Wang Jianyu, Li Chaoran, Zhu Yaguang, Boscoboinik Jorge Anibal, Zhou Guangwen
Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York at Binghamton, Binghamton, New York 13902, United States.
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States.
J Phys Chem Lett. 2022 Jun 23;13(24):5597-5604. doi: 10.1021/acs.jpclett.2c00988. Epub 2022 Jun 14.
Using ambient-pressure X-ray photoelectron spectroscopy and Auger electron spectroscopy to monitor the reduction of CuO in H, we identify the formation of an intermediate, oxygen-deficient CuO phase and its progressive inward growth into the deeper region of the oxide. Complemented by atomistic modeling, we show that the oxygen-deficient CuO formation occurs via molecular H adsorption at the CuO surface, which results in the loss of lattice oxygen from the formation of HO molecules that desorb spontaneously from the oxide surface. The resulting oxygen-deficient CuO is a stable intermediate that persists before the CuO is fully reduced to metallic Cu. The oxygen vacancy-induced charge of the coordinating Cu atoms results in a satellite feature in Cu LMM, which can be used as a fingerprint to identify nonstoichiometry in oxides and local charge transfer induced by the nonstoichiometry.
利用常压X射线光电子能谱和俄歇电子能谱监测氢气中氧化铜的还原过程，我们确定了一种中间产物——缺氧氧化铜相的形成及其向氧化物更深区域的逐步向内生长。通过原子模型的补充，我们表明缺氧氧化铜的形成是通过分子氢在氧化铜表面的吸附发生的，这导致了从自发从氧化物表面解吸的水分子形成过程中晶格氧的损失。生成的缺氧氧化铜是一种稳定的中间产物，在氧化铜完全还原为金属铜之前一直存在。配位铜原子的氧空位诱导电荷在铜LMM中产生一个卫星特征，可作为识别氧化物中非化学计量和由非化学计量引起的局部电荷转移的指纹。
