三维SiO2-Ag多孔结构的制备及对挥发性有机物(VOCs)的SERS检测

Preparation of Three-Dimensional(3D)SiO2-Ag Porous Structure and SERS Detection of Volatile Organic Compounds(VOCs)

利用光化学还原法将Ag纳米粒子沉积到三维SiO2干凝胶中,制备了三维SiO2-Ag多孔复合结构基底。该材料具有大的比表面积、高孔隙率、表面具有高浓度的硅羟基(Si-OH),赋予了该材料优良的物理和化学吸附作用,实现了对VOCs的高效吸附和捕获能力。Ag纳米粒子的SERS增强作用,使得该基底高灵敏性地探测到了目标气体分子。该基底具有极佳的SERS信号均一性,以甲苯气体作为分析模型,随机20个点的主振动峰785 cm^-1、1002 cm^-1、1210 cm^-1的相对标准偏差值(RSD)分别为1.59%,1.40%和2.08%;基底稳定性测试表明,40天后的基底仍能保留77.68%的SERS活性;该基底对甲苯气体的检测浓度可低至187 ppm。此外,SiO2-Ag基底成功实现了对二种和三种混合气体的高灵敏探测。

Three-dimensional(3D)SiO2-Ag porous composite structure substrate was prepared by depositing Ag nanoparticles into 3D SiO2 xerogel via photochemical reduction method.The material has a large specific surface area,high porosity and a high concentration of silanol(Si-OH)on the surface,which endows the material excellent physical and chemical adsorption,resulting in efficient adsorption and capture of VOCs.The SERS enhancement of the Ag nanoparticles allows the substrate to detect target gas molecules with high sensitivity.The substrate has excellent SERS signal uniformity,take toluene gas detection as an example,the relative standard deviation values(RSD)of the main vibrational peaks of 785 cm^-1,1002 cm^-1 and 1210 cm^-1 at 20 spots are 1.59%,1.40%and 2.08%,respectively.The long-term stability test showed that the substrate still retained 77.68%SERS activity after 40 days.The substrate can detect toluene gas as low as 187 ppm.In addition,the SiO2-Ag substrate successfully achieved highly sensitive detection of two and three mixed gases.