Graduation Semester and Year
2019
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Chemistry
Department
Chemistry and Biochemistry
First Advisor
Krishnan Rajeshwar
Second Advisor
Robin Macaluso
Third Advisor
Daniel W Armstrong
Fourth Advisor
Peter Kroll
Abstract
Photoelectrochemical (PEC) water splitting using inorganic semiconductors is a promising approach to convert sunlight into sustainable fuels. However, many scientific and engineering challenges need to be overcome before its commercialization. Oxide semiconductors offer many advantages such as stability in a variety of electrolytes, a diverse range of bandgaps and their Earth-abundance in nature. In this respect, many binary metal oxides have been investigated thoroughly; however, unfortunately, a suitable candidate for PEC water splitting has not been identified. While many efforts are ongoing to overcome the limitations of binary metal oxides, it is also essential to expand the search to more complex oxide families such as ternary, quaternary as well as to their composites. Nevertheless, this warrants a time-efficient route of synthesis to study such a large number of possible combinations (8,000 ternary and 700,000 quaternary oxides). Herein, we studied several complex oxides in the Cu-Bi-V-O system using a rapid- and energy-efficient solution combustion synthesis (SCS). We demonstrated the synthesis of binary CuO and α-Bi2O3 as well as their ternary combination, CuBi2O4. In addition, we prepared several composites of CuBi2O4 with binary CuO and α-Bi2O3. We systematically studied the optical and PEC behavior of these oxides and found improved photoactivities by the composites than their parent oxides which are attributed to the vectorial transfer of photogenerated carriers in them. Similarly, we developed a complexation-assisted solution combustion synthesis for multiple ternary copper vanadates. Four copper vanadates, namely α-CuV2O6, α/β-Cu2V2O7 and γ-Cu3V2O8, were prepared in “one-pot” by simply tuning the Cu/V mole ratio in the precursor solutions. This enabled comparative PEC performance assessment of these vanadates toward water splitting. The α-CuV2O6 polymorph outperformed the other three copper vanadates in PEC water splitting. This performance enhancement was attributed to its unique crystal structure and direct nature of the optical transition from the valence to the conduction band.
Keywords
Solar energy, Photoelectrochemical, Water splitting, Oxide semiconductors
Disciplines
Chemistry | Physical Sciences and Mathematics
License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.
Recommended Citation
Hossain, Mohammad Kabir, "COPPER-BASED TERNARY OXIDE SEMICONDUCTORS FOR SOLAR ENERGY CONVERSION AND ENVIRONMENTAL REMEDIATION" (2019). Chemistry & Biochemistry Dissertations. 180.
https://mavmatrix.uta.edu/chemistry_dissertations/180
Comments
Degree granted by The University of Texas at Arlington