Lu Qiyang
School of Engineering and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, P. R. China.
ACS Nano. 2024 Jun 4;18(22):13973-13982. doi: 10.1021/acsnano.4c03964. Epub 2024 May 22.
Nanomaterials based on transition-metal oxides (TMOs) that contain late 3d transition metals (e.g., Mn, Fe, Co, Ni) have diverse properties and functionality that are related to the oxidation state of constituent transition-metal (TM) cations. X-ray photoelectron spectroscopy (XPS) of TM 2p orbitals has been widely used to quantify the TM oxidation state of TMOs. However, 2p XPS spectra of late 3d TM cations usually have complicated shapes due to the charge transfer between the TM cation and oxygen ligands (anions), which makes the analysis highly nontrivial. In this article, we will examine the validity of commonly used analysis methods based on either peak fitting or the shift of binding energy (BE). The different origins of the BE shift in XPS spectra will be discussed. We will then introduce a model to reproduce the complex shapes of TM 2p spectra, based on fundamental parameters that describe the TMO electronic structure.
基于包含晚期3d过渡金属（如Mn、Fe、Co、Ni）的过渡金属氧化物（TMO）的纳米材料具有与组成过渡金属（TM）阳离子的氧化态相关的多种性质和功能。TM 2p轨道的X射线光电子能谱（XPS）已被广泛用于量化TMO的TM氧化态。然而，由于TM阳离子与氧配体（阴离子）之间的电荷转移，晚期3d TM阳离子的2p XPS光谱通常具有复杂的形状，这使得分析极具挑战性。在本文中，我们将研究基于峰拟合或结合能（BE）位移的常用分析方法的有效性。将讨论XPS光谱中BE位移的不同起源。然后，我们将引入一个模型，基于描述TMO电子结构的基本参数来重现TM 2p光谱的复杂形状。
