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Electrical and Photoelectrochemical Characterization of Single Crystal Bismuth Vanadate


EMSL Project ID
47655

Abstract

Bismuth vanadate (BiVO4) is a promising electrode material in photoelectrochemical (PEC) cells. Recently, it has been shown that doping with Mo and W dramatically improves its performance, but the reasons behind these improvements are unclear. It is likely that these impurities are affecting the electronic properties of this material, but these have not been characterized. In fact, electrical characterization of BiVO4 has only been performed above 673K, where conduction is predominately ionic. The operating temperature range for PEC cells is 300-400K.
We have synthesized small (1-5 mm3) single crystal samples of undoped and doped BiVO4 using the floating zone technique. As BiVO4 is semiconducting, the samples are highly resistive and can only be measured on customized apparatus, such as the modified Physical Property Measurement System at PNNL. To the best of our knowledge, no other facility capable of this exists in the country. Further, accurate sample composition is essential, and will be characterized using the Rutherford backscattering spectroscopy (RBS) and proton-induced x-ray emission (PIXE) capabilities at PNNL.
This study will, for the first time, report electronic transport mechanisms and the Hall effect in BiVO4. The effects of Mo and W on carrier concentrations and mobilities will also be elucidated. A better understanding of these underlying mechanisms, only measurable using the unique capabilities at PNNL, will allow us to design better BiVO4-based photoanodes for renewable hydrogen production.

Project Details

Project type
Exploratory Research
Start Date
2012-10-18
End Date
2013-10-18
Status
Closed

Team

Principal Investigator

C. Buddie Mullins
Institution
University of Texas at Austin

Team Members

Cigdem Capan
Institution
Washington State University Tri-Cities

John McCloy
Institution
Washington State University

Related Publications

Rettie AJ, HC Lee, LG Marshall, JF Lin, C Capen, J Lindemuth, JS McCloy, J Zhou, AJ Bard, and CB Mullins. 2013. "Combined Charge Carrier Transport and Photoelectrochemical Characterization of BiVO4 Single Crystals: Intrinsic Behavior of a Complex Metal Oxide." Journal of the American Chemical Society 135:11389-11396.