Functionalised B‐Cu@F‐Ag@Au trimetallic nanomaterials with long term stability for rapid and highly sensitive in situ SERS detection of furfural in transformer oil

Abstract

The surface-enhanced Raman scattering (SERS) substrates enable a highly sensitive detection of furfural in the transformer oil. However, detection substrates with long-term stability are still extremely challenging. In this work, we anchored the thiol-containing coupling agents 2, 5-dimercapto-1, 3, 4-thiadiazole (DMTD) and 1, 4-benzenedithiol (BDT) on the surface of bubble copper (B-Cu) and flower-like silver nanoparticles (F-Ag), respectively. The three-dimensional SERS detection substrates with long-term stability by using a combination of chemical reduction and self-assembly methods were constructed. The substrate has a minimum detection limit of 10 −9 M for rhodamine B in oil with an enhancement factor of up to 2.23 � 10 7 . Importantly, the three-crystal B-Cu@F-Ag 1 @Au 5 substrate was used for the detection of furfural in the transformer oil with a detection limit of 2 mg/L and a relative standard deviation value of 2.46%. After 60 days of a simulated operation, the detection signal of furfural in the transformer oil samples at 75°C and still reached the initial value of 77.53%, indicating that the substrate has a good long-term stability. This triple frame structured SERS detection platform shows great potential in tracking furfural in the aging transformer oil mixing systems. | INTRODUCTIONPower transformers are the core equipment in the power transmission systems. During the actual operation of a transformer, its oil-paper insulation system is subjected to electrical, thermal and mechanical stress, and it produces aging characteristics [1][2][3][4]. As a typical aging characteristic, furfural can be used to accurately evaluate the aging degree of the transformer insulation system [5,6]. Chromatographic based spectrophotometry and high-performance liquid chromatography are routine detection methods for furfural in the transformer oil. These methods are expensive, and they are easily affected by the surrounding environmental factors and cannot complete the detection of a complex oil system [7,8]. To achieve a nondestructive and in situ detection of furfural dissolved in oil, Toshihiro et al. applied laser Raman spectroscopy to detect the standard sample of furfural in the transformer oil for the first time, and the minimum detection limit could reach only 104 mg/L [9], which cannot meet the furfural detection accuracy standard (4 mg/L) of the transformer oil after severe aging.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Ag–Au–Cu Trimetallic Alloy Microflower: A Highly Sensitive SERS Substrate for Detection of Low Raman Scattering Cross-Section Thiols

“…Similarly, trimetallic SERS substrates have also gained importance in recent years to complement the individual advantages of each SERS active material. For instance, trimetallic substrates such as Ag–Au–Cu nanostructures, − Au/Pt/Ag and Au/Pd/Pt colloidal nanocomposites, Au@Pd-Pt core shell NPs and nano cubes, , Ag–Au–Pt nano cages, Ag networks with Au-Pd NPs, Ag–Au–Pd NPs, trimetallic nano meshes were synthesized and used for various applications such as detection of important analytes including explosives, catalysis, and in situ chemical reaction monitoring. For all the above-mentioned reports, trimetallic structures provided superior SERS efficacy over the monometallic and bimetallic counterparts.…”