Electrostatic Self-Assembly of Ti₃C₂T_x MXene and Gold Nanorods as an Efficient Surface-Enhanced Raman Scattering Platform for Reliable and High-Sensitivity Determination of Organic Pollutants

Abstract

A reliable surface-enhanced Raman scattering (SERS) substrate composed of two-dimensional (2D) MXene (Ti 3 C 2 T x ) nanosheets and gold nanorods (AuNRs) is designed and fabricated for sensitive detection of organic pollutants. The AuNRs are uniformly distributed on the surface of the 2D MXene nanosheets because of the strong electrostatic interactions, forming abundant SERS hot spots. The MXene/ AuNR SERS substrate exhibits high sensitivity and excellent reproducibility in the determination of common organic dyes such as rhodamine 6G, crystal violet, and malachite green. The detection limits are 1 × 10 −12 , 1 × 10 −12 , and 1 × 10 −10 M, and relative standard deviations determined from 13 areas on each sample are 18.1, 10.1, and 15.6%, respectively. In the determination of more complex organic pesticides and pollutants, the substrate also shows excellent sensitivity and quantitative detection, and the detection limits for thiram and diquat of 1 × 10 −10 and 1 × 10 −8 M, respectively, are much lower than the contaminant levels stipulated by the US Environmental Protection Agency. The MXene/AuNR composite constitutes an efficient SERS platform for reliable and high-sensitivity environmental analysis and food safety monitoring.

MXenes: Synthesis, Optical Properties, and Applications in Ultrafast Photonics

“…This nanocomposed substrate could also increase the detection limits for organic contaminants such as thiram and diquat to 1 × 10 −10 and 1 × 10 −8 m, respectively. [108] Therefore, MXenes with nano composites act as efficient SERS detection substrates in various applications including biomedical imaging, high sensitivity environmental analysis, and food safety monitoring.…”

The surface-enhanced resonance Raman scattering of dye molecules adsorbed on two-dimensional titanium carbide Ti3C2Tx (MXene) film

“…It has been reported that the Raman enhancement of dyes is solely dependent on the thickness of the MXene film, as well as the type of supporting substrate, like glass, Si or filter paper. [10][11][12][13]15,33 Previously, we have shown that SERS enhancement of the Ti 3 C 2 T x thin film on SiO 2 /Si exhibited a higher EF (5 Â 10 5 ; l 0 = 514 nm; EF based on both the EM and interband transition/ charge transfer (CT) mechanism of the enhancement) than those with a thicker and more uniform coating of Ti 3 C 2 T x film on SiO 2 / Si by spray-coating. 11 However, increasing the thickness of the Ti 3 C 2 T x film leads to a decreased SPR sensitivity as well as the Raman enhancement of dyes adsorbed on Ti 3 C 2 T x on the Si/SiO 2 substrate.…”

“…6,[10][11][12][13][14][15] The Raman enhancement mechanism from the monolayers of the 2D material is believed to be mainly CM. 2,5,16 It has been reported that another family of 2D materials, transition metal carbides and nitrides (MXenes) can be used as SERS substrates [10][11][12][13]15 and for other applications. [17][18][19] Both the structure and electronic properties of MXene-Ti 3 C 2 T x were largely affected by the functional groups on the MXenes where X = -F, -O and -OH.…”

Towards a Robotic Scientist for Synthesis of Nanocrystals

“…Retrosynthesis and optimization are the Robotic Scientist's creative endeavors. The data of the target Au nanocrystals (such as LSPR as 808 ± 10 nm, 780 ± 10 nm, and 633 ± 10 nm), which are commonly used in biotechnology and information technology (for example, HIV drug delivery 16 , surface-enhanced Raman scattering 17 , wireless neuromodulation 18 , and sensing 19,20 ), are extracted from the genome for further retrosynthesis study. Using 808 ± 10 nm as an example, 99 samples are selected from previous single-, double-, and three-factor experiments as shown in Fig.…”