Hydroxyl Group-Abundant TiO₂ Semiconductor SERS Sensor toward Polymerization Inhibitor Sensing

Abstract

One of the most significant challenges faced by semiconductor-based surface-enhanced Raman scattering (SERS) is achieving high-efficiency SERS detection in complex real-world application scenarios. Currently, the analytical applications of semiconductor-based SERS in a practical system inevitably encounter significant difficulties because of the lack of highly efficient charge-transfer (CT) in common semiconductor systems. Here, we present the sensitive detection of trace polymerization inhibitors in olefins using colloidal TiO 2 nanocrystals as SERS substrates within minutes, which has important implications for olefin quality monitoring. The detection relies on the formation of a resonance-related CT complex between polymerization inhibitors and colloidal TiO 2 , resulting in highly efficient CT. As such, this method offers detection limits as low as 0.9 ppm, which is sensitive enough to enable assessment of polymerization inhibitors in commercial olefin products. We envision that this approach will be of great utility for producing and storing high-quality olefins and other important chemicals.

Defect engineering in semiconductor-based SERS

“…In environmental analysis, the detection of small ionic species such as Cr (VI) and PO4 3in water samples have been achieved with colloidal TiO2 nanoparticles with rich surface hydroxyl groups 108,109 . Hydroxyl-group-rich TiO2 colloids are also especially selective towards phenolic molecules, and have been proposed as SERS sensor for quantitative analysis of phenolic polymer inhibitors in olefins 97 . In food analysis, methods for the detection of prohibited substances are in high demand.…”

“…Titanium oxide nanostructures have also been a prototypical subject of study for surface tuning due to their well-known affinity towards multiple functional groups. It has been pointed out that dangling oxygen species (Ti-O) formed in small TiO 2 nanoparticles and their hydrogenated form can be highly active towards phenolic molecules such as dopamine, catechol and hydroquinone, both as binding sites and to facilitate CT. [95][96][97] Based on this, Lewis and Brønsted surface sites can be produced as a result of defect-tuning. Gong et al 98 showed that with the substitution of SO 6b).…”

“… 108,109 Hydroxyl-group-rich TiO 2 colloids are also especially selective towards phenolic molecules, and have been proposed as SERS sensors for quantitative analysis of phenolic polymer inhibitors in olefins. 97 In food analysis, methods for the detection of prohibited substances are in high demand. Recently, a SERS-chip for detection of Sudan Red III in Chinese medicinal herbs was developed using defective Cu 2 O nanostructures ( Fig.…”

Defective cuprous oxide as a selective surface‐enhanced Raman scattering sensor of dye adulteration in Chinese herbal medicines

“…After this simple sampling, the Raman spectra were collected from the center of the dried film using a 785-nm laser as the excitation source. Figure 3a shows the Raman spectra of the SR3 analyte at a concentration of 10 À4 M when mixed with Cu 2 O nanocubes, W 18 O 49 [8] nanowires, TiO 2 [34] nanospheres, commercially available colloidal Au nanoparticles, Ag nanoparticles and Q-SERS chips, respectively. The concentrations of nanoparticle substrates in the mixture are all set to be 1 mg/ml.…”

Experimental and theoretical evaluation of crystal facet exposure on the charge transfer and SERS activity of ZnO films

“…5–8 As a consequence, semiconductors, with advantages of low cost, good stability and biocompatibility, have emerged as an alternative to noble metals and received extensive research interest. At present, a series of semiconductors has been revealed to exhibit Raman enhancement, including V 2 O 5 , 9 TiO 2 , 10 K 2 Ti 6 O 13 , 11 W 18 O 49 , 12–14 ZnO, 15 Cu 2 O, 16 Ta 2 O 5 , 17 etc . In particular, ZnO is endowed with a tunable band gap and carrier properties, such as wavelength dependence and barrier confinement through introducing impurities and surface functionalities, which are expected to effectively regulate charge transfer and SERS activity.…”