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Surface‐enhanced infrared absorption (SEIRA) spectroscopy has emerged as a powerful technique, amplifying inherently weak molecular vibration signatures to enable ultrasensitive detection of molecular structure and dynamics. However, conventional SEIRA platforms based on noble metals or 2D materials are fundamentally constrained by their narrow spectral bandwidths and limited access to high‐frequency vibrational modes. Here, we demonstrate an ultrabroadband SEIRA approach that overcomes these limitations by activating acoustic plasmon modes in two‐dimensional Ti3C2Tx MXene. These acoustic plasmons provide deep subwavelength confinement, compressing wavelengths by more than two orders of magnitude relative to free space in the short‐wave infrared (SWIR), and sustaining an unprecedented spectral bandwidth of approximately 5000 cm–1. Using this platform, we achieve simultaneous detection of distinct vibrational fingerprints—from high‐frequency CH3 combination bands near 4700 cm−1 to low‐frequency out‐of‐plane bending modes around 700 cm−1—in ultrathin analytes such as 8 nm PMMA and 10 nm graphene oxide films, with up to an order‐of‐magnitude sensitivity enhancement. These results establish acoustic plasmon modes in MXene as a transformative foundation for ultrabroadband, high‐sensitivity deep‐infrared spectroscopy, paving the way for next‐generation molecular sensing technologies. Acoustic plasmons in Ti3C2Tx MXene strongly compress infrared electromagnetic fields and enhance light–matter interactions at the nanoscale. This platform couples broadband plasmon excitations with molecular vibrations, enabling simultaneous sensing of high‐ and low‐frequency vibrational modes in ultrathin PMMA and graphene oxide films, and extending SEIRA functionality far beyond conventional narrowband limits.

The work presents a comprehensive vibrational analysis of the process of adsorption of threonine (Thr) onto an Fe surface with deposited Cu nanoparticles (NPs) (of about 4–5 nm in size) in a corrosive environment. The application of surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared absorption spectroscopy (SEIRA) provides the opportunity for detailed description of adsorption geometry of amino acid onto a metal surface. The combination of conventional infrared spectroscopy (IR) with atomic force microscopy (AFM) resulted in a nano-SEIRA technique which made it possible to provide a precise description of adsorbate binding to the metal surface. The studies presented confirmed that there is a very good correlation between the spectra recorded by the SERS, SEIRA, and nano-SEIRA techniques. Threonine significantly influenced the process of corrosion of the investigated surface due to the existing strong interaction between the protonated amine and carboxylate groups and the CuNPs deposited onto the Fe surface. In addition, the application of two polarization modulations (s and p) in nano-SEIRA allows subtle changes to be observed in the molecule geometry upon adsorption, with the carboxylate group of Thr being almost horizontally oriented onto the metal surface; whereas the amine group that contains nitrogen is oriented perpendicular to this surface.

The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction (HER). Here, we synthesized a composite catalyst of Cu and Mo 2 C (Cu/Mo 2 C) using Anderson-type polyoxometalates (POMs) synthesized by the facile soaking method as precursors. The electronic interaction between Cu and Mo 2 C drives the positive charge of Cu, alleviating the strong adsorption of hydrogen at the Mo site by modulating the d-band center of Mo 2 C. By studying the interfacial water structure using in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), we determined that the positively charged Cu crystals have the function of activating water molecules and optimizing the interfacial water structure. The interfacial water of Cu/Mo 2 C contains a large amount of free water, which could facilitate the transport of reaction intermediates. Due to activated water molecules and optimized interfacial water structure and hydrogen adsorption energy, the overpotential of Cu/Mo 2 C is 24 mV at a current density of 10 mA·cm −2 and 178 mV at a current density of 1000 mA·cm −2 . This work improves catalyst performance in terms of interfacial water structure optimization and deepens the understanding of water-mediated catalysis.

Through interface engineering and content control strategy, a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO 2 to formate with a remarkably high Faraday efficiency (FE formate ) of 94% and a partial current density ( j formate ) of 34 mA·cm − 2 at −0.8 V vs. reversible hydrogen electrode (RHE) in an H-cell. Moreover, the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm − 2 with formate selectivity up to 92% in a flow cell and could steadily operate for at least 20 h. Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) confirmed that the PdBi interface could greatly weaken the adsorption of *CO intermediates due to electronic and geometric effects. Density functional theory (DFT) calculations also established that the PdBi interface regulated the CO 2 -to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of *CO intermediates on the catalyst surface. This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations.

We apply surface-enhanced infrared absorption (SEIRA) spectroscopy to monitor the denaturation process of a surface-bound protein A monolayer. Our proposed platform relies on a plasmonic metasurface comprising different spatial subregions (“pixels”) that are engineered to exhibit different resonances covering the infrared region of the electromagnetic spectrum that is matched to the vibrational modes of the Amide groups. Specifically, we are able to determine changes in the Amide I and Amide II vibration coupled modes, by comparing the SEIRA reflectance spectra pertaining to the native state and a denatured state induced by a pH variation. In particular, we observe some evident red-shifts in the principal Amide I mode and the Amide II vibration coupled modes (attributable to the breaking of hydrogen bonds), which result in insurmountable barriers for refolding. Thanks to the strong field localization, and consequent enhancement of the light-matter interactions, our proposed sensing platform can operate with extremely small amounts of an analyte, with an estimated detection limit of about 3 femtomoles of molecules.

In this study, carbon nanodots (CNDs) with excellent aqueous dispersibility, narrow size distribution, and oxygen-rich functional groups have been prepared via a green electrochemical method. Graphite electrodes were directly electrolyzed at ambient temperatures to form uniform CNDs in deionized water, which is free from additional oxidant/reductant. As-synthesized CNDs have been applied to coat an attenuated total reflection (ATR) waveguide enabling surface-enhanced infrared absorption (SEIRA) spectroscopic studies for detecting a variety of analytes in aqueous phase with remarkably enhanced IR band intensities. Finally, the proposed ATR-SEIRA strategy enabled quantitatively analyzing adenine in aqueous solution after optimizing the amount of CNDs, the solution pH, and potential CND aggregation.

Surface Enhanced on Infrared Absorption (SEIRAS) and Raman Spectroscopy (SERS) are nondestructive analytic techniques used to detect low concentrations and recognize the fingerprints of molecules. The recognition of the absorption from samples by conventional infrared spectroscopy (IR) via Attenuated Total Reflection (ATR) is difficult for molecules with a low signal strength. However, developed structures with SERS and SEIRAS effect present problems such as high cost, low stability, and low compatibility. Research into new media to obtain greater amplification is largely based on the creation of nanoscale structures with symmetrical arrangements and reproducible distances, resulting in aggregates of nanoparticles that help generate hot spots which are active for amplification. The sol-gel and electrospinning method for the obtention of ceramics provides an alternative means by which to produce said substrates. Fibers of nanometric scale provide an increase of surface area which allows more contact to occur with analytes. Consequently, in this study, a silica-titania-silver nanostructured support that amplifies signal intensity for Raman and infrared spectroscopy was developed. The silica-titania support was developed by sol-gel and electrospinning techniques, and the as spun fibers were treated at 800 °C. Then, the ceramic fibrous membrane was placed on conductive indium tin oxide plastic to be doped with silver using an electroplating technique, varying the silver nitrate concentration (5, 10 and 20 mM), as well as electrodeposition times (1, 2, 5 and 10 min), with a constant voltage (1 V). Twelve different supports were obtained that showed amplification. The enhancement of infrared signals from pyridine and crystal violet molecules adsorbed on silica-titania-silver (SiO2–TiO2–Ag) nanofibers was studied in situ by Attenuated Total Reflection-Fourier Transformed Infrared Spectroscopy (ATR-FTIR). The highest amplification was obtained by the support doped at 10 min in a 10 mM concentration, with an amplification factor of 2.74 in the band localized at 3301 cm−1. In Raman spectroscopy, the highest amplification factor was 27.03, on the support doped for 5 min at a concentration of 5 mM.

Sulfonated Zn phthalocyanine, as a prospective photosensitizer in the photodynamic therapy of tumors, is investigated by means of Raman, infrared, and fluorescence spectroscopies. Conventional and surface-enhanced spectra from this photosensitizer are obtained and compared. Gold nano-islands attached to silica cores (Au-SiO 2 ) are proposed as nanostructures providing plasmonically enhanced signals. Pronounced enhancement of Raman and infrared spectral bands from sulfonated Zn phthalocyanine allows their more convenient assignment with vibrational modes of sulfonated Zn phthalocyanine. In comparison to Raman and IR, the fluorescence is less enhanced by Au-SiO 2 particles.

His-tag technology was applied for biosensing purposes involving multi-redox center proteins (MRPs). An overview is presented on various surfaces ranging from flat to spherical and modified with linker molecules with nitrile-tri-acetic acid (NTA) terminal groups to bind his-tagged proteins in a strict orientation. The bound proteins are submitted to in situ dialysis in the presence of lipid micelles to form a so-called protein-tethered bilayer lipid membrane (ptBLM). MRPs, such as the cytochrome c oxidase (CcO) from R. sphaeroides and P. denitrificans, as well as photosynthetic reactions centers (RCs) from R. sphaeroides, were thus investigated. Electrochemical and surface-sensitive optical techniques, such as surface plasmon resonance, surface plasmon-enhanced fluorescence, surface-enhanced infrared absorption spectroscopy (SEIRAS) and surface-enhanced resonance Raman spectroscopy (SERRS), were employed in the case of the ptBLM structure on flat surfaces. Spherical particles ranging from µm size agarose gel beads to nm size nanoparticles modified in a similar fashion were called proteo-lipobeads (PLBs). The particles were investigated by laser-scanning confocal fluorescence microscopy (LSM) and UV/Vis spectroscopy. Electron and proton transfer through the proteins were demonstrated to take place, which was strongly affected by the membrane potential. MRPs can thus be used for biosensing purposes under quasi-physiological conditions.