Thursday, 1 September 2016

A highly active and stable iridium oxide/strontium iridium catalyst for the oxygen evolution reaction

A highly active and stable IrOx/SrIrO3 catalyst for the oxygen evolution reaction

Science  02 Sep 2016:
Vol. 353, Issue 6303, pp. 1011-1014
DOI: 10.1126/science.aaf5050

Linsey C. Seitz1, Colin F. Dickens1, 2, Kazunori Nishio3, 4, Yasuyuki Hikita3, Joseph Montoya2, Andrew Doyle2, Charlotte Kirk2, Aleksandra Vojvodic2, Harold Y. Hwang3, 4, Jens K. Norskov1, 2, Thomas F. Jaramillo1, 2, *

Author Affiliations
1SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Shriram Center, 443 Via Ortega, Stanford, CA 94305, USA.
2SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
3Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
4Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, 476 Lomita Mall, Stanford, CA 94305, USA.
*Corresponding author. Email: jaramillo@stanford.edu

Abstract

Oxygen electrochemistry plays a key role in renewable energy technologies such as fuel cells and electrolyzers, but the slow kinetics of the oxygen evolution reaction (OER) limit the performance and commercialization of such devices. Here we report an iridium oxide/strontium iridium oxide (IrOx/SrIrO3) catalyst formed during electrochemical testing by strontium leaching from surface layers of thin films of SrIrO3. This catalyst has demonstrated specific activity at 10 milliamps per square centimeter of oxide catalyst (OER current normalized to catalyst surface area), with only 270 to 290 millivolts of overpotential for 30 hours of continuous testing in acidic electrolyte. Density functional theory calculations suggest the formation of highly active surface layers during strontium leaching with IrO3 or anatase IrO2 motifs. The IrOx/SrIrO3 catalyst outperforms known IrOx and ruthenium oxide (RuOx) systems, the only other OER catalysts that have reasonable activity in acidic electrolyte.

Read more at: http://science.sciencemag.org/content/353/6303/1011?