表面增强拉曼光谱(SERS)是一种有前途的高灵敏度分子指纹检测技术。然而,开发无标签的SERS纳米复合材料,高度敏感,选择性,稳定,和可重复使用的气态挥发性有机化合物(VOCs)检测仍然是一个挑战。这里,我们报道了一种新型TiO2NTs/AuNPs@ZIF-8纳米复合材料,用于VOCs的超灵敏SERS检测。具有较大比表面积的三维TiO2纳米管结构为AuNP的负载提供了丰富的位点,具有优异的局部表面等离子体共振(LSPR)效应,进一步导致形成大量的SERS活跃热点。外部包裹的多孔MOF结构将更多的气态VOC分子吸附到贵金属表面上。在物理和化学增强的协同机制下,可以获得更好的SERS增强效果。通过优化实验条件,苯乙酮的SERS检测限,常见的呼出的VOC,低至10-11M。并且来自同一纳米复合材料表面上不同点的SERS信号强度的相对标准偏差为4.7%。苯乙酮气体达到1分钟的响应,信号在4分钟内达到稳定。在紫外线照射下,表面吸附的苯乙酮可以在40分钟内完全降解。实验结果表明,该纳米复合材料具有良好的检测灵敏度,重复性,选择性,响应速度,和可重用性,使其成为有前途的气体挥发性有机化合物的传感器。
Surface-enhanced Raman spectroscopy (SERS) is a promising and highly sensitive molecular fingerprint detection technology. However, the development of SERS nanocomposites that are label-free, highly sensitive, selective, stable, and reusable for gaseous volatile organic compounds (VOCs) detection remains a challenge. Here, we report a novel TiO2NTs/AuNPs@ZIF-8
nanocomposite for the ultrasensitive SERS detection of VOCs. The three-dimensional TiO2 nanotube structure with a large specific surface area provides abundant sites for the loading of Au NPs, which possess excellent local surface plasmon resonance (LSPR) effects, further leading to the formation of a large number of SERS active hotspots. The externally wrapped porous MOF structure adsorbs more gaseous VOC molecules onto the noble metal surface. Under the synergistic mechanism of physical and chemical enhancement, a better SERS enhancement effect can be achieved. By optimizing experimental conditions, the SERS detection limit for acetophenone, a common exhaled VOC, is as low as 10-11 M. And the relative standard deviation of SERS signal intensity from different points on the same
nanocomposite surface is 4.7%. The acetophenone gas achieves a 1 min response and the signal reaches stability in 4 min. Under UV irradiation, the surface-adsorbed acetophenone can be completely degraded within 40 min. The experimental results demonstrate that this
nanocomposite has good detection sensitivity, repeatability, selectivity, response speed, and reusability, making it a promising sensor for gaseous VOCs.