Effect of Halide-Modified Model Carbon Supports on Catalyst Stability

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• 作者：Kevin N. Wood ; Svitlana Pylypenko ; Tim S. Olson ; Arrelaine A. Dameron ; Kevin O鈥橬eill ; Steven T. Christensen ; Huyen N. Dinh ; Thomas Gennett ; Ryan O鈥橦ayre
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2012
• 出版时间：December 26, 2012
• 年：2012
• 卷：4
• 期：12
• 页码：6728-6734
• 全文大小：489K
• 年卷期：v.4,no.12(December 26, 2012)
• ISSN：1944-8252

文摘

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.

Keywords:

electrocatalyst; durability; direct methanol fuel cell; nitrogen; fluorine and iodine functionalization; carbon support