Au@ZIF‑8 Core–Shell Nanoparticles as a SERS Substrate for Volatile Organic Compound Gas Detection

• Published in: Analytical chemistry (Washington) Vol. 93; no. 19; pp. 7188 - 7195
• Main Authors: 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
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18-05-2021
• Subjects: Adsorption; Analytical chemistry; Chemical fingerprinting; Chemistry; Chlorobenzene; Core-shell particles; Core-shell structure; Electromagnetic fields; Ethylbenzene; Gold; Intermediates; Nanoparticles; Organic compounds; Raman spectroscopy; Shells; Stability; Substrates; Technology assessment; Thickness; Toluene; VOCs; Volatile organic compounds
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.0c05432

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.