A Sensitized Nb2O5 Photoanode for Hydrogen Production in a Dye-Sensitized Photoelectrosynthesis Cell
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- 作者：Hanlin Luo ; Wenjing Song ; Paul G. Hoertz ; Kenneth Hanson ; Rudresh Ghosh ; Sylvie Rangan ; M. Kyle Brennaman ; Javier J. Concepcion ; Robert A. Binstead ; Robert Allen Bartynski ; Rene Lopez ; Thomas J. Meyer
- 刊名：Chemistry of Materials
- 出版年：2013
- 出版时间：January 22, 2013
- 年：2013
- 卷：25
- 期：2
- 页码：122-131
- 全文大小：620K
- 年卷期：v.25,no.2(January 22, 2013)
- ISSN：1520-5002
文摘
Orthorhombic Nb2O5 nanocrystalline films functionalized with [Ru(bpy)2(4,4鈥?(PO3H2)2bpy)]2+ were used as the photoanode in dye-sensitized photoelectrosynthesis cells (DSPEC) for hydrogen generation. A set of experiments to establish key properties鈥攃onduction band, trap state distribution, interfacial electron transfer dynamics, and DSPEC efficiency鈥攚ere undertaken to develop a general protocol for future semiconductor evaluation and for comparison with other wide-band-gap semiconductors. We have found that, for a T-phase orthorhombic Nb2O5 nanocrystalline film, the conduction band potential is slightly positive (<0.1 eV), relative to that for anatase TiO2. Anatase TiO2 has a wide distribution of trap states including deep trap and band-tail trap states. Orthorhombic Nb2O5 is dominated by shallow band-tail trap states. Trap state distributions, conduction band energies, and interfacial barriers appear to contribute to a slower back electron transfer rate, lower injection yield on the nanosecond time scale, and a lower open-circuit voltage (Voc) for orthorhombic Nb2O5, compared to anatase TiO2. In an operating DSPEC, with the ethylenediaminetetraacetic tetra-anion (EDTA4鈥?/sup>) added as a reductive scavenger, H2 quantum yield and photostability measurements show that Nb2O5 is comparable, but not superior, to TiO2.