Temperature programmed surface reaction TPSR

The chemical reactions occurring on the surface of solid in the process of heating, such as decomposition reaction, reactions between surface and absorbed species and between absorbed species (for example, dehydrogenation, hydrogenolysis, aromati-zation etc), are the research objects of TPSR. The nature of the active site and the mechanism of surface reaction can be revealed. 

TPSR method can be used to study the kinetics and mechanism of surface reaction. The reactants pre-adsorption on the surface takes place reaction during heating process, and the location and the peak shape of the TPSR peak (Tr) can be determined by the kinetic parameters. Reaction on the surface is much more complex than the desorption process. TPSR kinetic equation can be obtained as 

Changing Tr can obtain the different values. Plotting (2 Ig Tr - Ig / ) vs. 1 /%, the activation energy r and the frequency factor kor can be obtained from the slope and intercept of straight line. 

When TPSR was used to study the mechanism of dehydrogenation reaction of n-hexane on Pt/Al203 catalyst, the results showed that the reaction for n-hexane dehydrogenation cyclizating formation benzene may have different courses. 

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The second part of this work will be dedicated to the start of the game what are the pieces motions How can the adsorbed molecules react on the surface and among all the playground, where does the real action take place This is the so-called in situ approach for which techniques such as temperature-programmed surface reaction (TPSR) or transient analysis by pulse injection have been developed. 

Abstract A three-function catalyst model for hydrocarbon SCR of NOx is described, based on experimental evidence for each function, during temperature-programmed surface reactions (TPSR). 

The thermal stability of NOx adsorbed species and their reactivity in the presence of gaseous reductant molecules was addressed by thermal decomposition in He (TPD) or by heating in flowing H2/He mixtures [temperature-programmed surface reaction (TPSR)], respectively. In these cases, after NOx adsorption and He purge at the adsorption temperature (300 100oC), the samples were cooled to RT under flowing He. Then the samples were heated at 15°C/min up to 500-600°C in He (TPD) or in He + H2 (2000 ppm) (H2-TPSR). 

In this work, an attempt is made to show the role of the different metal species present in Co and Co/Pd based FER zeolites, using UV-Vis and H2-TPR experiments, coupled with Temperature Programmed Surface Reaction (TPSR) tests. 

Catalytic runs were carried out in a U-type quartz reactor, under Temperature Programmed Surface Reaction (TPSR) conditions (GHSV= 45000 h"1). The sample was pre-treated in flowing argon from room temperature (RT) to 500 °C, using a heating rate of 5 °C min"1, and kept at 500 °C for lh. Further details are also given elsewhere [19]. 

Using a temperature-programmed surface reaction (TPSR) technique, Li et al. (154) showed that this complete oxidation of methane took place on the NiO catalyst during the CHfOi reaction. Weng et al. (145) used in situ microprobe Raman and in situ time-resolved IR spectroscopies to obtain a relationship between the state of the catalyst and the reaction mechanism. These authors showed that RuC>2 in the Ru/SiC>2 catalyst formed easily at 873 K in the presence of a CH4/02/Ar (2/1/45, molar) mixture and that the dominant pathway to synthesis gas was by the sequence of total oxidation of CH4 followed by reforming of the unconverted CH4 by C02 and H20. Thus, these results indicate that the oxidation of methane takes place principally by the combustion mechanism on the oxidized form of this catalyst. 

Temperature-Programmed Surface Reaction (TPSR) Experiments at 800 Torr. Pretreated and preoxidized silver exhibited no reactivity toward an ethylene/argon mixture at reaction temperatures (443 - 543 K) and atmospheric pressures (750-800 torr). The desorption spectrum of a pretreated sample showed no evidence of oxygen desorption when the sample was heated in vacuo to 673 K. These... 

Temperature-programmed surface reaction (TPSR). Measurements were performed in a flow apparatus with a BALZERS quadrupolar mass spectrometer to monitor effluent products versus temperature. Samples of 300 mg were used in each measurement. The gases employed were He (99.9%) and mixtures 4% NH3/He, 1% NO/He and 5% 02/He. TPSR measurements were obtained after NH3 adsorption at 70°C under continuous flow until base line stabilization. The reactor was heated to 500°C at 20°C/min and kept at this... 

The nature of the carbon deposits formed on an alumina-supported nickel catalyst have been characterized by their reactivity with H2 and H 0 during temperature-programmed surface reaction (TPSR). 

In a previous study (9 ) we used temperature-programmed surface reaction (TPSR) with 1 atm hydrogen to determine the... 

In this contribution, we present computer analyses of several selected temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR) experiments in a microreactor flow system operating under atmospheric pressure. The continuous stirred tank reactor (CSTR) and plug flow reactor (PFR) models have been applied for the design equation as... 

Fastrup et al. [9] presented a detailed experimental study of the hydrogenation of an iron-based surface precovered with atomic nitrogen using the temperature-programmed surface reaction (TPSR) method. Their modeling results clearly demonstrate the effect of the initial coverage of N- and the effect of the H2 partial pressure. The kinetic mechanism of the TPSR experiment can be written as depicted below. 

The temperature-programmed surface reaction (TPSR) experiment was carried out in a quartz-made microreactor connected to a thermal conductivity detector (TCD) equipped with active charcoal column using 0.2 g passivated catalysts. The passivated catalysts were reduced by hydrogen at 673 K for 1 h, and then... 

Isopropanol chemisorption and temperature programmed surface reaction (TPSR) towards propylene allowed the determination of the number of active acid sites and the activation energy in order to compare the acid properties of HPAs with various catalytic materials. 

TPAT technologies include temperature programmed desorption (TPD), temperature programmed reduction (TPR), temperature programmed oxidation (TPO), temperature programmed sulfide (TPS), temperature programmed surface reaction (TPSR) and so on. TPD is the most extensively studied, widely applied and the most mature method. Hence, TPD will be focused in the following section. 

Moreover, the application of oxygen chemisorption techniques assumes that reduced surface transition metal species are responsible for the catalytic activity [4], However, detailed investigation through successive cycles of reactant adsorption and temperature programmed surface reaction (TPSR) without reoxidation of the surface showed the deactivation of molybdenum and vanadium oxide-based catalysts upon reduction [9]. These results clearly indicate that oxidized surface metal oxide species are the active surface sites to be investigated. 

Activation processes-reduction and sulfidation Temperature programmed surface reaction (TPSR)... 

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