Date of Award

Summer 8-2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

Committee Chair

Dr. Wujian Miao

Committee Chair Department

Chemistry and Biochemistry

Committee Member 2

Dr. J. Paige Buchanan

Committee Member 3

Dr. Song Guo

Committee Member 3 Department

Chemistry and Biochemistry

Committee Member 4

Dr. Douglas S. Masterson

Committee Member 4 Department

Chemistry and Biochemistry

Committee Member 5

Dr. Karl J. Wallace

Committee Member 5 Department

Chemistry and Biochemistry

Abstract

Direct formic acid fuel cells (DFAFCs) have been reported as a prominent source of alternative green energy and solution to imminent energy crisis for the last two decades. The challenge to commercialize DFAFCs is primarily the utilization of cost effective, high performance and durable anodic catalyst for formic acid oxidation (FAO). Consequently, this dissertation addresses the extensive electrochemical study of a number of nanomaterials towards the potential use as electrocatalysts for FAO. Morphology and elemental analyses of the prepared nanomaterials were obtained using electron microscopy techniques.

After a general introduction and overall review of this dissertation (Chapter I), studies of the influence of chloride ions as contaminant on 20 wt% Pd/C were presented in Chapter II. The correlation between FAO peak current at glassy carbon electrode (GCE) coated with 20 wt% Pd/C (commercial), and the amount of chloride ions either added or leached from the frit of Ag/AgCl (3.0 M KCl) reference electrode were established. This study provides a guideline on how to choose a suitable reference electrode in fuel cell research.

Chapter III reports the comparative study of three different carbon based support materials and the catalytic activities towards FAO using Pd-based mono and ternary composite nanocatalysts with commercial 20 wt% Pd/C (activated carbon). The nanocatalysts were synthesized using Pd2+, Ni2+ and Co2+ precursors on Vulcan XC-72, Ketjen Black EC600, and graphite nanoparticles support materials. Vulcan XC-72 supported catalysts showed the highest FAO activities, whereas Ketjen Black support showed the best performance in terms of long-term durability. All PdNiCo-ternary composites displayed superior catalytic efficiencies towards FAO.

In Chapter IV, polyhedral oligomeric silsesquioxane (POSS) molecules were utilized as template to prepare Bi nanorods and Pd nanoparticles. Specifically, Bi nanorods were studied to evaluate the so-called third-body effect mechanism of FAO.

Finally, in Chapter V, nine transition metal complexes, prepared using POSS ligand and procured, were blended individually with 20 wt% Pd/C and explored towards FAO activity and durability. These hybrid catalysts were then investigated and ranked in terms of catalytic activity and stability for FAO using electrochemical techniques. Potential composite nanomaterials were also evaluated and proposed for further study.

ORCID ID

orcid.org/0000-0002-4370-3190

Available for download on Monday, August 05, 2019

Share

COinS