Reduction of N2O on MgO/Ag(100) via UV-Photoinduced Trapped Electrons
Reduction of N2O on MgO/Ag(100) via UV-Photoinduced Trapped Electrons
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DOI：
10.1021/jp109385s
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发表时间：
2011-05
影响因子：
3.7
通讯作者：
P. Giese;H. Kirsch;M. Wolf;C. Frischkorn
中科院分区：
文献类型：
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作者：
P. Giese;H. Kirsch;M. Wolf;C. Frischkorn
利用辐射后热解吸光谱（TDS）研究了在Ag（100）晶体上生长的MgO薄膜上N2O在光子驱动下的解离。在248 nm光子激发后，我们观察到N2和高温氧同时形成，同时伴随着母体N2O信号的减弱。根据N2和N2O的产生和消耗作为光子剂量的函数，我们分别确定了大约10-18和10-19 cm2的截面，而对于N2光产物的同时解吸，我们发现了10-20 cm2的截面。如果在650 K时完成分子氧的解吸，则MgO膜实际上恢复到其初始反应状态。然而，在随后的还原循环中，高温氧的部分去除导致N2的形成减少，我们通过在不够高的退火温度下通过氧阻断反应位点来解释这一点。我们的findi…
The photon-driven substrate-mediated dissociation of N2O on thin MgO films grown on an Ag(100) crystal has been investigated with postirradiation thermal desorption spectroscopy (TDS). After excitation with 248 nm photons, we observe the simultaneous formation of N2 and a high-temperature oxygen species, accompanied by a decrease in the parent N2O signal. On the basis of the generation and depletion of N2 and N2O as a function of the photon dose, we determine cross sections of about 10–18 and 10–19 cm2, respectively, whereas for the concurrent desorption of the N2 photoproduct a cross section of 10–20 cm2 is found. If the desorption of molecular oxygen is completed at 650 K, then the MgO film is virtually restored to its initial reactivity condition. However, only partial removal of the high-temperature oxygen results in the diminished formation of N2 in subsequent reduction cycles, which we explain by blocking the reactive sites through oxygen at annealing temperatures that are not high enough. Our findi...