CAJ | 학술논문

采用扫描隧道显微镜和X射线光电子能谱对含有次表层Fe的Pt表皮结构(Pt skin),即0.4MLFe的Pt/Fe/Pt(111)表面,在1.1×10-7kPa氧气气氛退火过程中的变化进行了研究.结果表明,当退火温度为600K时,氧气在Pt/Fe/Pt(111)表面上解离吸附并诱导表面局域结构的重构;750K时次表层Fe可以扩散到表面并被氧化;当升至850K时,在样品表面形成单层FeO结构,并且FeO表面具有周期性的缺陷.这种缺陷是由于单层FeO薄膜的摩尔条纹单胞中fcc位上一个或多个氧原子缺失形成的,其中多原子空位被确定为缺失6个氧原子所致.FeO表面缺陷结构的研究为理解Fe-Pt催化剂在氧化气氛中的结构稳定性以及构造表面活性位提供一定的基础.
채용소묘수도현미경화X사선광전자능보대함유차표층Fe적Pt표피결구(Pt skin),즉0.4MLFe적Pt/Fe/Pt(111)표면,재1.1×10-7kPa양기기분퇴화과정중적변화진행료연구.결과표명,당퇴화온도위600K시,양기재Pt/Fe/Pt(111)표면상해리흡부병유도표면국역결구적중구;750K시차표층Fe가이확산도표면병피양화;당승지850K시,재양품표면형성단층FeO결구,병차FeO표면구유주기성적결함.저충결함시유우단층FeO박막적마이조문단포중fcc위상일개혹다개양원자결실형성적,기중다원자공위피학정위결실6개양원자소치.FeO표면결함결구적연구위리해Fe-Pt최화제재양화기분중적결구은정성이급구조표면활성위제공일정적기출.
The structural evolution of a Pt surface with 0.4 monolayer (ML) subsurface Fe on annealing in 1.1 × 10-7 kPa O2 was studied by scanning tunneling microscopy and X-ray photoelectron spectroscopy. When the annealing temperature was 600 K, only dissociative adsorption of O2 occurred, which induced the local restructuring of surface regions. At 750 K, subsurface Fe atoms segregated onto the surface and were oxidized. When the annealing temperature was increased to 850 K, well defined monolayer FeO islands with periodic arrays of defects vacancies or multiple oxygen vacancies consisting of six missing O atoms. The formation of periodic defects on monolayer FeO islands may be a way to construct active sites on Pt-Fe model catalysts.