Reduction temperature-programed

Temperature Programmed Reduction. Temperature-programmed reduction (TPR), one of the indirect analysis methods, yielded data that suggested that Sn was not reduced to zero-valent state (10,16). Burch (15) has reviewed early work on the characterization of this type of catalyst. Lieske and Volter (21) reported, based on the results obtained from TPR studies, that a minor part of the tin is reduced to the metal, and this Sn(O) combined with Pt to form "alloy clusters" but the major portion of the tin is reduced to only the... 

The actual activation process is the result of all the factors mentioned above and, consequently, relatively complicated. A short article [121] and another one cited above [81], however, suggest that the fundamental approach presented above is very useful in understanding the overall phenomenon and controlling the activation process. Because of this complexity, no single method can provide all the information necessary for optimizing activation by reduction. Temperature programmed reduction used in previous examples and... 

Figure 1.13 shows a diagram of a xsorb automated system used to conduct chemisorption measurements, volumetric analysis, temperature programmed reduction, temperature programmed oxidation, etc. 

Temperature-Programmed Reduction for Solid Materials Characterization, Alan Jones and Brian McNichol... 

In general, the use of temperature programming to achieve only a reduction in batch time is not always practical. Besides being difficult, if not impossible, to cany out on a large scale, it can seriouly affect the quality of the polylmer produced. For example, wide ranges in polymerzation temperature lead to broad molecular weight distributions (MWD) which may be undesirable. 

Catalysts were characterized using SEM (Hitachi S-4800, operated at 15 keV for secondary electron imaging and energy dispersive spectroscopy (EDS)), XRD (Bruker D4 Endeavor with Cu K radiation operated at 40 kV and 40 mA), TEM (Tecnai S-20, operated at 200 keV) and temperature-programmed reduction (TPR). Table 1 lists BET surface area for the selected catalysts. 

Temperature-programmed reduction TPR was used to determine the reduction behaviors of the catalyst samples. It was carried out using 50 mg of a sample and a temperature ramp from 35 to 800°C at 5°C/min. The carrier gas was 5% H2 in Ar. A cold trap was placed before the detector to remove water produced during the reaction. 

A. Jones and B.D. McNicol (eds.), Temperature Programmed Reduction for Solid Materials and Characterization, New York M. Dekker, 1986... 

Fig. 2. Temperature-programmed reduction profiles for Ni2P/Si02, Ni2P/Al20j, and Ni2P /C-AI2O3.

In this work, the catalytic reforming of CH4 by CO2 over Ni based catalysts was investigated to develop a high performance anode catalyst for application in an internal reforming SOFC system. The prepared catalysts were characterized by N2 physisorption, X-ray diffraction (XRD) and temperature programmed reduction (TPR). 

Physical properties of the prepared catalysts were measured by an adsorption analyzer [Quantachrome Co., Autosorb-lC]. The structure of prepared catalysts were investigated by XRD [Simmazdu Co., XRD-6000] with a Cu-Ka radiation source (X = 1.54056 A), voltage of 40.0 kV, ciurent of 30.0 mA and scan speed of 5.0 deg/min. Also, temperature-programmed reduction (TPR) profiles of the samples were investigated by a sorption analyzer [Micromeritics Co., Autochem II] and obtained by heating the samples from room temperature to 1100°C at a rate of lOTl/min in a 5 % H2/Ar gas flow (50 ml/min). 

Figure 4.20. Experimental set-ups for temperature programmed reduction, oxidation and desorption. Upper left The reactor is inside the oven, the temperature of which can be increased linearly with time. Gas consumption by the catalyst is monitored by the change in thermal conductivity of the gas mixture it is essential to remove traces of water, etc. because these would affect the thermal conductivity measurement. Lower-left ...

Temperature-programmed reaction methods form a class of techniques in which a chemical reaction is monitored while the temperature increases linearly in time. Several forms are in use temperature-programmed reduction, oxidation and sulfidation. 

Catalytic Reduction of SO3 Stored in SOx Transfer Catalysts -A Temperature-Programmed Reaction Study... 

In the absence of palladium, the Zr02 support (after treatment under H2 at 773 K in order to remove possible impurities) does not absorb O2 or H2 during successive temperature-programmed oxidations and reductions until 773 K. Moreover, with the Pd/Al203 solid the O2 or H2 consumption never exceed the amounts corresponding to Pd. 

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