Low temperature complete combustion of dilute methane over Mn-doped ZrO2 catalysts:: factors influencing the reactivity of lattice oxygen and methane combustion activity of the catalyst
Low temperature complete combustion of dilute methane over Mn-doped ZrO2 catalysts:: factors influencing the reactivity of lattice oxygen and methane combustion activity of the catalyst
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DOI：
10.1016/s0926-860x(01)00925-5
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发表时间：
2002-03-08
影响因子：
5.5
通讯作者：
Pataskar, SG
中科院分区：
文献类型：
--
作者：
Choudhary, VR;Uphade, BS;Pataskar, SG
研究了不同Mn/Zr摩尔比（0-1.0）的Mn掺杂zro(2)催化剂在不同温度（400-600℃）和空速(51,000- 150000 cm(3) g（-1) h(-1)）和Mn浸透ZrO2上的甲烷（1.0 vol.%）完全燃烧。采用程序升温还原法（TPR）和程序升温还原法（TPRLOM）研究了催化剂的晶格氧在100 ~ 600℃范围内与纯甲烷的反应活性。这种反应性由于在ZrO2中掺杂锰而急剧增加，特别是当所得催化剂呈立方形式时。随着Mn/Zr比从0到1.0的增加，催化剂的甲烷燃烧活性先增加后达到最大值，在Mn/Zr比为0.25左右时活性最大。类似的趋势还观察到催化剂表面积的变化，ZrO2在立方形态下的稳定，以及TPR峰（在高温下）向低温侧的移动，这表明晶格氧的反应活性和/或迁移性更高。然而，当Mn掺杂ZrO2（立方，Mn/Zr = 0.25）的煅烧温度从500℃升高到800℃时，其表面积不断减小，但其甲烷燃烧活性在600℃时达到最大值，其立方形态也在800℃时转变为单斜和立方混合形态。(C) 2002 Elsevier Science B.V.版权所有
Complete combustion of methane (1.0 vol.% in air) over Mn-dopedZrO(2) catalysts with different Mn/Zr mole ratios (0-1.0) at different temperatures (400-600degreesC) and space velocities (51,000-150,000 cm(3) g(-1) h(-1)) and also over Mn-impregnated ZrO2 have been thoroughly investigated. Reactivity of the lattice oxygen of the catalysts was studied by temperature-programmed reduction (TPR) with H-2 and also by the temperature-programmed reaction of lattice oxygen with pure methane (TPRLOM), both from 100 to 600degreesC. Such reactivity is drastically increased due to the doping of Mn in ZrO2, particularly when the resulting catalyst is in cubic form. The methane combustion activity of the catalyst is first increased, passes through a maximum and then decreases with increasing the Mn/Zr ratio from 0 to 1.0, the maximum activity was observed for the Mn/Zr ratio of about 0.25. Similar trends were also observed for the variation of the catalyst surface area, stabilization of ZrO2 in its cubic form and also for the shift in the TPR peak (at higher temperatures) towards the lower temperature side, indicating higher reactivity and/or mobility of the lattice oxygen. However, when the calcination temperature of the Mn-doped ZrO2 (cubic, Mn/Zr = 0.25) is increased from 500 to 800degreesC, its surface area is decreased continuously, but its methane combustion activity passed through a maximum at the calcination temperature of 600degreesC, its cubic form is also converted into a mixed monoclinic and cubic form at 800degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.