NONUNIFORM PRODUCT INHIBITION IN SURFACE-REACTIONS - SPATIAL-ORGANIZATION EFFECTS IN AMMONIA OXYDEHYDROGENATION ON CU(110)

Ammonia reacts with Cu(100)p(2 x 1)O between 300 and 400 K to form hig hly spatially organized co-adsorbed layers of O(a), NH(a) and N(a). No ne of the initially adsorbed oxygen appears inherently unreactive, tho ugh the reactivity of oxygen does depend on its local structural envir onment. Both NH(a) and N(a) form linear structures along the [1(1) ove r bar0$ 0] direction, perpendicular to the added Cu-O rows of the (2 x 1) structure. In many cases these nitrogen-induced features block the ends of the Cu-O rows and appear to retard further reaction. As a res ult of such interactions, structures are formed that render otherwise isolated, short reactive Cu-O rows unreactive.