Surface-enhanced infrared absorption spectroscopy (SEIRA) of methanol, ethanol, 1-propanol, and 2-propanol in thin films on planar silver halide (AgX) fibers under slow N(2) flow using 1 sec scans reveals structure in absorbance-time plots. The absorption intensities show extra enhancements (3x) in the absorbance (O--H stretch) ascribed to oligomers present at the AgX surface (molecule enhanced, thus MOSEIRA). This is above those due to amplification (40x, 20 reflections) and enhancement (30x, image dipoles or surface phonon polaritons). In the case of ethanol an excellent initial pentamer spectrum evolves over 8-10 min to a mixture of pentamer, tetramer, and trimer spectra that within another minute forms small oligomers and monomers. We use a new type of cell for infrared spectroscopy containing an AgX planar fiber. The optical configuration leads to a vicinal region at the surface defined by evanescent waves. Within this region are surface-induced organized species such as ethanol oligomers. The planar AgX fiber supports 20 reflections and transmits light over a wide visible-infrared wavelength range. Short scan times permit the study of volatile substrates or solvents, including the effects of solvent polarity.
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http://dx.doi.org/10.1002/cphc.200700462 | DOI Listing |
Biosens Bioelectron
December 2024
National Research Council (CNR), Institute of Applied Sciences and Intelligent Systems, I-80131, Naples, Italy. Electronic address:
Spectrochemical analysis of trace elements in complex matrices is crucial across various fields of science, industry, and technology. However, this analysis is often hindered by background interference and the challenge of detecting ultralow analyte concentrations. Surface Enhanced Infrared Absorption (SEIRA) spectroscopy is emerging as a viable technique to address these challenges as it can successfully reveal soluble and unmodified analytes in a label-free manner through their interactions with a bioreceptor following site-specific labeling with small infrared-active probes.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany, 45470.
Molybdenum nitrogenase plays a crucial role in the biological nitrogen cycle by catalyzing the reduction of dinitrogen (N) to ammonia (NH) under ambient conditions. However, the underlying mechanisms of nitrogenase catalysis, including electron and proton transfer dynamics, remain only partially understood. In this study, we covalently attached molybdenum nitrogenase (MoFe) to gold electrodes and utilized surface-enhanced infrared absorption spectroscopy (SEIRA) coupled with electrochemistry techniques to investigate its catalytic mechanism.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
The controllable synthesis of epitaxial nanopillar arrays is fundamentally important to the development of advanced electrical and optical devices. However, this fascinating growth method has rarely been applied to the bottom-up synthesis of plasmonic nanostructure arrays (PNAs) with many broad, important, and promising applications in optical sensing, nonlinear optics, surface-enhanced spectroscopies, photothermal conversion, photochemistry, etc. Here, a one-step epitaxial approach to single-crystalline NbTiN (NbTiN) nanopillar arrays based on the layer plus island growth mode is demonstrated by strain engineering.
View Article and Find Full Text PDFACS Meas Sci Au
December 2024
State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Plasmon-enhanced infrared (IR) techniques have garnered significant interest for their ability to achieve greatly more sensitive IR detection than conventional surface enhanced IR techniques. However, the difficulty in electrically connecting antennas has limited their application in IR spectroelectrochemistry, a crucial field for catalysis, analysis, and energy storage. Recent technical advancements have enabled the successful application of electrochemical potentials to antennas, making plasmon-enhanced IR spectroelectrochemistry feasible.
View Article and Find Full Text PDFJ Agric Food Chem
December 2024
Department of Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China.
This study explores the development and application of gold and 4-mercaptopyridine (MPY) perovskite-engineered robust nanofibers (GLAMPER-NFs) for the ultrasensitive detection of Abscisic acid (ABA) under Raman spectroscopy, a crucial plant hormone. The GLAMPER-NFs composite material, consisting of MAPbCl nanofibers integrated with MPY-coated gold nanostructures, demonstrates exceptional performance in surface-enhanced Raman scattering (SERS)-based sensing. The study elucidates the material structure and properties through comprehensive characterization using scanning electron microscopy (SEM), UV-vis spectroscopy, fluorescence spectroscopy, Fourier transform infrared, and Raman spectroscopy.
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