Electron Transfer Mediator Effects in the Oxidative Activation of a Ruthenium Dicarboxylate Water Oxidation Catalyst

详细信息    查看全文

• 作者：Matthew V. Sheridan ; Benjamin D. Sherman ; Zhen Fang ; Kyung-Ryang Wee ; Michael K. Coggins ; Thomas J. Meyer
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：July 2, 2015
• 年：2015
• 卷：5
• 期：7
• 页码：4404-4409
• 全文大小：419K
• ISSN：2155-5435

文摘

The mechanism of electrocatalytic water oxidation by the water oxidation catalyst, ruthenium 2,2鈥?bipyridine-6,6鈥?dicarboxylate (bda) bis-isoquinoline (isoq), [Ru(bda)(isoq)₂], 1, at metal oxide electrodes has been investigated. At indium-doped tin oxide (ITO), diminished catalytic currents and increased overpotentials are observed compared to glassy carbon (GC). At pH 7.2 in 0.5 M NaClO₄, catalytic activity is enhanced by the addition of [Ru(bpy)₃]²⁺ (bpy = bipyridine) as a redox mediator. Enhanced catalytic rates are also observed at ITO electrodes derivatized with the surface-bound phosphonic acid derivative [Ru(4,4鈥?(PO₃H₂)₂bpy)(bpy)₂]²⁺, RuP²⁺. Controlled potential electrolysis with measurement of O₂ at ITO with and without surface-bound RuP²⁺ confirm that water oxidation catalysis occurs. Remarkable rate enhancements are observed with added acetate and phosphate, consistent with an important mechanistic role for atom-proton transfer (APT) in the rate-limiting step as described previously at GC electrodes.