Thermodynamic stability and activity volcano for perovskite-based oxide as OER catalyst

Design of efficient and cost-effective catalysts for the oxygen evolution reaction (OER) is crucial for the development of electrochemical conversion technologies. Recent experiments show that perovskite transition-metal oxides can exhibit high electro-catalytic activity for OER. Both binding strength of reaction intermediate and [sigma]*-antibonding (eg) orbital filling of transition-metal ions in the clean surface prove to be descriptors of perovksite activity. Plotting of activity vs. a descriptor gives a volcano curve. However, little is known about the thermodynamic stability and the catalytic activity of perovskite surface reconstructions. Reconstructions such as defect, adsorbate, and steps are widely detected in experiments. They are caused by realistic environment during fabrication, measurement, and eventual device operation. In this work, we apply first-principles density functional theory and ab initio electro-thermodynamics to investigate the environment-dependent surface reconstructions of perovskite, particularly those based on LaMnO 3. We develop a surface stability phase diagram as a function of pH and electrode potential, and compare those catalytic activities under realistic liquid environment of electrolysis device. Our results show that values of pH and electrode potential can greatly affect surface structure and its activity. The new approach developed in this work is applicable to other oxide catalysts.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Rong, Xi, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Alexie M. Kolpak.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/92129

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/92129