Covalent Attachment of Ferrocene to Silicon Microwire Arrays

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• 作者：Onkar S. Kang ; Jared P. Bruce ; David E. Herbert ; Michael S. Freund
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：7
• 期：48
• 页码：26959-26967
• 全文大小：423K
• ISSN：1944-8252

文摘

A fully integrated, freestanding device for photoelectrochemical fuel generation will likely require covalent attachment of catalysts to the surface of the photoelectrodes. Ferrocene has been utilized in the past as a model system for molecular catalyst integration on planar silicon; however, the surface structure of high-aspect ratio silicon microwires envisioned for a potential device presents potential challenges with respect to stability, characterization, and mass transport. Attachment of vinylferrocene to Cl-terminated surfaces of silicon microwires was performed thermally. By varying the reaction time, solutions of vinylferrocene in di-n-butyl ether were employed to control the extent of functionalization. X-ray photoelectron spectroscopy (XPS) and electrochemistry were used to estimate the density and surface coverage of the silicon microwire arrays with ferrocenyl groups, which could be controllably varied from 1.23 脳 10<sup>鈥?1sup> to 4.60 脳 10<sup>鈥?0sup> mol cm<sup>鈥?sup> or 1 to 30% of a monolayer. Subsequent backfill of the remaining Si鈥揅l sites with methyl groups produced ferrocenyl-terminated surfaces that showed unchanged cyclic volammograms following two months in air, under ambient conditions, and repeated electrochemical cycling.