title: Roles of surface steps on Pt nanoparticles in electro-oxidation of carbon monoxide and methanol.
abstract: Design of highly active nanoscale catalysts for electro-oxidation of small organic molecules is of great importance to the development of efficient fuel cells. Increasing steps on single-crystal Pt surfaces is shown to enhance the activity of CO and methanol electro-oxidation up to several orders of magnitude. However, little is known about the surface atomic structure of nanoparticles with sizes of practical relevance, which limits the application of fundamental understanding in the reaction mechanisms established on single-crystal surfaces to the development of active, nanoscale catalysts. In this study, we reveal the surface atomic structure of Pt nanoparticles supported on multiwall carbon nanotubes, from which the amount of high-index surface facets on Pt nanoparticles is quantified. Correlating the surface steps on Pt nanoparticles with the electrochemical activity and stability clearly shows the significant role of surface steps in enhancing intrinsic activity for CO and methanol electro-oxidation. Here, we show that increasing surface steps on Pt nanoparticles of approximately 2 nm can lead to enhanced intrinsic activity up to approximately 200% (current normalized to Pt surface area) for electro-oxidation of methanol.
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Lee
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.forename: Wenchao
authors.initials: W
authors.lastname: Sheng
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yabuuchi
authors.forename: Yong-Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: Tadaoki
authors.initials: T
authors.lastname: Mitani
authors.forename: Elio
authors.initials: E
authors.lastname: Vescovo
authors.forename: Yang
authors.initials: Y
authors.lastname: Shao-Horn