A novel three-dimensional porous Ag/TiO2 hybrid aerogels with high dense hot spot as effective SERS substrate for ultrasensitive detection

Xiangxin Xue; Cuimei Zhao; Yu Qiao; Ping Wang; Jing Wang; Jinghui Shi; Bo Liu; Zhuo Wang; Enhui Hou; Limin Chang; Jie Zhang

doi:10.1016/j.saa.2024.124849

A novel three-dimensional porous Ag/TiO₂ hybrid aerogels with high dense hot spot as effective SERS substrate for ultrasensitive detection

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Dec 5:322:124849. doi: 10.1016/j.saa.2024.124849. Epub 2024 Jul 19.

Authors

Xiangxin Xue¹, Cuimei Zhao², Yu Qiao², Ping Wang², Jing Wang², Jinghui Shi², Bo Liu³, Zhuo Wang², Enhui Hou², Limin Chang⁴, Jie Zhang⁵

Affiliations

¹ Key Laboratory of Preparation and Applications of Environmental Friendly Materials (Jilin Normal University), Ministry of Education, Changchun 130103, PR China; The Joint Laboratory of Intelligent Manufacturing of Energy and Environmental Materials, Changchun 130103, PR China. Electronic address: xuexiangxin0804@163.com.
² Key Laboratory of Preparation and Applications of Environmental Friendly Materials (Jilin Normal University), Ministry of Education, Changchun 130103, PR China.
³ Key Laboratory of Preparation and Applications of Environmental Friendly Materials (Jilin Normal University), Ministry of Education, Changchun 130103, PR China; The Joint Laboratory of Intelligent Manufacturing of Energy and Environmental Materials, Changchun 130103, PR China.
⁴ Key Laboratory of Preparation and Applications of Environmental Friendly Materials (Jilin Normal University), Ministry of Education, Changchun 130103, PR China. Electronic address: changlimin2139@163.com.
⁵ Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: jiezhang@ciac.ac.cn.

PMID: 39047668
DOI: 10.1016/j.saa.2024.124849

Abstract

This research focuses on preparing a series of new TiO₂/Ag hybrid aerogels with varying TiO₂ contents, and demonstrates their application as ultrasensitive SERS substrates. The synthesized TiO₂/Ag hybrid aerogels exhibited excellent SERS behavior when detecting 4-Mercaptobenzoic acid (4-MBA), and the calculated SERS enhancement factor (EF) was 6.34 × 10⁶. 3D structured aerogels can create more hot spots and adsorption sites, and multiple interband chemical transfer (CT) pathways emerged and enhanced CT efficiency because of the large number of surface oxygen vacancies of meso-TiO₂ NPs. Therefore, the synergy of electromagnetic field enhancement and chemical enhancement leads to SERS enhancement. In addition, the composite SERS substrate has high sensitivity, and the detection limit of adsorbed 4-MBA probe molecules reaches 10^-11 M. Furthermore, the TiO₂/Ag hybrid aerogels demonstrate good reproducibility with minimal standard deviation in terms of SERS signals. In addition, even after standing for 6 months, there is almost no attenuation in the SERS signal intensity, which highlights the excellent stability of this substrate. Therefore, these highly sensitive TiO₂/Ag hybrid aerogels SERS substrates have important practical value in environmental monitoring, medical inspection and food supervision.

Keywords: Aerogels; Ag; Mechanism; Reproducibility; SERS; Sensitivity; TiO(2).