Photocatalytic Water Oxidation with Nonsensitized IrO2 Nanocrystals under Visible and UV Light

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• 作者：F. Andrew Frame ; Troy K. Townsend ; Rachel L. Chamousis ; Erwin M. Sabio ; Th. Dittrich ; Nigel D. Browning ; Frank E. Osterloh
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：May 18, 2011
• 年：2011
• 卷：133
• 期：19
• 页码：7264-7267
• 全文大小：748K
• 年卷期：v.133,no.19(May 18, 2011)
• ISSN：1520-5126

文摘

Rutile IrO₂ is known as being among the best electrocatalysts for water oxidation. Here we report on the unexpected photocatalytic water oxidation activity of 1.98 nm 卤 0.11 nm succinic acid-stabilized IrO₂ nanocrystals. From aqueous persulfate and silver nitrate solution the nonsensitized particles evolve oxygen with initial rates up to 0.96 渭mol min^鈥?, and with a quantum efficiency of at least 0.19% (measured at 530 nm). The catalytic process is driven by visible excitations from the Ir-d(t_2g) to the Ir-d(e_g) band (1.5鈥?.75 eV) and by ultraviolet excitations from the O-p band to the Ir-d(e_g) (>3.0 eV) band. The formation of the photogenerated charge carriers can be directly observed with surface photovoltage spectroscopy. The results shed new light on the role of IrO₂ in dye- and semiconductor-sensitized water splitting systems.