A Space-Charge Treatment of the Increased Concentration of Reactive Species at the Surface of a Ceria Solid Solution.
A Space-Charge Treatment of the Increased Concentration of Reactive Species at the Surface of a Ceria Solid Solution.
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DOI：
10.1002/anie.201708118
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发表时间：
2017-11
影响因子：
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通讯作者：
A. Zurhelle;X. Tong;A. Klein;D. Mebane;R. D. De Souza
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文献类型：
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作者：
A. Zurhelle;X. Tong;A. Klein;D. Mebane;R. D. De Souza
适用于浓固溶体的空间电荷理论（Poisson-Cahn理论）被施加到定量描述作为温度和氧分压的函数发表的数据通过原位X射线光电子能谱（XPS）获得的浓度Ce 3+（活性物种）在氧化物催化剂Ce0.8 Sm0.2 O1.9的表面。与以前的理论处理相反，这些计算清楚地表明，表面是带正电的，并通过伴随的负空间电荷区进行补偿。在表面处产生的高空间电荷电位（> 0.8V）被证明是难以通过XPS测量检测到的，因为空间电荷层的范围短。这种方法强调需要考虑到缺陷的相互作用，并允许偏离局部电荷中性时，考虑氧化物催化剂的表面。
A space-charge theory applicable to concentrated solid solutions (Poisson-Cahn theory) was applied to describe quantitatively as a function of temperature and oxygen partial pressure published data obtained by in situ X-ray photoelectron spectroscopy (XPS) for the concentration of Ce3+ (the reactive species) at the surface of the oxide catalyst Ce0.8 Sm0.2 O1.9 . In contrast to previous theoretical treatments, these calculations clearly indicate that the surface is positively charged and compensated by an attendant negative space-charge zone. The high space-charge potential that develops at the surface (>0.8 V) is demonstrated to be hardly detectable by XPS measurements because of the short extent of the space-charge layer. This approach emphasizes the need to take into account defect interactions and to allow deviations from local charge neutrality when considering the surfaces of oxide catalysts.