Photocatalytic Water Oxidation with Nonsensitized IrO2 Nanocrystals under Visible and UV Light
Authors:
- Troy K. TownsendTTTroy K. Townsend
- Rachel L. ChamousisRCRachel L. Chamousis
- Erwin M. SabioESErwin M. Sabio
- Nigel D. BrowningNBNigel D. Browning
- Frank E. OsterlohFOFrank E. Osterloh
- 27 April 2011
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 133 (19) , 7264-7267
Abstract
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 ± 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 μmol min–1, 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(t2g) to the Ir-d(eg) band (1.5–2.75 eV) and by ultraviolet excitations from the O-p band to the Ir-d(eg) (>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.Keywords
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