Chen Qing-Qi, Hou Ruo-Nan, Zhu Yue-Zhou, Wang Xiao-Ting, Zhang Hua, Zhang Yue-Jiao, Zhang Lin, Tian Zhong-Qun, Li Jian-Feng
MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, College of Energy, College of Materials, Xiamen University, Xiamen 361005, China.
State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
Anal Chem. 2021 May 18;93(19):7188-7195. doi: 10.1021/acs.analchem.0c05432. Epub 2021 May 4.
Surface-enhanced Raman spectroscopy (SERS) is a promising ultrasensitive analysis technology due to outstanding molecular fingerprint identification. However, the measured molecules generally need to be adsorbed on a SERS substrate, which makes it difficult to detect weakly adsorbed molecules, for example, the volatile organic compound (VOC) molecules. Herein, we developed a kind of a SERS detection method for weak adsorption molecules with Au@ZIF-8 core-shell nanoparticles (NPs). The well-uniformed single- and multicore-shell NPs can be synthesized controllably, and the shell thickness of the ZIF-8 was able to be precisely controlled (from 3 to 50 nm) to adjust the distance and electromagnetic fields between metal nanoparticles. After analyzing the chemical and physical characterization, Au@ZIF-8 core-shell NPs were employed to detect VOC gas by SERS. In contrast with multicore or thicker-shell nanoparticles, Au@ZIF-8 with a shell thickness of 3 nm could efficiently probe various VOC gas molecules, such as toluene, ethylbenzene, and chlorobenzene. Besides, we were capable of observing the process of toluene gas adsorption and desorption using real-time SERS technology. As observed from the experimental results, this core-shell nanostructure has a promising prospect in diverse gas detection and is expected to be applied to the specific identification of intermediates in catalytic reactions.
表面增强拉曼光谱（SERS）由于出色的分子指纹识别能力，是一种很有前景的超灵敏分析技术。然而，被测分子通常需要吸附在SERS基底上，这使得检测弱吸附分子变得困难，例如挥发性有机化合物（VOC）分子。在此，我们开发了一种利用Au@ZIF-8核壳纳米粒子（NPs）检测弱吸附分子的SERS检测方法。可以可控地合成均匀的单芯和多芯壳纳米粒子，并且能够精确控制ZIF-8的壳厚度（从3到50纳米），以调节金属纳米粒子之间的距离和电磁场。在分析了化学和物理特性后，Au@ZIF-8核壳纳米粒子被用于通过SERS检测VOC气体。与多芯或厚壳纳米粒子相比，壳厚度为3纳米的Au@ZIF-8能够有效地探测各种VOC气体分子，如甲苯、乙苯和氯苯。此外，我们能够使用实时SERS技术观察甲苯气体的吸附和解吸过程。从实验结果可以看出，这种核壳纳米结构在多种气体检测方面具有广阔的前景，有望应用于催化反应中间体的特异性识别。
