Showing papers on "Infrared spectroscopy published in 2018"
TL;DR: A facile method to convert biomolecule-based carbon nanodots (CNDs) into high-surface-area 3D-graphene networks with excellent electrochemical properties and excellent morphological properties is presented.
Abstract: A facile method to convert biomolecule-based carbon nanodots (CNDs) into high-surface-area 3D-graphene networks with excellent electrochemical properties is presented. Initially, CNDs are synthesized by microwave-assisted thermolysis of citric acid and urea according to previously published protocols. Next, the CNDs are annealed up to 400 °C in a tube furnace in an oxygen-free environment. Finally, films of the thermolyzed CNDs are converted into open porous 3D turbostratic graphene (3D-ts-graphene) networks by irradiation with an infrared laser. Based upon characterizations using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy, a feasible reaction mechanism for both the thermolysis of the CNDs and the subsequent laser conversion into 3D-ts-graphene is presented. The 3D-ts-graphene networks show excellent morphological properties, such as a hierarchical porous structure and a high surface area, as well as promising electrochemical properties. For example, nearly ideal capacitive behavior with a volumetric capacitance of 27.5 mF L-1 is achieved at a current density of 560 A L-1 , which corresponds to an energy density of 24.1 mWh L-1 at a power density of 711 W L-1 . Remarkable is the extremely fast charge-discharge cycling rate with a time constant of 3.44 ms.
287 citations
11 Sep 2018
270 citations
TL;DR: The interaction between phonon polaritons and molecular vibrations reaches experimentally the onset of the strong coupling regime, while numerical simulations predict that vibrational strong coupling can be fully achieved and could become a viable platform for sensing, local control of chemical reactivity and infrared cavity optics experiments.
Abstract: Enhanced light-matter interactions are the basis of surface-enhanced infrared absorption (SEIRA) spectroscopy, and conventionally rely on plasmonic materials and their capability to focus light to nanoscale spot sizes. Phonon polariton nanoresonators made of polar crystals could represent an interesting alternative, since they exhibit large quality factors, which go far beyond those of their plasmonic counterparts. The recent emergence of van der Waals crystals enables the fabrication of high-quality nanophotonic resonators based on phonon polaritons, as reported for the prototypical infrared-phononic material hexagonal boron nitride (h-BN). In this work we use, for the first time, phonon-polariton-resonant h-BN ribbons for SEIRA spectroscopy of small amounts of organic molecules in Fourier transform infrared spectroscopy. Strikingly, the interaction between phonon polaritons and molecular vibrations reaches experimentally the onset of the strong coupling regime, while numerical simulations predict that vibrational strong coupling can be fully achieved. Phonon polariton nanoresonators thus could become a viable platform for sensing, local control of chemical reactivity and infrared quantum cavity optics experiments. Infrared spectroscopy is a powerful tool for characterizing materials based on their specific vibrational fingerprints. However, its ability to characterize small amounts or thin layers of molecules is limited by their extremely small infrared absorption cross-sections. This limitation can be overcome by surface-enhanced infrared absorption spectroscopy (SEIRA), which exploits the field enhancement provided by plasmon polaritons on thin metal films or resonant metallic nanostructures. Now, Rainer Hillenbrand from CIC nanoGUNE in San Sebastian (Spain) and co-workers have developed highly sensitive phonon-polariton resonators for SEIRA detection, based on hexagonal boron nitride ribbons, which exhibit quality factors much higher than their plasmonic counterparts. They demonstrated phonon-enhanced molecular vibrational spectroscopy with sensitivity down to femtomolar levels, approaching the strong coupling limit.
252 citations
TL;DR: In this article, the authors demonstrate a mid-infrared dual-comb spectrometer covering 2.6 to 5.2 µm with comb-tooth resolution, sub-MHz frequency precision and accuracy, and a spectral signal-to-noise ratio as high as 6,500.
Abstract: Mid-infrared dual-comb spectroscopy has the potential to supplant conventional Fourier-transform spectroscopy in applications requiring high resolution, accuracy, signal-to-noise ratio and speed. Until now, mid-infrared dual-comb spectroscopy has been limited to narrow optical bandwidths or low signal-to-noise ratios. Using digital signal processing and broadband frequency conversion in waveguides, we demonstrate a mid-infrared dual-comb spectrometer covering 2.6 to 5.2 µm with comb-tooth resolution, sub-MHz frequency precision and accuracy, and a spectral signal-to-noise ratio as high as 6,500. As a demonstration, we measure the highly structured, broadband cross-section of propane from 2,840 to 3,040 cm−1, the complex phase/amplitude spectra of carbonyl sulfide from 2,000 to 2,100 cm−1, and of a methane, acetylene and ethane mixture from 2,860 to 3,400 cm−1. The combination of broad bandwidth, comb-mode resolution and high brightness will enable accurate mid-infrared spectroscopy in precision laboratory experiments and non-laboratory applications including open-path atmospheric gas sensing, process monitoring and combustion. By employing difference-frequency generation, a mid-infrared dual-comb spectrometer covering the 2.6 to 5.2 µm range is demonstrated with comb-tooth resolution, sub-MHz frequency precision and accuracy, and a spectral signal-to-noise ratio as high as 6,500.
242 citations
TL;DR: In this paper, solar light responsive Bi3+ and Fe2+ doped ZnO were synthesized and used for photocatalytic degradation of norfloxacin (NOR), an emerging water pollutant.
193 citations
TL;DR: The antibacterial activity exhibited by the actinomycetes mediated biosynthesized CuO NPs suggests that it can combat both human as well as fish bacterial pathogens.
Abstract: The aim of the present study was actinomycetes mediated biosynthesis of copper oxide nanoparticles (CuO NPs) and evaluation of its antibacterial activity against selected human and fish pathogens. The biosynthesized CuO NPs were characterized by UV–Visible (UV-Vis) spectroscopy. The presence of capping agents over the metal nanoparticles was confirmed by Fourier-Transform Infrared Spectroscopy (FT-IR). The crystalline nature of the CuO NPs was illustrated by X- Ray diffractometer (XRD). The average size of the biosynthesized CuO NPs from XRD and Transmission Electron Microscopy (TEM) was 61.7 nm. The XRD and Energy Dispersive X-Ray spectroscopy (EDX) suggests the purity of the biosynthesized CuO NPs. The morphology and size was viewed under Scanning Electron Microscopy (SEM). The Dynamic Light Scattering (DLS) results provided the zeta potential of − 31.1 mV which further confirmed the stability of the CuO NPs. The biosynthesized CuO NPs showed higher antibacterial activity (zone of inhibition) against various human and fish bacterial pathogens (Staphylococcus aureus, Bacillus cereus, Proteus mirabilis, Edwardsiella tarda, Aeromonas caviae, Aeromonas hydrophila and Vibrio anguillarum). The antibacterial activity of CuO NPs was significantly higher than the activity exhibited by cell free supernatant of actinomycetes. Among the pathogens tested B. cereus was more susceptible (25.3 mm) to biosynthesized CuO NPs. The antibacterial activity exhibited by the actinomycetes mediated biosynthesized CuO NPs suggests that it can combat both human as well as fish bacterial pathogens. To the best of our knowledge, this is the first report on actinomycetes mediated biosynthesis of CuO NPs.
175 citations
TL;DR: In this article, the phonon polaritons and molecular vibrations reached experimentally the onset of the strong coupling regime, while numerical simulations predict that vibrational strong coupling can be fully achieved.
Abstract: Enhanced light-matter interactions are the basis of surface enhanced infrared absorption (SEIRA) spectroscopy, and conventionally rely on plasmonic materials and their capability to focus light to nanoscale spot sizes. Phonon polariton nanoresonators made of polar crystals could represent an interesting alternative, since they exhibit large quality factors, which go far beyond those of their plasmonic counterparts. The recent emergence of van der Waals crystals enables the fabrication of high-quality nanophotonic resonators based on phonon polaritons, as reported for the prototypical infrared-phononic material hexagonal boron nitride (h-BN). In this work we use, for the first time, phonon-polariton-resonant h-BN ribbons for SEIRA spectroscopy of small amounts of organic molecules in Fourier transform infrared spectroscopy. Strikingly, the interaction between phonon polaritons and molecular vibrations reaches experimentally the onset of the strong coupling regime, while numerical simulations predict that vibrational strong coupling can be fully achieved. Phonon polariton nanoresonators thus could become a viable platform for sensing, local control of chemical reactivity and infrared quantum cavity optics experiments.
162 citations
TL;DR: In this paper, the authors used the stretching frequencies and adsorption energies of CO bound to Pt as a fingerprint of the specific structure of the stable Ptiso species and compared the properties of single-atom Pt catalysts and sub-nanometer Ptmetal and Ptox clusters.
160 citations
TL;DR: ZnO-SnO2 (ZS) nanocomposites with different compositions were prepared using a simple coprecipitation method with zinc chloride, stannic chloride pentahydrate, and ammonium hydroxide as raw materials as discussed by the authors.
158 citations
TL;DR: In this article, a noncentrosymmetric double borate Rb3EuB6O12 was designed and synthesized by the solid state reaction method, and its crystallographic parameters were obtained by Rietveld analysis.
144 citations
TL;DR: Experimental 2D infrared spectra of coherent light–matter excitations––molecular vibrational polaritons are reported and a quantum-mechanical model is developed which incorporates both nuclear and electrical anharmonicities and provides the basis for interpreting this class of 2D IR spectra.
Abstract: We report experimental 2D infrared (2D IR) spectra of coherent light–matter excitations––molecular vibrational polaritons. The application of advanced 2D IR spectroscopy to vibrational polaritons challenges and advances our understanding in both fields. First, the 2D IR spectra of polaritons differ drastically from free uncoupled excitations and a new interpretation is needed. Second, 2D IR uniquely resolves excitation of hybrid light–matter polaritons and unexpected dark states in a state-selective manner, revealing otherwise hidden interactions between them. Moreover, 2D IR signals highlight the impact of molecular anharmonicities which are applicable to virtually all molecular systems. A quantum-mechanical model is developed which incorporates both nuclear and electrical anharmonicities and provides the basis for interpreting this class of 2D IR spectra. This work lays the foundation for investigating phenomena of nonlinear photonics and chemistry of molecular vibrational polaritons which cannot be probed with traditional linear spectroscopy.
TL;DR: In this article, eugenol and ginger essential oils were incorporated in different film formulations to produce active films that might be used as food packaging, and optical, microstructural, mechanical, and barrier properties were characterized.
Abstract: Eugenol and ginger essential oils were incorporated in different film formulations to produce active films that might be used as food packaging. Optical, microstructural, mechanical, and barrier properties were characterized, as well as their antioxidant activity. Fourier transformed infrared spectroscopy analysis confirmed the presence of new bands with addition of eugenol or ginger essential oils, and scanning electron microscopy and atomic force microscopy analyses showed an increases in roughness values (p
TL;DR: In this article, the authors investigated the reactivities and coverages of atop-and bridge-bound CO on a polycrystalline Cu electrode in contact with alkaline electrolytes and showed that a fraction of atopbound CO converts to bridge-bonded CO when the total CO coverage drops below the saturation coverage.
Abstract: Surface-adsorbed CO is generally considered a reactive on-pathway intermediate in the aqueous electrochemical reduction of CO2 on Cu electrodes. Though CO can bind to a variety of adsorption sites (e.g., atop or bridge), spectroscopic studies of the Cu/electrolyte contact have mostly been concerned with atop-bound CO. Using surface-selective infrared (IR) spectroscopy, we have investigated the reactivities and coverages of atop- and bridge-bound CO on a polycrystalline Cu electrode in contact with alkaline electrolytes. We show here that (1) a fraction of atop-bound CO converts to bridge-bonded CO when the total CO coverage drops below the saturation coverage and (2) unlike atop-bound CO, bridge-bonded CO is an unreactive species that is not reduced at a potential of −1.75 V vs SHE. Our results suggest that bridge-bonded CO is not an on-pathway intermediate in CO reduction. Using density functional theory (DFT) calculations, we further reveal that the activation barrier for the hydrogenation of bridge-bon...
TL;DR: A single shot is sufficient to extract spectral and kinetic characteristics of several intermediates in the bacteriorhodopsin photocycle and paves the way for the noninvasive analysis of enzymatic conversions with high time resolution, broad spectral coverage, and minimal sample consumption.
Abstract: The kinetic analysis of irreversible protein reactions requires an analytical technique that provides access to time-dependent infrared spectra in a single shot. Here, we present a spectrometer based on dual-frequency-comb spectroscopy using mid-infrared frequency combs generated by quantum cascade lasers. Attenuation of the intensity of the combs by molecular vibrational resonances results in absorption spectra covering 55 cm-1 in the fingerprint region. The setup has a native resolution of 0.3 cm-1, noise levels in the μOD range, and achieves sub-microsecond time resolution. We demonstrate the simultaneous recording of both spectra and transients of the photoactivated proton pump bacteriorhodopsin. More importantly, a single shot, i.e., a single visible light excitation, is sufficient to extract spectral and kinetic characteristics of several intermediates in the bacteriorhodopsin photocycle. This development paves the way for the noninvasive analysis of enzymatic conversions with high time resolution, broad spectral coverage, and minimal sample consumption.
TL;DR: In this paper, the authors demonstrate a spectroscopic method for the in situ determination of the surface pH using the CO2 reduction reaction as a model system, which is employed to monitor the ratio of vibrational bands of carbonate and bicarbonate as a function of electrode potential.
Abstract: Localized concentration gradients within the electrochemical double layer during various electrochemical processes can have wide-ranging impacts; however, experimental investigation to quantitatively correlate the rate of surface-mediated electrochemical reaction with the interfacial species concentrations has historically been lacking. In this work, we demonstrate a spectroscopic method for the in situ determination of the surface pH using the CO2 reduction reaction as a model system. Attenuated total reflectance surface-enhanced infrared absorption spectroscopy is employed to monitor the ratio of vibrational bands of carbonate and bicarbonate as a function of electrode potential. Integrated areas of vibrational bands are then compared with those obtained from calibration spectra collected in electrolytes with known pH values to determine near-electrode proton concentrations. Experimentally determined interfacial proton concentrations are then related to the resultant concentration overpotentials to exam...
TL;DR: In this paper, a new magnetic interphase palladium catalyst has been synthesized on chitosan-biguanidine coated-magnetic Fe3O4 nanoparticles, which demonstrated high catalytic activity as a recyclable nanocatalyst toward Suzuki-Miyaura crosscoupling reactions, at room temperature.
TL;DR: It is found that both the precursor and certain core materials have an influence on the coating composition, while other parameters, such as the precursor concentration, aerosol residence time and temperature, influence the morphology, but hardly the chemical composition.
Abstract: Nanoparticles are coated in-flight with a plasma-enhanced chemical vapor deposition (PECVD) process at ambient or elevated temperatures (up to 300 °C). Two silicon precursors, tetraethyl orthosilicate (TEOS) and hexamethyldisiloxane (HMDSO), are used to produce inorganic silica or silica-organic shells on Pt, Au and TiO₂ particles. The morphology of the coated particles is examined with transmission electron microscopy (TEM) and the chemical composition is studied with Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). It is found that both the precursor and certain core materials have an influence on the coating composition, while other parameters, such as the precursor concentration, aerosol residence time and temperature, influence the morphology, but hardly the chemical composition. The coated particles are used to demonstrate simple applications, such as the modification of the surface wettability of powders and the improvement or hampering of the photocatalytic activity of titania particles.
TL;DR: A series of metal hexacyanoferrates, with a general formula of K x M y [Fe(CN) 6 ] z · q H 2 O, with x, y, z and q representing stoichiometric numbers and M = Fe (1), Co (2), Ni (3 ), and Cu (4), were prepared by a simple co-precipitation reaction as discussed by the authors.
TL;DR: Data indicate that the phototoxic response may result from the release of both CO and the rhenium-containing photoproduct, as well as the production of 1O2.
Abstract: Fifteen water-soluble rhenium compounds of the general formula [Re(CO)3(NN)(PR3)]+, where NN is a diimine ligand and PR3 is 1,3,5-triaza-7-phosphaadamantane (PTA), tris(hydroxymethyl)phosphine (THP), or 1,4-diacetyl-1,3,7-triaza-5-phosphabicylco[3.3.1]nonane (DAPTA), were synthesized and characterized by multinuclear NMR spectroscopy, IR spectroscopy, and X-ray crystallography. The complexes bearing the THP and DAPTA ligands exhibit triplet-based luminescence in air-equilibrated aqueous solutions with quantum yields ranging from 3.4 to 11.5%. Furthermore, the THP and DAPTA complexes undergo photosubstitution of a CO ligand upon irradiation with 365 nm light with quantum yields ranging from 1.1 to 5.5% and sensitize the formation of 1O2 with quantum yields as high as 70%. In contrast, all of the complexes bearing the PTA ligand are nonemissive and do not undergo photosubstitution upon irradiation with 365 nm light. These compounds were evaluated as photoactivated anticancer agents in human cervical (HeLa),...
TL;DR: The results revealed that, the in-growth of Cu-BTC resulted in production of biocidal synthetic fabrics without any ecotoxic effects at the as-used Cu- BTC content.
TL;DR: In this article, Fourier transform infrared spectroscopy (FTIR) has been used extensively for chemical characterization of mineralized tissues in the past few decades, and it is an ideal technique to analyze...
Abstract: Fourier transform infrared spectroscopy (FTIR) has been used extensively for chemical characterization of mineralized tissues in the past few decades. FTIR is an ideal technique to analyze ...
TL;DR: The ZnWO4 nanocrystals obtained at 160 °C exhibited excellent photodegradation of Rhodamine under ultraviolet light irradiation, which was found to be related to the surface energy and the types of clusters formed on the surface of the catalyst.
Abstract: The present joint experimental and theoretical work provides in-depth understanding on the morphology and structural, electronic, and optical properties of ZnWO4 nanocrystals. Monoclinic ZnWO4 nanocrystals were prepared at three different temperatures (140, 150, and 160 °C) by a microwave hydrothermal method. Then, the samples were investigated by X-ray diffraction with Rietveld refinement analysis, field-emission scanning electron microscopy, transmission electronic microscopy, micro-Raman and Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence measurements. First-principles theoretical calculations within the framework of density functional theory were employed to provide information at the atomic level. The band structure diagram, density of states, Raman and infrared spectra were calculated to understand the effect of structural order-disorder on the properties of ZnWO4. The effects of the synthesis temperature on the above properties were rationalized. The band structure revealed direct allowed transitions between the VB and CB and the experimental results in the ultraviolet-visible region were consistent with the theoretical results. Moreover, the surface calculations allowed the association of the surface energy stabilization with the temperature used in the synthesis of the ZnWO4 nanocrystals. The photoluminescence properties of the ZnWO4 nanocrystals prepared at 140, 150, and 160 °C were attributed to oxygen vacancies in the [WO6] and [ZnO6] clusters, causing a red shift of the spectra. The ZnWO4 nanocrystals obtained at 160 °C exhibited excellent photodegradation of Rhodamine under ultraviolet light irradiation, which was found to be related to the surface energy and the types of clusters formed on the surface of the catalyst.
TL;DR: Time-resolved kinetics lead us to conclude that CT excited states relax to a ground-state intermediate with a time constant of ~3 µs, followed by a structural relaxation to the original CN-Cz2:PO-T2T configuration within ~14 ²s.
Abstract: The lack of structural information impeded the access of efficient luminescence for the exciplex type thermally activated delayed fluorescence (TADF). We report here the pump-probe Step-Scan Fourier transform infrared spectra of exciplex composed of a carbazole-based electron donor (CN-Cz2) and 1,3,5-triazine-based electron acceptor (PO-T2T) codeposited as the solid film that gives intermolecular charge transfer (CT), TADF, and record-high exciplex type cyan organic light emitting diodes (external quantum efficiency: 16%). The transient infrared spectral assignment to the CT state is unambiguous due to its distinction from the local excited state of either the donor or the acceptor chromophore. Importantly, a broad absorption band centered at ~2060 cm−1 was observed and assigned to a polaron-pair absorption. Time-resolved kinetics lead us to conclude that CT excited states relax to a ground-state intermediate with a time constant of ~3 µs, followed by a structural relaxation to the original CN-Cz2:PO-T2T configuration within ~14 µs. The development of exciplex-type hosts for thermally activated delayed fluorescence organic light-emitting diodes is hindered by a lack of structural information for these donor:acceptor blends. Here, the authors report the pump-probe Step-Scan Fourier transform IR spectra for a D:A exciplex host.
TL;DR: In this paper, the effects of amine-modified graphene oxide on dispersion and micro-hardness of epoxy based nanocomposites are reported, where the modified Hummers method was used followed by hexamethylenediamine functionalization.
TL;DR: This work presents optical conductivity-based mid-infrared (mid-IR) biosensors that allow for sensitive and quantitative measurements of low-molecular-weight analytes as well as the enhancement of spectral fingerprints and demonstrates enhanced fingerprinting of minute quantities of glucose and polymer molecules.
Abstract: Optical devices are highly attractive for biosensing as they can not only enable quantitative measurements of analytes but also provide information on molecular structures. Unfortunately, typical refractive index-based optical sensors do not have sufficient sensitivity to probe the binding of low-molecular-weight analytes. Non-optical devices such as field-effect transistors can be more sensitive but do not offer some of the significant features of optical devices, particularly molecular fingerprinting. We present optical conductivity-based mid-infrared (mid-IR) biosensors that allow for sensitive and quantitative measurements of low-molecular-weight analytes as well as the enhancement of spectral fingerprints. The sensors employ a hybrid metasurface consisting of monolayer graphene and metallic nano-antennas and combine individual advantages of plasmonic, electronic and spectroscopic approaches. First, the hybrid metasurface sensors can optically detect target molecule-induced carrier doping to graphene, allowing highly sensitive detection of low-molecular-weight analytes despite their small sizes. Second, the resonance shifts caused by changes in graphene optical conductivity is a well-defined function of graphene carrier density, thereby allowing for quantification of the binding of molecules. Third, the sensor performance is highly stable and consistent thanks to its insensitivity to graphene carrier mobility degradation. Finally, the sensors can also act as substrates for surface-enhanced infrared spectroscopy. We demonstrated the measurement of monolayers of sub-nanometer-sized molecules or particles and affinity binding-based quantitative detection of glucose down to 200 pM (36 pg/mL). We also demonstrated enhanced fingerprinting of minute quantities of glucose and polymer molecules.
TL;DR: In this article, the photocatalytic activity of as-prepared photocatalyst was tested for the reduction of CO2 under UV light in a continuous flow gas-phase photoreactor.
Abstract: Pt/TiO2 and Pt/TiO2-COK-12 photocatalysts have been prepared by a deposition-precipitation method and characterized by means of X-ray diffraction (XRD), N2 adsorption isotherms, transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The photocatalytic activity of as-prepared photocatalyst was tested for the photocatalytic reduction of CO2 under UV light in a continuous flow gas-phase photoreactor. CH4 and CO were detected as major carbon products for all photocatalysts, with minor amounts of CH3OH. Carbon monoxide is the main product obtained over TiO2 regardless of the presence of COK-12 as a mesoporous support, whereas Pt leads to CO2 reduction towards CH4 formation, with a selectivity that reaches ca. 100% with optimum loading. Supporting the Pt/TiO2 catalysts on COK-12 preserves the selectivity of the reaction towards CH4 and further improves the overall activity of the Pt/TiO2 materials. After-reaction attenuated total reflection infrared spectroscopy (ATR-IR) and in-situ near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) have been employed to identify reaction intermediates and used to explain the observed selectivity trends.
TL;DR: Using ultrafast broadband two-dimensional infrared spectroscopy, it is shown that the vibrational spectrum of the aqueous proton is fully consistent with a protonated water complex broadly defined as a Zundel-like H5O2+ motif.
Abstract: Given the critical role of the aqueous excess proton in redox chemistry, determining its structure and the mechanism of its transport in water are intense areas of experimental and theoretical research The ultrafast dynamics of the proton’s hydration structure has made it extremely challenging to study experimentally Using ultrafast broadband two-dimensional infrared spectroscopy, we show that the vibrational spectrum of the aqueous proton is fully consistent with a protonated water complex broadly defined as a Zundel-like H5O2+ motif Analysis of the inhomogeneously broadened proton stretch two-dimensional lineshape indicates an intrinsically asymmetric, low-barrier O–H+–O potential that exhibits surprisingly persistent distributions in both its asymmetry and O–O distance This structural characterization has direct implications for the extent of delocalization exhibited by a proton’s excess charge and for the possible mechanisms of proton transport in water Although ubiquitous throughout chemistry and biology, the structure and transport mechanism of the aqueous proton in solution remain elusive Through advances in ultrafast broadband 2D IR spectroscopy, the structure of the aqueous proton is revealed to have a charge-delocalized H5O2+ Zundel-like core arrangement with surprisingly persistent structural heterogeneity
TL;DR: A straightforward in operando attenuated total reflectance infrared spectroscopy method is developed that allows visualization of changes of all infrared active bands that occur as a consequence of reduction/oxidation processes within several battery systems.
Abstract: Organic materials are receiving an increasing amount of attention as electrode materials for future post lithium-ion batteries due to their versatility and sustainability. However, their electrochemical reaction mechanism has seldom been investigated. This is a direct consequence of a lack of straightforward and broadly available analytical techniques. Herein, a straightforward in operando attenuated total reflectance infrared spectroscopy method is developed that allows visualization of changes of all infrared active bands that occur as a consequence of reduction/oxidation processes. In operando infrared spectroscopy is applied to the analysis of three different organic polymer materials in lithium batteries. Moreover, this in operando method is further extended to investigation of redox reaction mechanism of poly(anthraquinonyl sulfide) in a magnesium battery, where a reduction of carbonyl bond is demonstrated as a mechanism of electrochemical activity. Conclusions done by the in operando results are complemented by synthesis of model compound and density functional theory calculation of infrared spectra.
TL;DR: In this paper, the polymethyldopa (PMDP)-coated Fe3O4@PMDPs were successfully deposited using PMDP as a core-shell magnetic coordinator and stabilizer agent, and the structure, morphology and physicochemical properties of the synthesized nanoparticles were characterized by different analytical techniques such as energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscope (FESEM), Fourier transform infrared spectrograph (FT-IR), high resolution transmission electron microscopy (HR-TEM), induct