Degree

Doctor of Philosophy (PhD)

Department

Cain Department of Chemical Engineering

Document Type

Dissertation

Abstract

Unsustainable exploitation of fossil fuel and its massive greenhouse gas emission necessitates the development in alternative energy sources. Chemical fuels (CH3OH or C2H5OH) outperform other choices, such as batteries for their high energy densities, which is key to portability. Electrochemical reduction of CO2is capable of producing a wide range of valuable fuels (Syngas, formic acid, methane and methanol, etc.). Converting CO2into carbon-based fuels further closes the carbon neutral cycle, which contributes to the effort in reducing global CO2emission. Integration of organic ligands with transition metals shows great potential in developing selectiveelectrochemical CO2reduction catalyst. Thiols covalently bonding to Au exhibits moeity-dependent catalysis characteristics: 6-fold enhancement in yield with 2-fold increase in selectivity for CO evolution accompanied by the suppression in the competing hydrogen evolution reaction (HER) through ligand induced surface reconstruction to specific sites; 20% increase in selectivity and 3-fold in yield for energy-dense liquid product (HCOOH) were achieved through ligand facilitated proton-coupled electron transfer by leveraging the dissociation constant (pKa) of the ligand functional moiety. Based on the insights on ligated Au electrodes, composite catalyst that integrated proton donating ligand on silica substrate with the strong CO binding Pd nanoparticle was fabricated and showed up to 6-fold selectivity and 2-fold yield increase in CH3OH production.

Date

9-11-2018

Committee Chair

Flake, John C.

DOI

10.31390/gradschool_dissertations.4712

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