The surface structure of Fe3O4(111) films as studied by CO adsorption
The surface structure of Fe3O4(111) films as studied by CO adsorption
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DOI：
10.1016/j.susc.2004.08.033
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发表时间：
2004-11-10
期刊：
影响因子：
1.9
通讯作者：
Freund, HJ
中科院分区：
文献类型：
--
作者：
Lemire, C;Meyer, R;Freund, HJ
用程序升温脱附（TPD）、红外反射吸收谱（IRAS）和高分辨电子能量损失谱（HREELS）研究了CO在Pt（111）衬底上生长的Fe_3O_4（111）薄膜上的吸附。在110、180和230 K时，CO从吸附态中脱附。CO在这三种吸附态下的伸缩振动频率分别为2115 -2140、2080和2207 cm（-1）。吸附结果进行了讨论，在不同的结构模型以前报道。我们认为Fe_3O_4（111）表面由1/2 ML的铁终止，最外面的1/4 ML由八面体Fe ~（2+）阳离子组成，位于四面体Fe ~（3+）离子的1/4 ML之上，与以前的理论计算一致。最强烈的绑定CO被分配到吸附Fe 3+阳离子上存在的步骤边缘。(C)2004 Elsevier B. V.保留所有权利。
We have studied adsorption of CO on Fe3O4(111) films grown on a Pt(111) substrate by temperature programmed desorption (TPD), infrared reflection absorption spectroscopy (IRAS) and high resolution electron energy loss spectroscopy (HREELS). Three adsorption states are observed, from which CO desorbs at similar to110, 180, and 230 K. CO adsorbed in these states exhibits stretching frequencies at similar to2115-2140, 2080 and 2207cm(-1), respectively. The adsorption results are discussed in terms of different structural models previously reported. We suggest that the Fe3O4(111) surface is terminated by 1/2 ML of iron, with an outermost 1/4 ML consisting of octahedral Fe2+ cations situated above an 1/4 ML of tetrahedral Fe3+ ions, in agreement with previous theoretical calculations. The most strongly bound CO is assigned to adsorption to Fe3+ cations present on the step edges. (C) 2004 Elsevier B.V. All rights reserved.