In situ STM imaging of ammonia oxydehydrogenation on Cu(110): the reactivity of preadsorbed and transient oxygen species

SURFACE SCIENCE

卷:387

Article

Guo, XC ; Madix, RJ

关键词: ammonia;    Cu(110);    oxidation;    oxygen;    scanning tunneling microscopy;    surface chemical reactions;   

DOI  :  10.1016/S0039-6028(97)00158-1

来源: Elsevier

【 摘 要 】

Dissociative adsorption of oxygen on Cu(110) forms isolated, added -Cu-O- rows at low coverages and p(2 x 1)-O islands at high coverages. The reactivity of both types of species for ammonia oxydehydrogenation has been investigated quantitatively by in situ imaging with an atomic-resolution scanning tunneling microscope. We find that oxygen in both forms is reactive with ammonia. At low coverages all oxygen adatoms are consumed readily, while at high precoverages reaction proceeds from the boundaries of oxygen islands. Though the reaction can be initiated from both the end and the side of the -Cu-O- rows, the reactivity appears to be anisotropic, being higher along the [001] direction. The reactivity of transient oxygen species formed during the exposure of the surface to a mixture of ammonia and oxygen is estimated to be comparable to that of the reactivity of preadsorbed oxygen at low coverages. (C) 1997 Elsevier Science B.V.

【 授权许可】

Free