Theses and Dissertations

Author

Xiaojing Sun

Issuing Body

Mississippi State University

Advisor

Wipf, David

Committee Member

Thomas MaGee, Thomas Gloria

Committee Member

Xia, Kang

Date of Degree

12-15-2007

Original embargo terms

MSU Only Indefinitely

Document Type

Graduate Thesis - Campus Access Only

Major

Chemistry

Degree Name

Master of Science

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

The tip generation/substrate collection mode (TG/SC) of scanning electrochemical microscopy (SECM) was used to study the ORR reactivity on Pt catalysts in sulfuric acid solution. The SECM reactivity image and the photographic image of different single crystalline regions of the etched Pt electrode correlated well. The electron backscatter diffraction (EBSD) image of Pt confirmed the surface single crystalline orientation. The image resolution is improved by employing smaller tip-substrate distance. The kinetics of the ORR on Pt surface was also studied at -15 - 30 C by means of the rotating disk voltammetry techniques. The calculated Tafel slopes for 0.1 m and 0.9 m HClO4 changed with decreasing temperature, indicating lower kinetics at low temperature. Peroxide is produced at potentials below 0 V vs SCE.

URI

https://hdl.handle.net/11668/16339

Comments

rotating ring-disk electrode||scanning electrochemical microscopy||oxygen reduction reaction||rotating disk electrode

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