemical vapor deposition and prepared by a simple filtration method.Taking advantage of the high similarity of Ti O and Ti N crystal structures,the disadvantages of conventional Ti O nanomaterials in terms of poor oxidation resistance and thermal stability were overcome by doping a small amount of nitrogen atoms in Ti O.The experiments show that the prepared N-Ti O nanosheets can be used for the highly sensitive detection of typical environmental contaminants such as2,4-dichlorophenol（2,4-DCP）and bisphenol A（BPA）,with detection limits of 10-11M and enhancement factors（EF）of 8.6×107.Meanwhile,the materials have good biocompatibility and low cytotoxicity,which are expected to be useful in the field of bioassay.2.A low-temperature molten salt method was developed to prepare high-quality multilayer Re nanosheets.These Re nanosheets can be self-assembled into large-size flexible films by lyophilization means,and a strong local SPR effect was observed in the visible region.The experimental results show that as a flexible substrate,this plasma film has high chemical stability and excellent SERS properties,and the specific surface area of this material reaches 173 m2·g-1,and the saturation adsorption capacities of R6G,methyl blue（MB）and methyl orange（MO）are 121 mg·g-1,82mg·g-1and 157 mg·g-1.This work provides important insights into the synthesis and application of Re metal 2D materials.3.Quasimetallic Re O3 self-assembled microtubes were grown using the polished surface of silicon wafers under high temperature and pressure by a simple solvent thermal reduction method.This microtubule structure itself is very rough and can adsorb more molecules of the test object,which makes Re O3 microtubules an efficient non-precious metal SERS substrate.The Raman enhancement factor（EF）of this substrate is as high as 8.9×105,and the detection limit of hazardous chemicals such as butylated hydroxyanisole（BHA）and 2,4-DCP can reach 10-9 M.It also has high corrosion resistance and low price,and these excellent properties lay a solid foundation for the application of Re O3 microtubes in analytical chemistry. |
