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

Abstract

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.

Efficient SERS Response of Porous-ZnO-Covered Gold Nanoarray Chips to Trace Benzene–Volatile Organic Compounds

“…There have been some modification strategies developed for the SERS-based detection of different VOCs, mainly in two categories: the chemical specific adsorption strategies and physical structure capture strategies. For the former, some organic molecules, such as p -aminothiophenol (4-ATP) and 2,4-dinitrophenylhydrazine (2,4-DNPH), were used as modifiers of the plasmonic SERS substrates to specifically adsorb some VOCs, but the spectral patterns are the mixture of both the target molecules and modifiers and are difficult to distinguish. For the latter, some materials with porous structures, such as mesoporous SiO 2 , metal–organic framework (MOF), , layered double hydroxide (LDH), MXene, and oxide, were coated on the plasmonic SERS substrates to trap the gaseous VOC molecules, which has been proved to be the efficient method for VOCs’ capture.…”

SERS-Enabled Sensitive Detection of Plant Volatile Biomarker Methyl Salicylate

“…The SERS intensity and frequency of these probe molecules can be affected by other molecules which have chemical and/or physical interaction with them. Thus, they can be used to detect other molecules which do not have a large Raman cross section or strong interaction with the plasmonic structures. − In this work, we adopted this strategy and developed a SERS sensor for MeSA vapor detection. Specifically, 4-mercaptophenylboronic acid (MPBA) functionalized AuNPs were employed as the SERS probe.…”

Plasmon-Driven Interfacial Catalytic Reactions in Plasmonic MOF Nanoparticles

“…At present, a large number of studies have reported on plasmonic MOF nanoparticles, which consist of a noble metal nanoparticle core and an organic MOF nanoshell. Due to the unique optical properties and the porous organic MOF nanoshell, the excitation and coupling of surface plasmons at the noble metal nanoparticle–MOF interface are quite different from those of pure metal nanoparticle surfaces, which are studied in selective gas adsorption, separation, drug delivery, sensitive SERS detection, , etc. However, PDSC reactions in the plasmonic MOF interfaces have rarely been reported, and these reactions occur in a liquid-phase environment.…”