SERS Approach to Probe the Adsorption Process of Trace Volatile Benzaldehyde on Layered Double Hydroxide Material

Abstract

The study of the physicochemical process of volatile organic compound (VOC) adsorption on porous materials is significant for design and screening of adsorbent materials and treatment of VOCs. Traditional measurement methods for studying the adsorption process require lots of adsorbates and adsorbents and are time-consuming. We proposed a facile strategy to study the adsorption process of trace gaseous aldehydes on layered double hydroxide (LDH) using surface-enhanced Raman spectroscopy (SERS). We prepared a composite of Ag nanocubes@hollow Co–Ni LDH (AgNCs@Co–Ni LDH) with a strong adsorption capability and high SERS sensitivity. The adsorption properties of LDH for benzaldehyde in terms of general kinetics and isotherms were investigated. The kinetic adsorption process could be fitted better by the pseudo-first-order kinetics with a higher correlation coefficient than by the pseudo-second-order model, and the adsorption rate of 0.0308 min–1 was obtained from the fitting curve. The isotherm adsorption fits the Langmuir isotherm model, and its adsorption constant is 6.25 × 106 L/mol. Taking advantage of the excellent adsorptive performance and SERS activity, the AgNCs@Co–Ni LDH composite can be used as an effective SERS probe to detect gaseous aldehydes, and it shows a linear dynamic range (5–100 ppb) with a limit of detection reaching 1.83 ppb for benzaldehyde, better than that achieved by previous studies. Therefore, this work has not only established a new measurement method for probing the adsorption process with extremely low consumption of both adsorbates and adsorbents, but also may lay the groundwork for the construction of rapid and ultra-sensitive SERS sensors for probing VOCs in the future.

Additional Important Considerations in Surface-Enhanced Raman Scattering Enhancement Factor Measurements

“…It can be clearly seen that the characteristic SERS signal from the SERS substrate is gradually intensified and becomes constant with prolonged incubation (Figure ). An in-depth analysis reveals that the adsorption process follows the pseudo-second-order kinetic model: t / q t = t / q e + 1/( k · q e 2 ), − where q e and q t represent the SERS peak intensity at equilibrium time and given time t , respectively, and k is the pseudo-second-order rate constant.…”

Nanoporous Gold Stacked Layers as Substrates for SERS Detection in Liquids or Gases with Ultralow Detection Limits and Long-Term Stability

“…Considerable efforts have been devoted toward the fabrication of efficient SERS substrates, aiming to detect very low concentrations of molecules. A wide range of materials could be used as SERS substrates based on the aggregation of nanoparticles or metal nanostructures fabricated directly on solid substrates. ,,,− Particularly, metal nanoporous films have attracted much attention due to their remarkable morphology characterized by three-dimensional networks of interconnected ligaments at the nanoscale. − Their porosity gives them a high specific surface area to adsorb molecules and improve their performances as sensors. SERS sensitivity of these films could be attributed to the presence of hot spots located in nanogaps between ligaments.…”

Hybridizing Silver Nanoparticles in Hydrogel for High-Performance Flexible SERS Chips

“…Surface-enhanced Raman scattering (SERS) is a developing analytic technology that can amplify greatly the Raman spectral signals of analytes absorbed on some special substrate materials. , Because of the advantages, including quick response, rich fingerprint information, high sensitivity, wide detection range, and simple pretreatment, SERS analysis shows great application potential in many fields such as biological tissue, , food safety, − environmental detection, , drug analysis, and other fields. − However, there is still a certain distance for this novel sensing technology to wide spread, due to the limitations of the SERS substrate. In general, most of the current SERS substrates suffer from the following problems: (1) it is difficult to take into account both high sensitivity and long-term stability. ,, Fresh Ag nanostructures usually show much better SERS activities than Au nanomaterials. ,,, (2) The current SERS substrates are either in solid state or liquid state. , Usually, solid-state SERS substrates are much more popular than liquid-state SERS substrates because they are easier to operate.…”

“…Surface-enhanced Raman scattering (SERS) is a developing analytic technology that can amplify greatly the Raman spectral signals of analytes absorbed on some special substrate materials. 1,2 Because of the advantages, including quick response, rich fingerprint information, high sensitivity, wide detection range, and simple pretreatment, SERS analysis shows great application potential in many fields such as biological tissue, 3,4 food safety, 5−7 environmental detection, 8,9 drug analysis, and other fields. 10−12 However, there is still a certain distance for this novel sensing technology to wide spread, due to the limitations of the SERS substrate.…”