N2O decomposition over CuO/CeO2 catalyst: New insights into reaction mechanism and inhibiting action of H2O and NO by operando techniques
N2O decomposition over CuO/CeO2 catalyst: New insights into reaction mechanism and inhibiting action of H2O and NO by operando techniques
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DOI：
10.1016/j.apcatb.2016.02.024
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发表时间：
2016-11
影响因子：
22.1
通讯作者：
Maxim Zabilskiy;P. Djinović;E. Tchernychova;A. Pintar
中科院分区：
文献类型：
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作者：
Maxim Zabilskiy;P. Djinović;E. Tchernychova;A. Pintar
在这项工作中，结合原位（STEM-EELS, STEM-EDX， H2-TPR和XPS），原位（CO-DRIFTS）和operando（DR UV-vis和DRIFTS）方法来探测活性位点，并确定N2O在高活性4 wt.% Cu/ ceo2催化剂上分解的机制。此外，还确定了NO和H2O存在下催化剂失活的反应途径。结果表明，[Cu−O−Cu]2+位点在催化N2O分解途径中起关键作用。由于暴露于{10 0}和{11 10 0}高能表面，纳米棒状ceo2载体通过Ce3+/Ce4+氧化还原对的存在，同时表现出CuO/ ceo2氧化还原性能的增强。其主要作用是通过分子氧的重组和解吸来实现双核Cu+位点再生，同时其少量的活性参与了N2O的直接分解。NO和H2O对N2O分解反应的抑制作用完全不同。水分子与ceo2的氧空位位点强烈离解结合，阻止进一步的氧转移和催化剂活性位点的再生。另一方面，NO的作用通过竞争氧化为NO2来表达，NO2消耗了ceo2中的不稳定氧，减缓了[Cu+Cu+]活性位点的再生。
In this work, a combination ofex situ(STEM-EELS, STEM-EDX, H2-TPR and XPS),in situ(CO-DRIFTS) andoperando(DR UV–vis and DRIFTS) approaches was used to probe the active sites and determine the mechanism of N2O decomposition over highly active 4 wt.% Cu/CeO2catalyst. In addition, reaction pathways of catalyst deactivation in the presence of NO and H2O were identified. The results ofoperandoDR UV–vis spectroscopic tests suggest that [Cu−O−Cu]2+sites play a crucial role in catalytic N2O decomposition pathway. Due to exposure of {1 0 0} and {1 1 0} high-energy surface planes, nanorod-shaped CeO2support simultaneously exhibits enhancement of CuO/CeO2redox properties through the presence of Ce3+/Ce4+redox pair. Its dominant role of binuclear Cu+site regeneration through the recombination and desorption of molecular oxygen is accompanied by its minor active participation in direct N2O decomposition. NO and H2O have completely different inhibiting action on the N2O decomposition reaction. Water molecules strongly and dissociatively bind to oxygen vacancy sites of CeO2and block further oxygen transfer as well as regeneration of catalyst active sites. On the other hand, the effect of NO is expressed through competitive oxidation to NO2, which consumes labile oxygen from CeO2and decelerates [Cu+Cu+] active site regeneration.