Fourier transform infrared-temperature programmed

Fourier Transform Infrared-Temperature Programmed Desorption... 

Zhang, W.Z., Burckle, E.C., and Smimiotis, P.G. (1999) Charaderization of the acidity of ultrastable Y, morden-ite, and ZSM-12 via NH3-stepwise temperature programmed desorption and Fourier transform infrared spectroscopy. Micropor. Mesopor. 

Three series of LaCoi. CuxOs, LaMni.xCuxOs, LaFei x(Cu, Pd)x03 perovskites prepared by reactive grinding were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed desorption (TPD) of O2, NO + O2, and CsHg in the absence or presence of H2O, Fourier transform infrared (FTIR) spectroscopy as well as activity evaluations without or with 10% steam in the feed. This research was carried out with the objective to investigate the water vapor effect on the catalytic behavior of the tested perovskites. An attempt to propose a steam deactivation mechanism and to correlate the water resistance of perovskites with their properties has also been done. 

Koehler, B.G., Middlebrook, AM., and Tolbert, M.A. (1992) Characterisation of model polar stratospheric cloud forts using Fourier transform infrared spectroscopy and temperature programmed desorption, J. Geophys. Res. 97,8065-8074. 

The experiments were performed in two different ultra high vacuum (UHV) chambers using two different Pt(lll) single crystals. The X-ray photoelectron spectra were obtained in a chamber with a base pressure of lxlO" Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped with low energy electron diffraction (LEED), an X-ray photoelectron spectrometer (XPS), a quadrupole mass spectrometer (QMS) for temperature programmed desorption (TPD), and a Fourier transform infrared spectrometer (FTIR) for reflection absorption infrared spectroscopy (RAIRS). All RAIRS and TPD experiments were performed in a second chamber with a base pressure of 2 X 10 ° Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped for LEED, Auger electron spectroscopy (AES) and TPD experiments with a QMS. The chamber is coupled to a commercial FTIR spectrometer, a Bruker IFS 66v/S. To achieve maximum sensitivity, an... 

Kaul et at (58) also used the elementary steps of Eq. (19) to model their results for CO oxidation over Pt/Si02, for which they used the experimental techniques of transient Fourier-transform infrared (FTIR), temperature-programmed reaction, and concentration-programmed reaction (59). They later applied the same methods to the CO oxidation over Rh/Si02. In the numerical calculations many parameters were taken from surface science results, and the agreement between experiment and simulation is good 60) when spatial nonuniformities are not present. 

Instruments IR-85 Fourier Transform infrared spectrometer, through an IBM GC-IR interface. The interface consisted of a gold-coated Pyrex light-pipe with potassium bromide windows. A scan rate of 6 scans/sec and a spectral resolution of 8 cm- - were used for data acquisition. Samples were introduced into the system via splitless injections. A fused silica capillary column, 30 m x 0.32 mm i d DB-WAX (dj 1.0 pm), was employed with the outlet end connected directly to the GC-IR light-pipe entrance. Helium was used as the carrier gas at an average linear velocity of 41.4 cm/sec (35°C). No make-up gas was employed in the system. The column temperature was programmed from 35°C to 180°C at 2°C/min. The GC-IR light-pipe assembly was maintained at 170°C. 

There are several experimental techniques available to study the chemical properties of clusters on surfaces and when used in combination, a detailed picture can be obtained. A classical approach is the use of temperature programmed desorption (TPD) and temperature programmed reaction (TPR) spectroscopy [39, 239,240] in combination with temperature-dependent and eventually time-dependent Fourier transformed infrared spectroscopy (FTIR) [39,192,241-244]. This combination allows for obtaining information on estimates of binding energies of reactant molecules (TPD), for characterizing... 

The mechanistic details for the combustion of CO on supported gold clusters are discussed next. Small gold clusters, Au (n < 20) were deposited after size-selection from the gas phase onto defect-poor and defect-rich MgO(lOO) films. As described in Sect. 1.5.1, defect-rich films are characterized by a given density ( 5% ML) of extended defects and point defects (F centers), whereas for defect-poor films the density of F-centers is negligible. The CO-oxidation was studied by combined temperature programmed reaction (TPR) and Fourier transform infrared spectroscopy and the obtained results were compared to extensive ab initio calculations [209,368,369]. 

The following techniques for the characterization of supported vanadia catalysts and vanadia will briefly reviewed temperature programmed reduction (TPR) [26, 30], oxidation (TPO) [30] and desorption (TPD) [33, 36, 41, 44] laser Raman spectroscopy (LSR) [5, 25, 35, 36, 39, 44] Fourier-transform infrared spectroscopy... 

Characterization of the catalysts was made using high-resolution transmission electron microscopy (TEM) (Hitachi H-9000), X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and Fourier transform-infrared spectroscopy (FT-IR). 

A Cu0/Ti02 catalysts was characterized by NH3 temperature programmed desorption (TPD) and Fourier transform infrared (FT-IR) spectroscopy and tested for NH3 oxidation. TPD measurements showed two forms of adsorbed NH3, one of which could be removed by treatment with water vapour. FT-IR spectra showed NH3 coordinated to Lewis acid sites, which gave rise, after treatment at 150°C, to adsorbed hydrazine and nitrxyl species. In NH3 oxidation tests conversions up to 90% were observed. N2 was the main product, N2O and NO being formed to lower extents. The addition of water vapour in the feed influenced the product distribution. A reaction mechanism was proposed, involving adsorbed hydrazine, nitroxyl and amido species as intermediates for N2, N2O and NO production, respectively. 

All activity measurements were conducted in an in-situ infrared reactor cell placed in the sample compartment of a DIGILAB 15C Fourier Transform Infrared (FTIR) Spectrometer. The reactor, described in detail elsewhere [11], consisted of two aluminum flanges with CaF2 IR transparent windows, a gas inlet and outlet, and two foil fast response thermocouples which were placed in direct contat with the catalyst. The reactor temperature was maintained constant by external heaters controlled by a temperature programmed controller. A Teflon coated recycle pump permitted to maintain near isothermal conditions and improve the mixing in the reactor. The reactor and associated lines were tested for activity at the highest temperature used, and it was found to have negligible activity. 

The adsorption of furan, 2,5-dihydrofuran and tetrahydrofuran on sodium-ion exchanged faujasites with different Si/Al ratios was studied by combining temperature-programmed desorption (TPD), inelastic neutron scattering (INS), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), quantum mechanical computations and Monte-Carlo simulations. 

The spent catalysts were characterized by chemical analysis (carbon content), temperature programmed oxidation coupled to a mass spectrometer (TPO/MS) and thermal analysis (DTA and TG). The samples were also submitted to extraction of soluble coke in a soxhiet apparatus with n-hexane and dichloromethane for 24h, after being treated with fluoridric acid (40%) at room temperature (2h), followed by reflux with hydrocloric acid (36%) for 2h. The extracts were analyzed by gas-chromatography-mass spectrometry (GC/MS), Fourier transformer infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV) and X ray diffraction. The insoluble fraction was analyzed by X ray diffraction and FTIR. 

The acidity of sites in the walls for surfactant templated aluminosilicates, or silicates doped with other transition metals prepared via surfactant templating can be characterised using a range of techniques including temperature-programmed desorption (TPD) of ammonia, ° solid-state NMR with probe molecules such as trimethylphosphine which bind to acid sites or Fourier transform infrared and diffuse reflectance UV-Vis with ammonia or CO probes.These techniques show that... 

Freriks, I. L. C., van Wechem, H. M. H., Stuiver, J. C. M., Bouwman, R. (1981). Potassium-catalysed gasification of carbon with steam a temperature-programmed desorption and fourier transform infrared study. Fuel, 60, 463—470. 

Fourier Transformation Infrared (FT-IR) spectra were recorded using a Peridn-Elmer RX-1 spectrometer with KBr pellet from 4,000 to 400 cm . The H NMR and NMR speetra were acquired at 300 MHz on a Bruker-300 spectrometer with 1% tetra-methylsilane (TMS) as an internal standard. The DSC analysis was carried out with a Qj series TA instruments differential scanning calorimeter using 5-7 mg of the sample crimped in alumininm pans at a heating rate of 10°C/min and nnder nitrogen atmosphere with a flow rate of 40 ml/mia The MW reactions were carried out in a Milestone Ine., laboratory MW system with a frequency of 2,450 MHz and controllable power system (max 1,000 W). A 50 ml (diameter 5 cm) Teflon reaction vessel was used. The temperature and time of the reaction were controlled by pre-programmed Easywave software system. 

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