Facile Photochemical Preparation of Amorphous Iridium Oxide Films for Water Oxidation Catalysis
详细信息 查看全文
- 作者：Rodney D. L. Smith ; Barbora Sporinova ; Randal D. Fagan ; Simon Trudel ; Curtis P. Berlinguette
- 刊名：Chemistry of Materials
- 出版年：2014
- 出版时间：February 25, 2014
- 年：2014
- 卷：26
- 期：4
- 页码：1654-1659
- 全文大小：369K
- 年卷期：v.26,no.4(February 25, 2014)
- ISSN：1520-5002
文摘
Light-driven decomposition of Ir(acac)3 spin-cast on a conducting glass substrate produces a thin conformal film of amorphous iridium oxide, a-IrOx. The decomposition process, which was carried out under an ambient atmosphere at room temperature and tracked by Fourier transform infrared (FTIR) spectroscopy, appears to proceed by way of a ligand-to-metal charge transfer (LMCT) process. The amorphous nature of the films is based on the lack of any observable Bragg reflections by powder X-ray diffraction techniques; the elemental composition was corroborated by X-ray photoelectron spectroscopy (XPS) measurements. The films are found to be excellent electrocatalysts for mediating the oxygen evolution reaction (OER) in acidic media, as evidenced by the onset of catalysis at 130 mV and a Tafel slope of 34 mV decp>鈥? p>. These parameters enable current densities of 1 and 10 mA cmp>鈥? p> to be reached at 190 and 220 mV, respectively. Exposing the films to higher temperatures (500 掳C) renders a film of crystalline iridium oxide, c-IrOx, which displays a Tafel slope of 60 mV decp>鈥? p>, thus requiring an additional 50 mV to reach a current density of 1 mA cmp>鈥? p>. The film of a-IrOx reported here is among the best OER electrocatalysts reported to date.