Mo(001)表面的CaO(001)薄膜模型催化体系的STM研究

氧化物单晶化薄膜的制备与表征是研究氧化物表面性质的重要方法，也是模型催化研究的前沿领域。本文主要综述了Fritz-Haber研究所的Hajo Freund小组在过去几年间围绕着以Mo(001)为衬底制备的CaO(001)薄膜模型催化体系而进行的表面结构和化学性质的系列研究。其中既包含了氧化物薄膜研究的共同特点，如界面效应、膜厚效应等，也包含有CaO/Mo体系独特的性质，如Mo的自发掺杂对表面性质的调控作用。在该系列研究中低温扫描隧道显微镜(LT-STM)技术的应用贯穿了方方面面，从原子结构表征到电子性质研究，从杂质缺陷的鉴别到表面物种荷电性质的分析等。STM所获得的微观信息直接从原子分子水平揭示了调控薄膜表面性质的各种控因。特别的，在理论计算的辅助下，不断深化认识氧化物掺杂调控的原理和机制，为设计新型催化剂提供重要思路。

STM Study of CaO(001) Model Catalytic Thin Films Prepared on Mo(001) Surface

Single crystalline oxide thin film has been delegated as an important approach to studying oxide materials. The related researches are at the frontier of model catalysis. In this review, we try to summarize what has been researched so far around the CaO(001) films, which have been recently developed in Prof. Hajo Freund′s group at the Fritz-Haber Institute. The revealed properties of CaO films have displayed the common characteristics of supported ultrathin oxide films, which are sensitively dependent on the interface structures and film thicknesses, but they have also shown new aspects such as the novel tuning effects from self-doping by substrate ions. Low-temperature scanning tunneling microscopy (LT-STM) has been applied through all detailed studies, including the characterizations of atomic structure and electronic properties, recognition of various defects and charge analyses of various surface species. The microscopic information received from delicate STM measurements provides atomic views of the effective factors involved in manipulating the oxide surface properties. With the aid of theoretical calculations, deep insights of the doping mechanism and selection principles of the dopants are achieved, which should largely assist the design of new catalysts.