title: Dissolution Kinetics of Oxidative Etching of Cubic and Icosahedral Platinum Nanoparticles Revealed by in Situ Liquid Transmission Electron Microscopy.
abstract: Dissolution due to atom-level etching is a major factor for the degradation of Pt-based electrocatalysts used in low-temperature polymer electrolyte membrane fuel cells. Selective surface etching is also used to precisely control shapes of nanoparticles. Dissolution kinetics of faceted metal nanoparticles in solution however is poorly understood despite considerable progress in understanding etching of two-dimensional surfaces. We report here the application of in situ liquid transmission electron microscopy for quantitative analysis of oxidative etching of cubic and icosahedral Pt nanoparticles. The experiment was carried out using a liquid flow cell containing aqueous HAuCl4solution. The data show that oxidative etching of these faceted nanocrystals depends on the location of atoms on the surface, which evolves with time. A quantitative kinetic model was developed to account for the mass lost in electrolyte solutions over time, showing the dissolutions followed the power law relationship for Pt nanocrystals of different shapes. Dissolution coefficients of different surface sites were obtained based on the models developed in this study.
authors.affiliation: Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , 1304 West Green Street, Urbana, Illinois 61801, United States.|Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801, United States.|Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , MC-712, 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , 1304 West Green Street, Urbana, Illinois 61801, United States.|Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801, United States.
authors.forename: Wenpei
authors.initials: W
authors.lastname: Gao
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign , MC-712, 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Hong
authors.identifier: 0000-0003-3459-4516
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , 1304 West Green Street, Urbana, Illinois 61801, United States.|Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , 104 South Goodwin Avenue, Urbana, Illinois 61801, United States.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zuo
keywords: corrosion; in situ liquid TEM; kinetics; oxidative etching; platinum