Showing papers on "Fourier transform infrared spectroscopy published in 2015"
TL;DR: The work found a new application of the photocatalyst, Ag3PO4/g-C3N4, in simultaneous environmental protection and energy production.
Abstract: This research was designed for the first time to investigate the activities of photocatalytic composite, Ag3PO4/g-C3N4, in converting CO2 to fuels under simulated sunlight irradiation. The composite was synthesized using a simple in situ deposition method and characterized by various techniques including Brunauer–Emmett–Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and an electrochemical method. Thorough investigation indicated that the composite consisted of Ag3PO4, Ag, and g-C3N4. The introduction of Ag3PO4 on g-C3N4 promoted its light absorption performance. However, more significant was the formation of heterojunction structure between Ag3PO4 and g-C3N4, which efficiently promoted the separation of electron–hole pairs by a Z-scheme mechanism and ultimately ...
794 citations
TL;DR: The principles that underlie the determination of protein secondary structure by FTIR spectroscopy are detailed, as well as the basic steps involved in protein sample preparation, instrument operation,FTIR spectra collection and spectra analysis in order to estimate protein secondary-structural components in aqueous solution.
Abstract: Fourier transform IR (FTIR) spectroscopy is a nondestructive technique for structural characterization of proteins and polypeptides. The IR spectral data of polymers are usually interpreted in terms of the vibrations of a structural repeat. The repeat units in proteins give rise to nine characteristic IR absorption bands (amides A, B and I-VII). Amide I bands (1,700-1,600 cm(-1)) are the most prominent and sensitive vibrational bands of the protein backbone, and they relate to protein secondary structural components. In this protocol, we have detailed the principles that underlie the determination of protein secondary structure by FTIR spectroscopy, as well as the basic steps involved in protein sample preparation, instrument operation, FTIR spectra collection and spectra analysis in order to estimate protein secondary-structural components in aqueous (both H2O and deuterium oxide (D2O)) solution using algorithms, such as second-derivative, deconvolution and curve fitting. Small amounts of high-purity (>95%) proteins at high concentrations (>3 mg ml(-1)) are needed in this protocol; typically, the procedure can be completed in 1-2 d.
757 citations
TL;DR: In this article, the phase of the as-synthesized nickel phosphide nanocrystals (NCs) with different phases (Ni12P5, Ni2P and Ni5P4) were synthesized via the thermal decomposition approach using nickel acetylacetonate as the nickel source, trioctylphosphine as the phosphorus source and oleylamine in 1-octadecene as reductant.
Abstract: Monodispersed nickel phosphide nanocrystals (NCs) with different phases (Ni12P5, Ni2P and Ni5P4) were synthesized via the thermal decomposition approach using nickel acetylacetonate as the nickel source, trioctylphosphine as the phosphorus source and oleylamine in 1-octadecene as the reductant. The phases of the as-synthesized nickel phosphide NCs could easily be controlled by changing the P : Ni precursor ratio. The structure and morphology of the as-synthesized nickel phosphide NCs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and N2 adsorption–desorption. A formation mechanism for the as-synthesized nickel phosphide NCs was proposed. We further studied the influence of the phase of the nickel phosphide NCs on the electrocatalytic properties for the hydrogen evolution reaction (HER). All phases showed good catalytic properties, and the Ni5P4 NCs with a solid structure exhibited higher catalytic activity than the Ni12P5 and Ni2P NCs. This superior catalytic activity is attributed to the higher positive charge of Ni and a stronger ensemble effect of P in Ni5P4 NCs. This study demonstrates that the crystalline phase is important for affecting the electrocatalytic properties.
506 citations
TL;DR: In this article, the authors reported low-cost, green synthesis of zinc oxide (ZnO) nanoparticles using 25% (w/v) of Azadirachta indica (Neem) leaf extract.
484 citations
TL;DR: In this paper, the authors used the Hummers method to estimate the oxidation degree of graphene oxide (GO) powders through the relative intensity of the infrared absorption bands related to oxygen containing groups.
463 citations
TL;DR: GO-Ag nanocomposite, as a kind of antibacterial material, had a great promise for application in a wide range of biomedical applications and was demonstrated to have good cytocompatibility and antibacterial properties.
Abstract: In this work, we report a facile and green approach to prepare a uniform silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite (GO-Ag). The nanocomposite was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet–visible (UV–vis) absorption spectra, and X-ray photoelectron spectroscopy (XPS), which demonstrated that AgNPs with a diameter of approximately 22 nm were uniformly and compactly deposited on GO. To investigate the silver ion release behaviors, HEPES buffers with different pH (5.5, 7, and 8.5) were selected and the mechanism of release actions was discussed in detail. The cytotoxicity of GO-Ag nanocomposite was also studied using HEK 293 cells. GO-Ag nanocomposite displayed good cytocompatibility. Furthermore, the antibacterial properties of GO-Ag nanocomposite were studied using Gram-negative E. coli ATCC 25922 and Gram-positive S. aureus ATCC 6538 by both the plate count method and disk diffusion method. The nanoc...
443 citations
TL;DR: In this paper, the Zeolitic imidazolate framework-8 (ZIF-8) nanosorbent was successfully synthesized via a facile method at room temperature.
389 citations
TL;DR: In this paper, the conversion efficiency of CO2 to fuel on a ZnO/g-C3N4 composite photocatalyst under simulated sunlight irradiation was evaluated.
Abstract: The objective of this research was to prepare, characterize and evaluate the conversion efficiency of CO2 to fuel on a ZnO/g-C3N4 composite photocatalyst under simulated sunlight irradiation. The photocatalyst was synthesized by a simple impregnation method and was characterized by various techniques, including Brunauer–Emmett–Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The characterizations indicate that ZnO and g-C3N4 were uniformly combined. The deposition of ZnO on g-C3N4 showed nearly no effect on its light-absorption performance. However, the interactions between the two components promoted the formation of a hetero-junction structure in the composite, inhibited the recombination of electron–hole pairs and, finally, enhanced the photocatalytic performance of ZnO/g-C3N4. The optimal ZnO/g-C3N4 photocatalyst showed a CO2 conversion rate of 45.6 μmol h−1 gcat−1, which was 4.9 and 6.4 times higher than those of g-C3N4 and P25, respectively. This work represents an important step toward artificial photocatalytic CO2 conversion to fuel using cost-efficient materials.
387 citations
TL;DR: In this article, the authors used the Langmuir, Freundlich and Temkin isotherms to describe the behavior of equilibrium adsorption of the studied mercury ions.
Abstract: Nanocomposites of silica incorporated with carbon nanotubes (silica/CNT) and activated carbon (silica/AC) were synthesized and characterized by scanning electron microscopy (SEM), element mapping, energy dispersive X-ray spectroscopy (EDX), thermogravimetric analyzer (TGA) and Fourier transform infrared spectroscopy (FTIR). Silica/CNT and silica/AC were investigated for efficient removal of mercury ions from aqueous solutions. The adsorbents have been analyzed on the basis of adsorption capacity, reusability, and their application in packed columns. The effects of experimental parameters, like pH, contact time and initial concentrations on the adsorption of mercury ions, were optimized. The kinetic data for the adsorption process obeyed a pseudo-second-order kinetic model with R2 of 0.999. Fitting the data to an intraparticle diffusion model indicated that surface adsorption and intraparticle diffusion were concurrently operating. In addition, this study used the Langmuir, Freundlich and Temkin isotherms to describe the behaviour of equilibrium adsorption. The equilibrium adsorption of the studied mercury ions is best fitted using the Freundlich isotherm, with silica/CNT of higher capacity than silica/AC. The silica/CNT showed better performance than silica/AC indicating silica/CNT has better efficiency.
377 citations
TL;DR: In this paper, the authors used simple calcination of g-C 3 N 4 and Sn 6 O 4 (OH) 4 to obtain high photocatalytic performance for rhodamine B degradation under visible light irradiation.
347 citations
TL;DR: Potentiodynamic polarization and electrochemical impedance spectroscopy measurements demonstrated that the superhydrophobic surface greatly improved the corrosion properties of magnesium alloy in 3.5 wt % aqueous solutions of NaCl, Na2SO4, NaClO3, and NaNO3.
Abstract: A simple, one-step method has been developed to construct a superhydrophobic surface by electrodepositing Mg–Mn–Ce magnesium plate in an ethanol solution containing cerium nitrate hexahydrate and myristic acid. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were employed to characterize the surfaces. The shortest electrodeposition time to obtain a superhydrophobic surface was about 1 min, and the as-prepared superhydrophobic surfaces had a maximum contact angle of 159.8° and a sliding angle of less than 2°. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements demonstrated that the superhydrophobic surface greatly improved the corrosion properties of magnesium alloy in 3.5 wt % aqueous solutions of NaCl, Na2SO4, NaClO3, and NaNO3. Besides, the chemical stability and mechanical durability of the as-prepared superhydrophobic surface were also examined. The presented method is rap...
TL;DR: The synthesized C-dots were characterized by atomic force microscope, transmission electron microscopy, fluorescence spectrophotometer, UV-vis absorption spectra as well as Fourier transform infrared spectroscopy and showed various merits including high fluorescent quantum yield, excellent photostability, low toxicity and satisfactory solubility.
Abstract: A simple, economical, and green method for the preparation of water-soluble, high-fluorescent carbon quantum dots (C-dots) has been developed via hydrothermal process using aloe as a carbon source. The synthesized C-dots were characterized by atomic force microscope (AFM), transmission electron microscopy (TEM), fluorescence spectrophotometer, UV–vis absorption spectra as well as Fourier transform infrared spectroscopy (FTIR). The results reveal that the as-prepared C-dots were spherical shape with an average diameter of 5 nm and emit bright yellow photoluminescence (PL) with a quantum yield of approximately 10.37%. The surface of the C-dots was rich in hydroxyl groups and presented various merits including high fluorescent quantum yield, excellent photostability, low toxicity and satisfactory solubility. Additionally, we found that one of the widely used synthetic food colorants, tartrazine, could result in a strong fluorescence quenching of the C-dots through a static quenching process. The decrease of ...
TL;DR: In this article, the aqueous extracts of Musa paradisica (Banana) peels on mild steel corrosion in 1M HCl as well as change in inhibition efficiency with ripening of the peels are investigated by weight loss measurement, electrochemical impedance spectroscopy, Tafel polarization and atomic force microscopy (AFM) techniques.
TL;DR: The CuFe2O4@C3N4 sample exhibited stable performance without obvious loss of catalytic activity after five successive runs, showing a promising application for the photo-oxidative degradation of environmental contaminants.
TL;DR: Investigation of the relationship between Pb(2+) adsorption and physicochemical properties of biochars produced at different pyrolytic temperatures indicated the dominant role of minerals, and results are useful for screening effective biochar as engineered sorbents to remove or immobilize Pb (2+) in polluted water and soil.
TL;DR: These magnetite nanospheres with hollow interiors successfully remediated Cr(6+) and Pb(2+) from water and can be used to isolate and regenerate the used adsorbent.
TL;DR: These nanocomposite hydrogels with unprecedented stretchability, toughness, and self-healing have been developed by in situ polymerization of acrylamide with the presence of exfoliated montmorillonite layers as noncovalent cross-linkers and are demonstrated to fully heal by dry-reswell treatments.
Abstract: Nanocomposite hydrogels with unprecedented stretchability, toughness, and self-healing have been developed by in situ polymerization of acrylamide with the presence of exfoliated montmorillonite (MMT) layers as noncovalent cross-linkers. The exfoliated MMT clay nanoplatelets with high aspect ratios, as confirmed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results, are well dispersed in the polyacrylamide matrix. Strong polymer/MMT interaction was confirmed by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The effective cross-link densities of these hydrogels are estimated in the range of 2.2–5.7 mol m–3. Uniaxial tensile tests showed a very high fracture elongation up to 11 800% and a fracture toughness up to 10.1 MJ m–3. Cyclic loading–unloading tests showed remarkable hysteresis, which indicates energy dissipation upon deformation. Residual strain after cyclic loadings could be recovered under mild conditions, with the recovery exten...
TL;DR: The as-synthesized N-CDs have been successfully applied for cell imaging and detecting Fe(3+) in biosystem and are employed as a highly sensitive and selective probe for Fe( 3+) detection.
TL;DR: In this paper, a simple and scalable in situ light-assisted method was proposed for the preparation of graphitic C3N4/MoS2 photocatalysts, where MoS2 was formed from the reduction of [MoS4]2− by photogenerated electrons, and was then loaded in situ on the electron outlet points of g-C 3N4.
Abstract: MoS2-decorated graphitic C3N4 (g-C3N4/MoS2) photocatalysts were prepared by a simple and scalable in situ light-assisted method. In this process, MoS2 was formed from the reduction of [MoS4]2− by photogenerated electrons, and was then loaded in situ on the electron outlet points of g-C3N4. The g-C3N4/MoS2 composite was well characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and ultraviolet visible diffuse reflection spectroscopy (UV-DRS). The g-C3N4/MoS2 photocatalysts showed good photocatalytic H2 evolution activity. When the loading amount of MoS2 was increased to 2.89 wt% (g-C3N4/MoS2-2.89%), the highest H2 evolution rate (252 μmol g−1 h−1) was obtained. In addition, g-C3N4/MoS2-2.89% presented stable photocatalytic H2 evolution ability (no noticeable degradation of photocatalytic H2 evolution was detected in 18 h) and good natural light driven H2 evolution ability (the H2 evolution rate was 320 μmol g−1 h−1). A possible photocatalytic mechanism of the MoS2 cocatalyst for the improvement of the photocatalytic activity of g-C3N4 is proposed, where MoS2 can efficiently promote the separation of the photogenerated electrons and holes of g-C3N4, consequently enhancing the H2 evolution activity; this mechanism is supported by the photoluminescence spectroscopy and photoelectrochemical analyses.
TL;DR: In this article, BaTiO3 nanowires with high aspect ratio as inorganic filler and PVDF-HFP as polymer matrix were synthesized via one-step hydrothermal method.
Abstract: Polymer based composites with high dielectric constant were successfully fabricated using BaTiO3 nanowires with high aspect ratio as inorganic filler and PVDF-HFP as polymer matrix. PVDF-HFP/BaTiO3 nanoparticles composites were also prepared as a contrast. The BaTiO3 nanowires were synthesized via one-step hydrothermal method. The BaTiO3 nanowires and its two types of composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. For the composites, breakdown strength measurements, tensile tests and broadband dielectric spectroscopy analyses were also carried out. The results show that the two types of fillers are homogeneously dispersed in the matrix. The dielectric constant of composites filled by BaTiO3 nanowires is larger than that filled by BaTiO3 nanoparticles at the same content. Stronger interfacial polarization was found in PVDF-HFP/BaTiO3 nanowire composites. Two theoretical models were employed to predict the dielectric constants of composites, and the experimental data were consistent with the estimated trend. The enhanced dielectric properties of PVDF-HFP/BaTiO3 nanowire composites are attributed to the superior interfacial polarization and high aspect ratio of BaTiO3 nanowires.
TL;DR: In this paper, the metal-organic framework In-benzenedicarboxylate (MIL-68(In)) and its derivative (In-2-NH2-Benzene-dicaroxylate, MIL-68-In)-NH2) were prepared via a simple solvothermal method.
Abstract: Metal–organic framework In-benzenedicarboxylate (MIL-68(In)) and its derivative (In-2-NH2-benzene-dicarboxylate, MIL-68(In)-NH2) were prepared via a simple solvothermal method. Powder X-ray diffraction (XRD) confirmed the isoreticular nature of MIL-68(In) and MIL-68(In)-NH2, while Fourier transformed infrared spectra (FTIR) proved the effective presence of amino group. Moreover, combined with UV–vis diffuse reflectance spectra (DRS) analysis, it was revealed MIL-68(In)-NH2 shown an extra absorption band in the visible light region with the absorption edge extending to around 440 nm. Importantly, MIL-68(In)-NH2 was proved to perform as an efficient visible-light-driven photocatalyst with considerable activity and stability for the reduction of Cr(VI), which could be attributed to its relatively high CB based on the result of Mott–Schottky experiment. Further experimental results revealed that the addition of hole scavenger and pH value of the reaction solution played important roles in the photocatalytic reduction of Cr(VI). Finally, a possible reaction mechanism had also been investigated in detail.
TL;DR: In this article, the authors systematically summarized the structures and properties of PVDF crystals with different polymorphs, discusses the mechanisms of formation and transformation methods, reviews the crystallization and applications of different PVDF polymorphs in membrane separation, and presents the outlook for applications in membrane operations.
TL;DR: In this paper, Salmalia malabarica gum was used as both reducing and capping agent to synthesize stable gold nanoparticles (AuNPs) with a peak at 520-535 nm in the UV-Vis spectrum.
Abstract: Stable gold nanoparticles (AuNPs) were synthesized
using salmalia malabarica gum as both reducing and capping agent. It is a simple and eco-friendly green synthesis. The successful formation of AuNPs was confirmed by UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction and transmission electron microscopy (TEM). The synthesized AuNPs were characterized by a peak at 520–535 nm in the UV–Vis spectrum. The X-ray diffraction studies indicated that the resulting AuNPs were highly crystalline with face-centred cubic geometry. TEM studies showed that the average particle size of the synthesized AuNPs was 12 ± 2 nm. FTIR analysis revealed that –OH groups present in the gum matrix might be responsible for the reduction of Au+3 into AuNPs. The synthesized AuNPs exhibited good catalytic properties in the reduction of methylene blue and Congo red.
TL;DR: The characterization studies showed that Al-O-Si was formed by the substitution of Al(3+) for the hydrogen of surface Si-OH groups, not only resulting in high dispersion of Al 2O3 and Fe2O3 on SBA-15, but also inducing the greatest amount of surface Lewis acid sites.
Abstract: Fe2O3 and/or Al2O3 were supported on mesoporous SBA-15 by wet impregnation and calcinations with AlC(l)3 and FeCl3 as the metal precursor and were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectra (FTIR) of adsorbed pyridine. Fe2O3/Al2O3@SBA-15 was found to be highly effective for the mineralization of ibuprofen aqueous solution with ozone. The characterization studies showed that Al-O-Si was formed by the substitution of Al3+ for the hydrogen of surface Si-OH groups, not only resulting in high dispersion of Al2O3 and Fe2O3 on SBA-15, but also inducing the greatest amount of surface Lewis acid sites. By studies of in situ attenuated total reflection FTIR (ATR-FTIR), in situ Raman, and electron spin resonance (ESR) spectra, the chemisorbed ozone was decomposed into surface atomic oxygen species at the Lewis acid sites of Al3+ while it was converted into surface adsorbed (OHads)-O-center dot and O-2(-) radicals at the Lewis acid sites of Fe3+. The combination of both Lewis acid sites of iron and aluminum onto Fe2O3/Al2O3@SBA-15 enhanced the formation of (OHads)-O-center dot and O-2(-) radicals, leading to highest reactivity. Mechanisms of catalytic ozonation were proposed for the tested catalysts on the basis of all the experimental information.
TL;DR: In this paper, the behavior of amino group-functionalized porous silicon (PS) intended to be used in bio-sensing and/or in medical applications was reported, where Amino-terminated organic layers were deposited onto silicon wafers and PS layers via 3-aminopropyltriethoxysilane (APTES) prepared in freshly hydrolysis solution.
TL;DR: In this paper, the feasibility of generating geopolymers from fly ash using waste glass as an alkaline activator (waterglass family) was explored and the main reaction product in all the systems studied was the alkaline aluminosilicate hydrate gel.
TL;DR: In this article, the additive was obtained through the polymerization of acrylamide monomer in the presence of TiO2 nanoparticles using the solution polymerization method, and the results indicated that the additive contributes to an increase in the viscosity and a decrease in the fluid loss and filter cake thickness.
TL;DR: In this paper, a simple aqueous solution based chemical method for preparation of Cu nanoparticle loaded mesoporous silica SBA-15 (Cu@SBA15) catalysts was reported.
TL;DR: It is observed that the incorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application and the nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field.
TL;DR: In this paper, five different polypyrroles (PPys) with four different oxidants, namely, FeCl3, Fe3·6H2O, Fe2(SO4)3, and Fe2S2O8, were aged for 400 days in ambient air at a temperature of 24°±2°C in a laboratory, where they were not directly exposed to the sun.