Identifier

etd-10282014-171514

Degree

Doctor of Philosophy (PhD)

Department

Chemical Engineering

Document Type

Dissertation

Abstract

We have examined Cu-based catalyst materials that enable the conversion of CO2 to useful products such as fuels and chemical feedstocks by electrochemical reduction. In particular, we compared the electrocatalytic activity of supported Cu2O particles prepared using electrodeposition and wet chemical methods. The particles had cubic structure, ranging in size from 40 nm to 900 nm and consisting of low index planes. We observed significantly different product distribution on these catalysts compared to polycrystalline Cu, specifically for methane and ethylene formation. While Cu particles showed higher faradaic efficiency for methane formation compared to ethylene formation, we observed that Cu2O particles were more selective to ethylene than methane. For example, the C2H4/CH4 ratio on Cu was 0.2 while the C2H4/CH4 ratio on both electrodeposited Cu2O film and colloidal Cu2O particles was around 60. The Cu2O particles were reducible and the derived particles consisted of higher number of low-coordinated active sites than Cu which we propose are responsible for the increased ethylene selectivity. At -1.5VNHE, electrodeposited Cu2O film and colloidal Cu2O particles achieved highest average ethylene faradaic efficiency of 9.4% and 38% respectively while Cu foil only showed 1.2%. The colloidal Cu2O particles also exhibited better CO selectivity than Cu. While Cu showed 5.5% CO faradaic efficiency, colloidal Cu2O particles achieved highest average CO faradaic efficiency of 22%. Product distribution on Cu2O catalysts was primarily influenced by potential and was kinetically dynamic. Nafion mixed with Cu2O particles was shown to enhance and stabilize ethylene formation.

Date

2014

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Griffin, Gregory L.

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