N2O decomposition over K-promoted Co-Al catalysts prepared from hydrotalcite-like precursors
N2O decomposition over K-promoted Co-Al catalysts prepared from hydrotalcite-like precursors
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DOI：
10.1016/j.apcatb.2008.12.018
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发表时间：
2009-07
影响因子：
22.1
通讯作者：
Hongkui Cheng;Yanqiang Huang;Aiqin Wang;Lin Li;Xiaodong Wang;Tao Zhang
中科院分区：
文献类型：
--
作者：
Hongkui Cheng;Yanqiang Huang;Aiqin Wang;Lin Li;Xiaodong Wang;Tao Zhang
在一系列 K 促进的 Co-Al 催化剂上研究了 N2O 分解。活性测试表明，K的掺杂极大地增强了Co-Al催化剂的催化活性，并且增强效果关键取决于K的量和煅烧温度。当催化剂的K/Co原子比为0.04并在700-800℃下煅烧时，在300℃的反应温度下可以达到完全的N2O转化。此外，即使在4％O2和2.6％水蒸气同时存在的情况下，这种高温处理的K/Co-Al催化剂也表现出高反应活性和稳定性，在360℃运行40小时内N2O转化率保持在92％的恒定值。相比之下，未掺杂的Co-Al催化剂在这种反应条件下表现出严重的活性损失。采用表征技术的组合来揭示 K 的促进作用和煅烧温度的影响。结果表明，K掺杂增加了Co的电子密度，削弱了Co-O键，从而促进了Co位点上N2O的活化，并促进了氧从催化剂表面的解吸。高温煅烧使得O2的解吸更容易进行。
N2O decomposition was investigated over a series of K-promoted Co-Al catalysts. The activity tests showed that doping with K greatly enhanced the catalytic activity of the Co-Al catalyst, and the enhancement was critically dependent on the amount of K and the calcination temperature. When the catalyst had a K/Co atomic ratio of 0.04 and was calcined at 700–800°C, a full N2O conversion could be reached at a reaction temperature of 300°C. Moreover, even under the simultaneous presence of 4% O2and 2.6% water vapor, such high-temperature treated K/Co-Al catalyst exhibited high reactivity and stability, with the N2O conversion remaining at a constant value of 92% over 40h run at 360°C. In contrast, non-doped Co-Al catalyst showed a severe activity loss under such reaction conditions. A combination of characterization techniques was employed to reveal the promoting role of K and the effect of calcination temperature. The results suggest that doping with K increases the electron density of Co and weakens the Co–O bond, thus promoting the activation of N2O on the Co sites and facilitating the desorption of oxygen from the catalyst surface. High-temperature calcinations made the desorption of O2proceed more readily.