Deactivation of high temperature combustion catalysts

Thévenin, Philippe; Ersson, Anders; Kušar, Henrik; Menon, P.G.; Järås, Sven

doi:10.1016/s0926-860x(00)00846-2

Cited by 43 publications

(19 citation statements)

References 41 publications

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“…But, the deactivation of catalysts is an important issue for the design of a commercial catalytic system for such a high temperature reaction. Poisoning, sintering, coking or fouling are reported as causes of the catalyst deactivation [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Pd/α-Si3N4 Catalysts Through the Solvent Used During Synthesis. Implications on the CO Chemisorption Properties and Catalytic Performances

2009

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Palladium catalysts supported on a-Si 3 N 4 were prepared by impregnation with Pd(II)-acetate dissolved either in toluene or in water. The mean metal particle size of *0.5 wt% Pd catalysts was similar (*5 nm) and independent of the way of preparation. Nevertheless, the two catalysts present very different chemisorption behaviour chemisorptive and catalytic properties. Fourier transformed infrared (FTIR) spectra of adsorbed CO at different temperatures (ranging from room temperature to 300°C) show a very different behaviour for both catalysts. While the CO adsorption states on the Pd/a-Si 3 N 4 prepared in toluene are very similar to those generally measured for silica and/or alumina supported palladium catalysts, CO chemisorbs less strongly on Pd/a-Si 3 N 4 prepared in water and on different adsorption sites. The Pd/a-Si 3 N 4 catalyst obtained by aqueous impregnation is much less efficient for the methane total oxidation. It is less active and less stable: it deactivates strongly after 3 h on stream at 650°C. The two catalysts present about the same activity for the 1,3-butadiene hydrogenation after stabilisation at 20°C. But, the catalyst prepared in water shows a much better selectivity to butenes. The results are discussed in terms of the possible migration of silicon atoms from the silicon nitride support to the surface of the palladium particles, when the catalyst is prepared in water. This is not the case when prepared in an organic solvent.

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Section: Introductionmentioning

confidence: 99%

Surface Modification of Pd/α-Si3N4 Catalysts Through the Solvent Used During Synthesis. Implications on the CO Chemisorption Properties and Catalytic Performances

2009

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“…Nevertheless, there remains a major problem for the application of catalytic combustion unsettled, namely, the scarcity of robust and stable catalysts for catalytic combustion under severe hydrothermal conditions [13,14]. Extensive efforts have been made to develop suitable catalysts and overcome these key obstacles for commercial applications.…”

Section: Introductionmentioning

confidence: 99%

Catalytic combustion of methane on novel catalysts derived from Cu-Mg/Al-hydrotalcites

Jiang

Hao

et al. 2005

Catal Lett

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Novel Cu-Mg/Al mixed oxides (designated as i-CMAO-800) were prepared by calcinations of Cu-Mg/Al-hydrotalcites [(Cu 2þ +Mg 2þ )/Al 3þ = 3] at 800 C. Their performance for the catalytic combustion of methane was investigated. The oxides and their precursors were characterized by XRD, TG-DSC, TPR and N 2 adsorption/desorption techniques. The results showed that BET surface areas and the stability of the resultant oxides were greatly influenced by the copper contents in hydrotalcite precursors, bringing about difference in their activities for methane catalytic combustion. XRD results indicated that Cu was highly dispersed in hydrotalcite precursors in case of low copper contents, (Cu 40 wt%). For higher Cu contents, Cu(OH) 2 was formed, and, consequently, a separate phase of CuO was detected in the oxide catalysts after calcination. As indicated by the TG-DSC results, different decomposition behaviors were observed for various hydrotalcites. Thermal calcination promoted the formation of copper aluminates and segregation of CuO from the bulk phases. TPR results showed 15CMAO-800 has the highest reduction rate, and the catalytic activities of iCMAO-800 mixed oxides depend on both the reduction rates and the amounts of copper ions in mixed oxides. The catalyst 15-CMAO-800 showed the best performance.

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“…For the effective and stable catalytic combustion process, suitable catalysts play a crucial role. Generally, supported noble metal oxides, particularly palladium oxide, are excellent catalysts for lower temperature combustion, but noble metals are expensive and prone to deactivation owing to sintering, decomposition and undesirable interaction with supports under hydrothermal situations encountered in combustion [3,6,[8][9][10]. A variety of inexpensive transition metal oxide catalysts, such as solid solution oxides [11][12][13], perovskites [14][15][16], pyrochlores [17][18][19] and hexaaluminates [7,[20][21][22] have been explored for catalytic combustion of methane.…”

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confidence: 99%

Catalytic combustion of methane over mixed oxides derived from Co–Mg/Al ternary hydrotalcites

Jiang

Cheng

et al. 2010

Fuel Processing Technology

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Co x Mg 3 − x /Al composite oxides (xCoMAO-800) were prepared by calcination of Co x Mg 3 − x /Al hydrotalcites (x = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, respectively) at 800°C. The materials were characterized using XRD, TG-DSC, N 2 adsorption-desorption and TPR. The methane catalytic combustion over the xCoMAO-800 was assessed in a fixed bed micro-reactor. The results revealed that cobalt can be homogenously dispersed into the matrices of the hydrotalcites and determines the structure, specific surface areas and porosity of the derived xCoMAO-800 oxide catalysts. The thermal stability and homogeneity of the hydrotalcites markedly depends on the cobalt concentration in the hydrotalcites. The Co-based hydrotalcite-derived oxides exhibit good activity in the catalytic combustion of methane. The catalytic activity over the xCoMAO-800 oxides enhances with increasing x up to 1.5, but subsequently decreases dramatically as cobalt loadings are further increased. The 1.5CoMAO-800 catalyst shows the best methane combustion activity, igniting methane at 450°C and completing methane combustion around 600°C. The catalytic combustion activity over the xCoMAO-800 oxides are closely related to the strong Co-Mg/Al interaction within the mixed oxides according to the TG-DSC, TPR and activity characteristics.© 2009 Elsevier B.V. All rights reserved.The catalytic combustion of methane has attracted intensive interests in the past few decades, due to its higher energy conversion efficiency and ultra-low emissions of environmental pollutants, such as NO x , CO, and unburned hydrocarbons [1][2][3][4][5][6]. In addition, catalytic combustion of lean methane gas to abate methane emission also has wide-ranging applications [5,7]. For the effective and stable catalytic combustion process, suitable catalysts play a crucial role. Generally, supported noble metal oxides, particularly palladium oxide, are excellent catalysts for lower temperature combustion, but noble metals are expensive and prone to deactivation owing to sintering, decomposition and undesirable interaction with supports under hydrothermal situations encountered in combustion [3,6,[8][9][10]. A variety of inexpensive transition metal oxide catalysts, such as solid solution oxides [11][12][13], perovskites [14][15][16], pyrochlores [17][18][19] and hexaaluminates [7,[20][21][22] have been explored for catalytic combustion of methane. Unfortunately, no single catalyst, so far, can tolerate the stringent hydrothermal conditions existing in methane combustion. Obviously, the further development of new combustion catalysts is indispensable. Currently, multi-staged combustion methodology are used to overcome the drawbacks of the current catalysts for catalytic combustion [2,3], in which the catalysts of high surface area and activity are highly desired to ignite methane at lower temperatures and sustain stable combustion at high temperatures.Among the transition metal oxide catalysts, cobalt-based oxides are ones of the most active catalysts in catalytic methane combustion, and Co...

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Deactivation of high temperature combustion catalysts

Cited by 43 publications

References 41 publications

Surface Modification of Pd/α-Si3N4 Catalysts Through the Solvent Used During Synthesis. Implications on the CO Chemisorption Properties and Catalytic Performances

Surface Modification of Pd/α-Si3N4 Catalysts Through the Solvent Used During Synthesis. Implications on the CO Chemisorption Properties and Catalytic Performances

Catalytic combustion of methane on novel catalysts derived from Cu-Mg/Al-hydrotalcites

Catalytic combustion of methane over mixed oxides derived from Co–Mg/Al ternary hydrotalcites

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