A superflexible hydrophobic silica-based aerogel (FHSA) was prepared via a facile sol−gel process and ambient pressure drying method. The FHSA was treated at different temperatures varying from −196 to 450 °C to evaluate its thermal and mechanical performances. The evolutions of the physical property, hydrophobicity, microstructure, pore structure, and chemical structure of the FHSA with the various treatment temperatures were investigated comprehensively. The structure of the FHSA did not show an obvious change after treatment in the liquid nitrogen. The bulk density of the FHSA increased from 0.047 to 0.077 g cm −3 when the thermal treatment temperature increased from 25 to 450 °C. The specific surface area and pore volume of the FHSA increased with the treatment temperature owing to the decomposition of the organic moieties. The Fourier transform infrared spectra showed that the methyl groups in the FHSA had excellent thermostability up to 400 °C. The water contact angles of the FHSA after treatment at

No abstract

Recent advances in surface‐enhanced Raman scattering (SERS) on semiconductor substrates offer this technology improved selectivity on top of other advantages, such as cost efficiency. However, the enhancement factor (EF) based on the semiconductors is still low compared with the noble metal substrates. Here, a new strategy of developing the semiconductor substrates based on aerogels is proposed for the first time. According to the modified Herzberg–Teller coupling rule, TiO2 aerogels are selected as the control object because of their large tunability. The surface area, amorphousness, and surface oxygen vacancy densities of TiO2 aerogels are regulated synergically. Due to the tuning of band structure, including band gap and defect band, multiresonant interband charge transfer (CT) pathways are generated and enhanced CT efficiency. A strong, intrinsically activated SERS effect is generated. Amorphous TiO2 aerogel with the highest surface oxygen vacancies shows a significant EF of 2.42 × 107, and TiO2 aerogels afford the large surface area and more active sites, which is conducive to promoting the adsorption of molecules. The aerogel‐based SERS is demonstrated to have wide applicability for ultrasensitive detection of explosives and organic dyes. The aerogel nanomaterials demonstrated here open a way for the construction of low‐cost and high‐sensitivity SERS substrate materials.

No abstract