title: Effect of halide-modified model carbon supports on catalyst stability.
abstract: Modification of physiochemical and structural properties of carbon-based materials through targeted functionalization is a useful way to improve the properties and performance of such catalyst materials. This work explores the incorporation of dopants, including nitrogen, iodine, and fluorine, into the carbon structure of highly-oriented pyrolytic graphite (HOPG) and its potential benefits on the stability of PtRu catalyst nanoparticles. Evaluation of the changes in the catalyst nanoparticle coverage and size as a function of implantation parameters reveals that carbon supports functionalized with a combination of nitrogen and fluorine provide the most beneficial interactions, resulting in suppressed particle coarsening and dissolution. Benefits of a carefully tuned support system modified with fluorine and nitrogen surpass those obtained with nitrogen (no fluorine) modification. Ion implantation of iodine into HOPG results in a consistent amount of structural damage to the carbon matrix, regardless of dose. For this modification, improvements in stability are similar to nitrogen modification; however, the benefit is only observed at higher dose conditions. This indicates that a mechanism different than the one associated with nitrogen may be responsible for the improved durability.
authors.affiliation: Department of Metallurgical & Materials Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA.
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Wood
authors.forename: Svitlana
authors.initials: S
authors.lastname: Pylypenko
authors.forename: Tim S
authors.initials: TS
authors.lastname: Olson
authors.forename: Arrelaine A
authors.initials: AA
authors.lastname: Dameron
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Neill
authors.forename: Steven T
authors.initials: ST
authors.lastname: Christensen
authors.forename: Huyen N
authors.initials: HN
authors.lastname: Dinh
authors.forename: Thomas
authors.initials: T
authors.lastname: Gennett
authors.forename: Ryan
authors.initials: R
authors.lastname: O'Hayre