Site-specific reactivity of oxygen at Cu(110) step defects: An STM study of ammonia dehydrogenation

[摘要] Defects on surfaces, such as steps, are known to influence catalytic activity considerably, but few microscopic observations have been made of such site-specific reactivity. Using atomic-resolution scanning tunneling microscopy (STM), we have observed the reactivity of oxygen adsorbed in the (2 x 1) structure at step sites on the Cu(110) surface with ammonia. It is found that the reactivity is high at both the top and bottom of a [1 (1) over bar 0] step and at the bottom of a [001] step, whereas almost no reaction occurs at the sites bordering the top of a [001] step. Reaction at the bottom of [001] steps appears to lead to deposition of copper atoms at the step edge.

[发布日期] 1996-12-01

[关键词] adsorption kinetics;ammonia;atom-solid reactions;catalysis;copper;low index single crystal surfaces;models of surface kinetics;oxygen;scanning tunneling microscopy;surface chemical reaction