Structure-sensitive reactivities of O/Cu(100) studied by in situ NAP-STM

As the reactivities of materials originate essentially from the microstructures presenting on surface, the microscopic insight of structure -sensitive reactivity is crucial to understanding the nature of catalytic reactions. Herein, we have shown that both the structural evolution and the reactivity towards CO of O/Cu(1 0 0) exhibit remarkable structural sensitivity. Oxygen adsorbed on Cu(1 00) readily dissociate to oxygen dimers with gradually transforming to disordered c(2 x 2) structure (DCS). The DCS is further crystallized to missing -row reconstruction (MRR) structure preferentially at step edges prior to the presence of MRR and single -atom -high islands (SAHIs) on terraces. The DCS surrounding SAHI exhibits the highest reactivity towards CO through the enhanced CO adsorption and suitable geometric matching. At higher CO pressure, DCS and MRR react preferentially from step edges, followed by the DCS on terraces. Comparatively, isolated MRR shows unusual inertness due to the lack of microstructure that can trigger an initial reduction.