Topic
Fourier transform infrared spectroscopy
About: Fourier transform infrared spectroscopy is a research topic. Over the lifetime, 48250 publications have been published within this topic receiving 1134369 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this article, a highly oxidized graphite oxide was synthesized from natural graphite powder by oxidation with KMnO4 in concentrated H2SO4 followed by hydrolysis, washing and centrifugation.
585 citations
••
579 citations
••
TL;DR: In this paper, the reduction of CeO2 by hydrogen has been studied from 300-1200 K by several complementary techniques: temperature-programmed reduction (TPR), magnetic susceptibility measurements, Fourier transform infrared (FTIR), UV-VIS diffuse reflectance and X-ray photoelectron (XP) spectroscopy.
Abstract: The reduction of CeO2 by hydrogen has been studied from 300–1200 K by several complementary techniques: temperature-programmed reduction (TPR) and magnetic susceptibility measurements, Fourier-transform infrared (FTIR), UV–VIS diffuse reflectance and X-ray photoelectron (XP) spectroscopy. Two CeO2 samples were used with B.E.T. surface areas of 115 and 5 m2 g–1, respectively. The concentration of Ce3+ was determined in situ by measuring the magnetic susceptibility and the CeIII photoemission line. The reduction began at 473 K, irrespective of the initial surface area of the ceria. In the case of the low-surface-area sample, an intermediate reduction step was observed between 573 and 623 K, corresponding to the reduction of the surface. This intermediate step was less easily observed in the case of the high-surface-area ceria. In both cases, the reduction led to a stabilised state with the formal composition CeO1.83. Temperatures higher than 923 K were required to reduce the ceria further. The surface CeIII content determined by XPS was close to that determined by magnetic susceptibility measurements. The intensity of the 17 000 cm–1 band in the UV–VIS reflectance spectrum also varied with the degree of reduction. Finally, the evolution of the surface species observed by IR spectroscopy was in good agreement with the results from the other techniques. The IR results indicated large changes in the concentration and nature of both the hydroxyl and the polydentate carbonate species during the reduction process. The adsorption of oxygen on samples previously reduced to the composition CeO1.83 led to almost complete reoxidation at room temperature. The state of the initial B.E.T. surface did not influence the oxidation process. A slight excess adsorption of oxygen was evident on the surface. This was thermodesorbed at 380 K under vacuum.
577 citations
••
TL;DR: In this article, lead adsorption on chitosan/PVA beads was found to be strongly pH-dependent and displayed a maximum uptake capacity at pH around 4 and a minimum at pH about 6.4.
Abstract: Removal of lead from aqueous solution with chitosan/PVA (poly(vinyl alcohol)) hydrogel beads was studied in batch adsorption experiments at various solution pH values (2−7.6). Lead adsorption on chitosan/PVA beads was found to be strongly pH-dependent and displayed a maximum uptake capacity at pH around 4 and a minimum at pH about 6.4. ζ-Potential study indicated that chitosan/PVA beads possessed positive ζ-potentials at pH 6.3. Hence, adsorption occurred even though the interaction between lead and chitosan/PVA beads was electrostatically repulsive at pH < 6.3. Complexation, ion exchange, and electrostatic interaction are all believed to play a role in lead adsorption on chitosan/PVA beads, but the relative importance of each of these mechanisms varies with solution pH values. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy spectra suggested that lead adsorption was mainly through interactions with the N atoms in chitosan in the pH rang...
576 citations
••
TL;DR: In this article, a two-step pyrolysis of melamine (C3H6N6) at 800°C for 2 h under vacuum conditions is described.
Abstract: Graphitic carbon nitride (g-C3N4) has been synthesized via a two-step pyrolysis of melamine (C3H6N6) at 800°C for 2 h under vacuum conditions. X-ray diffraction (XRD) patterns strongly indicate that the synthesized sample is g-C3N4. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) morphologies indicate that the product is mainly composed of graphitic carbon nitride. The stoichiometric ratio of C:N is determined to be 0.72 by elemental analysis (EA). Chemical bonding of the sample has been investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Electron energy loss spectroscopy (EELS) verifies the bonding state between carbon and nitrogen atoms. Optical properties of the g-C3N4 were investigated by PL (photoluminescence) measurements and UV–Vis (ultraviolet–visible) absorption spectra. We suppose its luminescent properties may have potential application as component of optical nanoscale devices. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were also performed.
568 citations