We determine absolute reactivities for dissociation at low coordinated Pt sites. Two curved Pt(111) single‐crystal surfaces allow us to probe either straight or highly kinked step edges with molecules impinging at a low impact energy. A model extracts the average reactivity of inner and outer kink atoms, which is compared to the reactivity of straight A‐ and B‐type steps. Local surface coordination numbers do not adequately capture reactivity trends for H2 dissociation. We utilize the increase of reactivity with step density to determine the area over which a step causes increased dissociation. This step‐type specific reactive area extends beyond the step edge onto the (111) terrace. It defines the reaction cross‐section for H2 dissociation at the step, bypassing assumptions about contributions of individual types of surface atoms. Our results stress the non‐local nature of H2 interaction with a surface and provide insight into reactivity differences for nearly identical step sites.
We determine absolute reactivities for dissociation at low coordinated Pt sites. Two curved Pt(111) single‐crystal surfaces allow us to probe either straight or highly kinked step edges with molecules impinging at a low impact energy. A model extracts the average reactivity of inner and outer kink atoms, which is compared to the reactivity of straight A‐ and B‐type steps. Local surface coordination numbers do not adequately capture reactivity trends for H2 dissociation. We utilize the increase of reactivity with step density to determine the area over which a step causes increased dissociation. This step‐type specific reactive area extends beyond the step edge onto the (111) terrace. It defines the reaction cross‐section for H2 dissociation at the step, bypassing assumptions about contributions of individual types of surface atoms. Our results stress the non‐local nature of H2 interaction with a surface and provide insight into reactivity differences for nearly identical step sites.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.