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Many studies have shown that it is important to consider the harmful effects of phenolic hormones on the human body. Traditional UV detection has many limitations, so there is a need to develop new detection methods. We demonstrated a simple and rapid surface-enhanced resonance Raman scattering (SERRS) based detection method of trace amounts of phenolic estrogen. As a result of the coupling reaction, there is the formation of strong SERRS activity of azo compound. Therefore, the detection limits are as low as 0.2 × 10−4 for estrone (E1), estriol (E3), and bisphenol A (BPA). This method is universal because each SERRS fingerprint of the azo dyes a specific hormone. The use of this method is applicable for the testing of phenolic hormones through coupling reactions, and the investigation of other phenolic molecules. Therefore, this new method can be used for efficient detection. [ABSTRACT FROM AUTHOR]

We employ a facile and novel route to synthesize multifunctional Ag-Cu2O nanocomposite films through the self-assembly of nanoparticles at an air-liquid interface. In the ethanol-water phase, AgNO3 and Cu(NO3)2 were reduced to Ag-Cu2O nanoparticles by NaBH4 in the presence of cinnamic acid. The Ag-Cu2O nanoparticles were immediately trapped at the air-liquid interface to form two-dimensional nanocomposite films after the reduction reaction was finished. The morphology of the nanocomposite films could be controlled by the systematic regulation of experimental parameters. It was found that the prepared nanocomposite films serving as the substrates exhibited strong surface-enhanced Raman scattering (SERS) activity. 4-aminothiophenol (4-ATP) molecules were used as the test probes to examine the SERS sensitivity of the nanocomposite films. Moreover, the nanocomposite films synthesized by our method showed enhanced electrocatalytic activity towards hydrogen peroxide (H2O2) and therefore could be utilized to fabricate a non-enzymatic electrochemical H2O2 sensor. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple in-situ reducing method was used for the Ag-MXene composites fabrication. • The SERS signal was enhanced by the synergistic effect of chemical and physical mechanisms. • The Ag-MXene composite provide higher enhancement factor for SERS-based application. MXene sheets with the unique electrical and optical properties show the excellent potential for surface-enhanced Raman spectroscopy (SERS) applications. In this study, we chose Ti 3 C 2 T x , a type of MXene, to decorate silver nanoparticles (Ag NPs) on the ultrathin two-dimensional (2D) MXene sheets. The designed Ag-MXene substrates with SERS activity showed high sensitivity, high stability, and reproducibility. The SERS signal was enhanced by the synergistic contribution of both charge-transfer (CT) and surface plasmon resonance (SPR) involving the Ag NPs and the MXene sheets. Due to the strong interaction between the probe molecules and Ag NPs which provided the nanoscale gap, the substrate exhibited remarkable SERS performance. A novel experimental strategy was developed to facilitate the controlled synthesis of noble metal NPs and MXene sheets and provide insights for further improving the practical applications of these materials in SERS detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ag/4-MBA/PAN nanocomposite was designed and exhibited an excellent surface-enhanced Raman scattering (SERS) activity. • The degree of charge transfer (CT) has a positive correlation with the PAN thickness. • The CT direction in the nanocomposite system was successfully verified by 2D correlation spectroscopy (2D-COS). The purpose of this paper is to study the charge transfer (CT) process of a Ag/MBA/PAN system with different thicknesses of PAN and explore its SERS enhancement mechanism. It is found that as the PAN thickness is increased, the frequency and intensity of the characteristic MBA band gradually increases. The intensity of the b 2 mode increases significantly, which is attributed to the CT mechanism. As the PAN thickness is increased, the degree of CT (ρ CT) gradually increases, which is due to the excited SPR from Ag. The electromagnetic enhancement mechanism, which occurs at the interface between PAN and Ag, generates hot electrons and rearranges the interface between PAN and Ag, thereby promoting electron transfer for the whole CT in Ag/MBA/PAN. These results show that CT occurs from the Fermi level of Ag to the LUMO level of MBA and then to the LUMO level of PAN. Additionally, the direction of CT is verified by 2D-COS. Therefore, this study not only reveals the ultrahigh SERS activity of the substrate but also explains the detailed process of regulating the substrate through the PAN thickness, which affects the SERS mechanism. This conductive polymer will open up a new horizon of SERS research and applications. [ABSTRACT FROM AUTHOR]