Showing papers on "Infrared spectroscopy published in 2016"
TL;DR: It is demonstrated that FTIR is a tool that can quantitatively probe short range interactions in starch structure, however, the assumptions of linear relationships between starch ordered structure and peak ratios are overly simplistic.
455 citations
TL;DR: The results of photocatalytic reactions, emission decay measurements, and time-resolved infrared spectroscopy indicated that Ag nanoparticles on C3N4 collected electrons having lifetimes of several milliseconds from the conduction band of C2N4, which were transferred to the excited state of RuRu', thereby promoting photocatalyst CO2 reduction driven by two-step photoexcitation of C3n4 and RuRu'.
Abstract: A metal-free organic semiconductor of mesoporous graphitic carbon nitride (C3N4) coupled with a Ru(II) binuclear complex (RuRu′) containing photosensitizer and catalytic units selectively reduced CO2 into HCOOH under visible light (λ > 400 nm) in the presence of a suitable electron donor with high durability, even in aqueous solution. Modification of C3N4 with Ag nanoparticles resulted in a RuRu′/Ag/C3N4 photocatalyst that exhibited a very high turnover number (>33000 with respect to the amount of RuRu′), while maintaining high selectivity for HCOOH production (87–99%). This turnover number was 30 times greater than that reported previously using C3N4 modified with a mononuclear Ru(II) complex, and by far the highest among the metal-complex/semiconductor hybrid systems reported to date. The results of photocatalytic reactions, emission decay measurements, and time-resolved infrared spectroscopy indicated that Ag nanoparticles on C3N4 collected electrons having lifetimes of several milliseconds from the co...
365 citations
TL;DR: An overview of recent static and time-resolved vibrational spectroscopic studies of liquid water from ambient conditions to the supercooled state, as well as of crystalline and amorphous ice forms, reveals a coherent picture of water dynamics and energetics.
Abstract: We present an overview of recent static and time-resolved vibrational spectroscopic studies of liquid water from ambient conditions to the supercooled state, as well as of crystalline and amorphous ice forms. The structure and dynamics of the complex hydrogen-bond network formed by water molecules in the bulk and interphases are discussed, as well as the dissipation mechanism of vibrational energy throughout this network. A broad range of water investigations are addressed, from conventional infrared and Raman spectroscopy to femtosecond pump–probe, photon-echo, optical Kerr effect, sum-frequency generation, and two-dimensional infrared spectroscopic studies. Additionally, we discuss novel approaches, such as two-dimensional sum-frequency generation, three-dimensional infrared, and two-dimensional Raman terahertz spectroscopy. By comparison of the complementary aspects probed by various linear and nonlinear spectroscopic techniques, a coherent picture of water dynamics and energetics emerges. Furthermore,...
270 citations
TL;DR: In this article, the authors developed a technique that allows spectral measurements in the infrared range using visible-spectral-range components, based on nonlinear interference of infrared and visible photons, produced via spontaneous parametric down conversion.
Abstract: The refractive index and absorption coefficient of a medium in the infrared range are measured using visible spectral range components. The technique relies on nonlinear interference of infrared and visible photons, produced by down-conversion. Spectral measurements in the infrared optical range provide unique fingerprints of materials, which are useful for material analysis, environmental sensing and health diagnostics1. Current infrared spectroscopy techniques require the use of optical equipment suited for operation in the infrared range, components of which face challenges of inferior performance and high cost. Here, we develop a technique that allows spectral measurements in the infrared range using visible-spectral-range components. The technique is based on nonlinear interference of infrared and visible photons, produced via spontaneous parametric down conversion2,3. The intensity interference pattern for a visible photon depends on the phase of an infrared photon travelling through a medium. This allows the absorption coefficient and refractive index of the medium in the infrared range to be determined from the measurements of visible photons. The technique can substitute and/or complement conventional infrared spectroscopy and refractometry techniques, as it uses well-developed components for the visible range.
236 citations
TL;DR: In this article, a comprehensive optical characterization of Co3O4 and CoO with Raman scattering and Fourier transform infrared spectroscopy (FTIR) is presented, where two transverse optical (TO) phonons and their corresponding longitudinal optical phonons of CoO4 above 500 cm-1 are observed in both transmission and diffuse reflectance with LO/TO intensity ratios depending on particle size and the incident angle of FTIR beam.
Abstract: Although Raman spectral fingerprints of Co3O4 have been well established, the infrared spectrum of Co3O4 is less understood due to its dependence on sample morphologies and experimental configurations. The same is true for both Raman and infrared spectra of CoO. In this study, we present a comprehensive optical characterization of Co3O4 and CoO with Raman scattering and Fourier transform infrared spectroscopy (FTIR). Two of the transverse optical (TO) phonons and their corresponding longitudinal optical (LO) phonons of Co3O4 above 500 cm–1 are observed in both transmission and diffuse reflectance with LO/TO intensity ratios depending on particle size and the incident angle of FTIR beam. CoO is featured by a broad infrared band around 510 cm–1. In contrast to many previous reports, no Raman-active phonon line is observed, which is in agreement with the selection rule for rock-salt CoO. Nevertheless, CoO can still be characterized by Raman scattering from magnetic excitations in its antiferromagnetic phase ...
201 citations
TL;DR: Potassium 4,5-bis(dinitromethyl)furoxanate was synthesized readily from cyanoacetic acid and its positive oxygen balance, high density, and superior detonation performance make it a competitive replacement as a green primary explosive.
Abstract: Potassium 4,5-bis(dinitromethyl)furoxanate was synthesized readily from cyanoacetic acid. It was characterized by IR spectroscopy, elemental analysis, NMR spectroscopy, and differential scanning calorimetry (DSC), and the structure was confirmed by X-ray single-crystal diffraction. Its positive oxygen balance, high density (2.130 g cm−3), sensitivity (IS=2 J, FS=5 N), and calculated heat of formation (−421.0 kJ mol−1), combined with its calculated superior detonation performance (D=7759.0 m s−1, P=27.3 GPa), make it a competitive replacement as a green primary explosive.
192 citations
TL;DR: In this article, a new angle on the Hummers method was described, and the chemical and structural evolutions during step II oxidation was demonstrated for the first time using various techniques including atomic force microscopy (AFM), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible light (UV-vis) spectroscopic, Fourier transform infrared spectroscope (FT-IR), 13C nuclear magnetic resonance (NMR), and zeta-potentiometry.
Abstract: Hummers method has been used for 50 years to prepare graphene oxide (GO) by oxidizing graphite using Mn2O7. In this work, a new angle on Hummers method is described. The oxidation procedure before the addition of water, which has been respected as the main oxidation step of Hummers method, is named step I oxidation, and the widely ignored further oxidation step after the addition of water is named step II oxidation. The chemical and structural evolutions during step II oxidation was demonstrated for the first time using various techniques including atomic force microscopy (AFM), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible light (UV–vis) spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), 13C nuclear magnetic resonance (NMR), and zeta-potentiometry. Step II oxidation influences the size of GO, defects within the layers, and functional groups on the surface, which affect the thermal stability of GO and the properties of resultant thermally reduced G...
188 citations
TL;DR: In this paper, Raman and infrared spectra of hybrid organic-inorganic MAPbX3 perovskites (MA = CH3NH3, X = Cl, Br, I) and their mixed-halide derivatives were recorded at three laser wavelengths (514, 785, and 1064 nm) under on- and off-resonance conditions, as well as at room temperature and 100 K.
Abstract: This study reports Raman and infrared spectra of hybrid organic–inorganic MAPbX3 perovskites (MA = CH3NH3, X = Cl, Br, I) and their mixed-halide derivatives. Raman spectra were recorded at three laser wavelengths (514, 785, and 1064 nm) under on- and off-resonance conditions, as well as at room temperature and 100 K. The use of different excitation wavelengths allowed the unambiguous acquisition of “true” Raman spectra from the perovskites, without degradation or photoinduced structural changes. Low-frequency PbX vibrational modes were thoroughly identified by comparison of Raman and far-IR results. Red Raman frequency shifts for almost all MA vibrations from 200 to 3200 cm–1, and particularly intense for the torsional mode, were observed toward heavy halide derivatives, indicative of strengthening the interaction between halides and the organic cation inside the inorganic cage. Different MA–X bonding schemes are evidenced by torsional mode pairs emerging in the orthorhombic phase. MAPbBr3 was further cha...
184 citations
TL;DR: In this article, the potential of exploding wire technique (EWT) to synthesize the copper nanoparticles using the copper metal in a plate and wire geometry was explored, which revealed existence of additional minority CuO phase, not determined earlier through XRD and TEM analysis.
164 citations
TL;DR: 2D IR spectra of a semisynthetic KcsA channel with site-specific heavy isotope labels in the selectivity filter provide an instantaneous snapshot of the multi-ion configurations and structural distributions that occur spontaneously in the filter.
Abstract: Potassium channels are responsible for the selective permeation of K+ ions across cell membranes. K+ ions permeate in single file through the selectivity filter, a narrow pore lined by backbone carbonyls that compose four K+ binding sites. Here, we report on the two-dimensional infrared (2D IR) spectra of a semisynthetic KcsA channel with site-specific heavy (13C18O) isotope labels in the selectivity filter. The ultrafast time resolution of 2D IR spectroscopy provides an instantaneous snapshot of the multi-ion configurations and structural distributions that occur spontaneously in the filter. Two elongated features are resolved, revealing the statistical weighting of two structural conformations. The spectra are reproduced by molecular dynamics simulations of structures with water separating two K+ ions in the binding sites, ruling out configurations with ions occupying adjacent sites.
TL;DR: The highest activity is achieved by combination of a number of factors: (i) specific surface area, (ii) adsorption edge energy, (iii) crystallite size, and (iv) efficient separation of the charge carriers, where the efficient separation is the most decisive parameter.
Abstract: TiO2/g-C3N4 photocatalysts with the ratio of TiO2 to g-C3N4 ranging from 0.3/1 to 2/1 were prepared by simple mechanical mixing of pure g-C3N4 and commercial TiO2 Evonik P25. All the nanocomposites were characterized by X-ray powder diffraction, UV–vis diffuse reflectance spectroscopy, photoluminescence, X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, transmission electron microscopy, photoelectrochemical measurements, and nitrogen physisorption. The prepared mixtures along with pure TiO2 and g-C3N4 were tested for the photocatalytic reduction of carbon dioxide and photocatalytic decomposition of nitrous oxide. The pure g-C3N4 exhibited the lowest photocatalytic activity in both cases, pointing to a very high recombination rate of charge carriers. On the other hand, the most active photocatalyst toward all the products was (0.3/1)TiO2/g-C3N4. The highest activity is achieved by combination of a number of factors: (i) specific surface area, (ii) adsorption edge energy, (iii) cr...
TL;DR: A 3D fluorescent amide-functionalized Cd(II)-based metal-organic framework (MOF) with molecular formula [Cd5Cl6(L)(HL)2]·7H2O (1) was synthesized under solvothermal conditions using CdCl2·H2
Abstract: A new 3D fluorescent amide-functionalized Cd(II)-based metal–organic framework (MOF) with molecular formula [Cd5Cl6(L)(HL)2]·7H2O (1) was synthesized under solvothermal conditions using CdCl2·H2O and 4-(1H-tetrazol-5-yl)-N-[4-(1H-tetrazol-5-yl)phenyl]benzamide (H2L) in DMF/methanol in the presence of conc. HCl. Single-crystal X-diffraction analysis reveals that the 3D framework structure of 1 is constructed from octahedrally coordinated Cd2+ ions interconncted by chloride anions and ditopic tetrazolate-based ligand molecules. The phase-purity of the compound was confirmed by X-ray powder diffraction (XRPD) analysis, infrared spectroscopy, and elemental analysis. Thermogravimetric analysis suggests that 1 is thermally stable up to 300 °C. Steady-state fluorescence titration experiments reveal that activated 1′ can selectively detect 2,4,6-trinitrophenol (TNP) in the presence of other competing nitroaromatic compounds with a detection limit of 42.84 ppb. Recyclability experiments reveal that 1′ retains its ...
TL;DR: In this article, the interactions between a Cu-based metal-organic framework (MOF), Cu-BTC, and an ionic liquid (IL), 1-ethyl-3methylimidazolium ethyl sulfate, were studied by employing density functional theory (DFT) calculations and vibrational spectroscopy.
Abstract: The interactions between a Cu-based metal–organic framework (MOF), Cu-BTC, and an ionic liquid (IL), 1-ethyl-3-methylimidazolium ethyl sulfate, were studied by employing density functional theory (DFT) calculations and vibrational spectroscopy. The Fourier transform infrared (FTIR) and Raman spectra show that the confinement of the IL in the MOF has significant impact on the structure of the MOF as well as on the IL. Raman spectra and DFT calculations reveal a perturbation of the symmetry of the MOF structure due to the interaction of the IL anion with the Cu ions. FTIR and Raman spectra show that the molecular interactions in turn influence the structure of the ion pair. Inside the MOF, two different types of structure of IL ion pairs are formed. One ion-pair structure exhibits enhanced interionic interactions by strengthening the hydrogen bonding between cation and anion, whereas the other structure corresponds to weaker interactions between the IL cation and anion. Moreover, it is shown that the IL imi...
TL;DR: Graphene-manganese ferrite (rG-MnFe2O4) was developed to degrade NH3 as mentioned in this paper, which showed a degradation of 92.0% was achieved through visible light irradiation of 50.0mg L−1 NH3-N solution at pH 10.5 in the presence of 1.0mmol/L H2O2 for 10h.
TL;DR: A new metal-organic framework, Fe-BTTri, is found to be highly selective in the adsorption of CO over a variety of other gas molecules, making it extremely effective, for example, in the removal of trace CO from mixtures with H2, N2, and CH4.
Abstract: A new metal–organic framework, Fe-BTTri (Fe3[(Fe4Cl)3(BTTri)8]2·18CH3OH, H3BTTri =1,3,5-tris(1H-1,2,3-triazol-5-yl)benzene)), is found to be highly selective in the adsorption of CO over a variety of other gas molecules, making it extremely effective, for example, in the removal of trace CO from mixtures with H2, N2, and CH4. This framework not only displays significant CO adsorption capacity at very low pressures (1.45 mmol/g at just 100 μbar), but, importantly, also exhibits readily reversible CO binding. Fe-BTTri utilizes a unique spin state change mechanism to bind CO in which the coordinatively unsaturated, high-spin FeII centers of the framework convert to octahedral, low-spin FeII centers upon CO coordination. Desorption of CO converts the FeII sites back to a high-spin ground state, enabling the facile regeneration and recyclability of the material. This spin state change is supported by characterization via infrared spectroscopy, single crystal X-ray analysis, Mossbauer spectroscopy, and magnetic...
TL;DR: In this paper, the effect of alkali activation process conditions on the IR spectra, on which amount and types of zeolites in the resultant geopolymers influence significantly, was investigated.
TL;DR: In this article, the reversible charging of a Co-1,4-benzenedicarboxylate MOF (Co-BDC) prepared via an one-pot solvothermal method was studied for use as the anode in a Li-ion cell.
TL;DR: In this paper, anatase TiO2 nanoparticles with both exposed (101) and (001) facets synchronously incorporated with g-C3N4 and graphene, were successfully prepared via a simple one-step solvothermal route.
TL;DR: The first infrared study of water uptake at controlled vapor pressure in single walled carbon nanotubes with diameters ranging from 0.7 to 2.1 nm is reported, revealing a predominant contribution of loose H bonds even for fully hydrated states, irrespective of the nanotube size.
Abstract: A groundbreaking discovery in nanofluidics was the observation of the tremendously enhanced water permeability of carbon nanotubes, those iconic objects of nanosciences. The origin of this phenomenon is still a subject of controversy. One of the proposed explanations involves dramatic modifications of the H-bond network of nanoconfined water with respect to that of bulk water. Infrared spectroscopy is an ideal technique to follow modifications of this network through the inter- and intramolecular bonds of water molecules. Here we report the first infrared study of water uptake at controlled vapor pressure in single walled carbon nanotubes with diameters ranging from 0.7 to 2.1 nm. It reveals a predominant contribution of loose H bonds even for fully hydrated states, irrespective of the nanotube size. Our results show that, while the dominating loosely bond signature is attributed to a one-dimensional chain structure for small diameter nanotubes, this feature also results from a water layer with “free” OH ...
TL;DR: The value of the CE-DFCS approach is established for studying much larger and more complex molecules than have been probed so far, enabling complex molecules and their kinetics to be studied with orders-of-magnitude improvements in efficiency, spectral resolution and specificity.
Abstract: For more than half a century, high-resolution infrared spectroscopy has played a crucial role in probing molecular structure and dynamics. Such studies have so far been largely restricted to relatively small and simple systems, because at room temperature even molecules of modest size already occupy many millions of rotational/vibrational states, yielding highly congested spectra that are difficult to assign. Targeting more complex molecules requires methods that can record broadband infrared spectra (that is, spanning multiple vibrational bands) with both high resolution and high sensitivity. However, infrared spectroscopic techniques have hitherto been limited either by narrow bandwidth and long acquisition time, or by low sensitivity and resolution. Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) combines the inherent broad bandwidth and high resolution of an optical frequency comb with the high detection sensitivity provided by a high-finesse enhancement cavity, but it still suffers from spectral congestion. Here we show that this problem can be overcome by using buffer gas cooling to produce continuous, cold samples of molecules that are then subjected to CE-DFCS. This integration allows us to acquire a rotationally resolved direct absorption spectrum in the C-H stretching region of nitromethane, a model system that challenges our understanding of large-amplitude vibrational motion. We have also used this technique on several large organic molecules that are of fundamental spectroscopic and astrochemical relevance, including naphthalene, adamantane and hexamethylenetetramine. These findings establish the value of our approach for studying much larger and more complex molecules than have been probed so far, enabling complex molecules and their kinetics to be studied with orders-of-magnitude improvements in efficiency, spectral resolution and specificity.
TL;DR: A family of titanium-oxo clusters possessing the {Ti18O27} core in which the 18 Ti(IV)-ions are uniquely connected with μ-oxO ligands into a triple-decked pentagonal prism was obtained, providing new titanium oxide candidates for surface modifications and homogeneous photocatalysis.
Abstract: By using solubility control to crystallize the prenucleation clusters of hydrosol, a family of titanium-oxo clusters possessing the {Ti18O27} core in which the 18 Ti(IV)-ions are uniquely connected with μ-oxo ligands into a triple-decked pentagonal prism was obtained. The cluster cores are wrapped by external sulfate and aqua ligands, showing good solubilities and stabilities in a variety of solvents including acetonitrile and water and allowing their solution chemistry being studied by means of electrospray ionization mass spectroscopy, 17O NMR, and vibrational spectroscopy. Furthermore, this study provides new titanium oxide candidates for surface modifications and homogeneous photocatalysis.
TL;DR: The stability of ethylidyne is deduced on the basis of the spectroscopic observations of CO, which stems from the dissociation of CO2 into CO + O in the reverse water-gas shift mechanism and a reactive species that undergoes direct conversion in the Sabatier methanation process.
Abstract: The interaction of CO, CO2, CO + H2, CO2 + H2, and CO + CO2 + H2 with the nickel (110) single crystal termination has been investigated at 10–1 mbar in situ as a function of the surface temperature in the 300–525 K range by means of infrared-visible sum frequency generation (IR–vis SFG) vibrational spectroscopy and by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS). Several stable surface species have been observed and identified. Besides atomic carbon and precursors for graphenic C phases, five nonequivalent CO species have been distinguished, evidencing the role of coadsorption effects with H and C atoms, of H-induced activation of CO, and of surface reconstruction. At low temperature, carbonate species produced by the interaction of CO2 with atomic oxygen, which stems from the dissociation of CO2 into CO + O, are found on the surface. A metastable activated CO2– species is also detected, being at the same time a precursor state toward dissociation into CO and O in the reverse water–gas...
TL;DR: In this paper, the role of the catalysts in the different parts of the reaction mechanism was investigated by in-situ methods in the photocatalytic transformation of the methane-carbon dioxide system.
Abstract: The photocatalytic transformation of the methane-carbon dioxide system was investigated by in-situ methods in the present study. Titanate nanotube (TNT) supported gold and rhodium catalysts were used in the catalytic tests. Our main goal was the analysis of the role of the catalysts in the different parts of the reaction mechanism. The catalysts were characterized by X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) and diffuse reflectance UV–vis spectroscopy (DR-UV–vis). Photocatalytic tests were performed in a continuous flow quartz reactor equipped with mass spectrometer detector and mercury-arc UV source. Diffuse reflectance infrared spectroscopy (DRIFTS) was used to analyze the surface of the catalyst during photoreaction. Post-catalytic tests were also carried out on the catalysts including XPS, temperature programmed reduction (TPR) and Raman spectroscopy methods in order to follow the changes of the materials. Titanate nanotube can stabilize even the smallest, molecular-like Au clusters which showed the highest activity in the reactions. Approximately 3% methane conversion was reached in the best cases while the carbon dioxide conversion was not traceable. It was revealed that water has a very important role in the oxidation reaction. The main discovered reaction routes are methane dehydrogenation and oxidation, the methyl coupling and the forming of structured carbon deposits on the catalyst surface. The source of the surplus CO can be mostly the reduction of carbon dioxide. During the reduction process photoelectrons and hydrogen ions brings about the CO2 reduction via CO2 − radical anion.
TL;DR: In this paper, the authors examined the feasibility of aluminum antennas for SEIRA, by designing and fabricating asymmetric aluminum cross antennas with nanometer-scale gaps, which enable the simultaneous detection of multiple infrared vibrational resonances over a broad region of the mid-infrared spectrum.
Abstract: While there has been a tremendous increase of recent interest in noble metal-based antennas as substrates for surface-enhanced infrared absorption spectroscopy, more abundant and manufacturable metals may offer similar or additional opportunities for this mid-infrared sensing modality. Here we examine the feasibility of aluminum antennas for SEIRA, by designing and fabricating asymmetric aluminum cross antennas with nanometer-scale gaps. The asymmetric cross design enables the simultaneous detection of multiple infrared vibrational resonances over a broad region of the mid-infrared spectrum. The presence of the Al2O3 amorphous surface oxide layer not only passivates the metal antenna structures but also enables a very straightforward covalent binding chemistry for analyte molecules to the antenna through multiple approaches, in this case by the use of carboxylic acid functional groups. The aluminum–oxygen stretching mode of the oxide can be used as a self-calibration standard to quantify the number of ana...
TL;DR: Infrared spectroscopy and powder neutron diffraction experiments were used to confirm this mechanism of selective O2 binding, and gas adsorption measurements also reveal excellent O2 /N2 selectivity with substantial O2 reversibility at room temperature.
Abstract: A chromium(II)-based metal-organic framework Cr3 [(Cr4 Cl)3 (BTT)8 ]2 (Cr-BTT; BTT(3-) =1,3,5-benzenetristetrazolate), featuring coordinatively unsaturated, redox-active Cr(2+) cation sites, was synthesized and investigated for potential applications in H2 storage and O2 production. Low-pressure H2 adsorption and neutron powder diffraction experiments reveal moderately strong Cr-H2 interactions, in line with results from previously reported M-BTT frameworks. Notably, gas adsorption measurements also reveal excellent O2 /N2 selectivity with substantial O2 reversibility at room temperature, based on selective electron transfer to form Cr(III) superoxide moieties. Infrared spectroscopy and powder neutron diffraction experiments were used to confirm this mechanism of selective O2 binding.
TL;DR: The potential and challenges of mid-infrared spectroscopy for protein analysis are discussed as are the potential and limitations of different IR spectroscopic techniques enabling protein analysis.
Abstract: Mid-infrared (MIR) spectroscopy investigates the interaction of MIR photons with both organic and inorganic molecules via the excitation of vibrational and rotational modes, providing inherent molecular selectivity. In general, infrared (IR) spectroscopy is particularly sensitive to protein structure and structural changes via vibrational resonances originating from the polypeptide backbone or side chains; hence information on the secondary structure of proteins can be obtained in a label-free fashion. In this review, the challenges for IR spectroscopy for protein analysis are discussed as are the potential and limitations of different IR spectroscopic techniques enabling protein analysis. In particular, the amide I spectral range has been widely used to study protein secondary structure, conformational changes, protein aggregation, protein adsorption, and the formation of amyloid fibrils. In addition to representative examples of the potential of IR spectroscopy in various fields related to protein analysis, the potential of protein analysis taking advantage of miniaturized MIR systems, including waveguide-enhanced MIR sensors, is detailed.
TL;DR: In this article, the effect of different solvents and polymeric surfactants such as carboxymethyl cellulose, polyethylene glycol, and polyvinyl alcohol on the morphology, particle size, and crystal structure of the final product was investigated.
Abstract: Zinc tungstate nanoparticles have been successfully synthesized by a precipitation method in the presence of different polymeric surfactants. This study aimed to investigate the effect of different solvents and polymeric surfactants such as carboxymethyl cellulose, polyethylene glycol, and polyvinyl alcohol on the morphology, particle size, and crystal structure of the final product. The as-synthesized products were characterized by powder x-ray diffraction analysis, scanning electron microscopy, ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, and energy-dispersive x-ray spectroscopy techniques. Furthermore, the hysteresis loop of the zinc tungstate nanoparticles at room temperature revealed paramagnetic behavior. Photocatalysis results revealed that maximum methyl orange decolorization of 85% was achieved with ZnWO4 nanoparticles in 240 min under visible-light irradiation. The saturation magnetization, remanent magnetization, and coercivity of the ZnWO4 nanoparticles were 0.003 emu/g, 0.0005 emu/g, and 110 Oe, respectively.
TL;DR: The novel, thermally stable explosive 5,5'-bis(2,4,6-trinitro-phenyl)-2,2'-bi(1,3,4-oxadiazole) (TKX-55) is reported and shows outstanding properties (detonation velocity, detonation pressure, sensitivity toward mechanical stimuli, and temperature of decomposition).
Abstract: The novel, thermally stable explosive 5,5'-bis(2,4,6-trinitro-phenyl)-2,2'-bi(1,3,4-oxadiazole) (TKX-55) is reported. This compound can be prepared by means of a facile synthetic procedure and shows outstanding properties (detonation velocity, detonation pressure, sensitivity toward mechanical stimuli, and temperature of decomposition). TKX-55 was isolated and characterized by means of mass spectrometry, multinuclear (1 H, 13 C) NMR spectroscopy, and vibrational spectroscopy (IR and Raman). The structure in the crystalline state was determined by low-temperature single-crystal X-ray diffraction. From the calculated standard molar enthalpy of formation (CBS-4M) and the densities, the Chapman-Jouguet detonation properties were predicted by using the EXPLO5 V6.01 thermochemical computer code. The sensitivity of TKX-55 towards impact, friction, and electrostatic discharge was determined. The shock reactivity (explosiveness) of TKX-55 was measured by applying the small-scale shock reactivity test.
TL;DR: In this article, the authors developed a novel approach to obtain CQDs/g-C3N4 nanocomposite with effective interfacial contact by incorporating negatively charged carbon quantum dots (CQDs) and tailor-made proton-functionalized graphitic carbon nitride (GNT) via the electrostatic self-assembly strategy.