Dr. Mahendra K. Sunkara
Department of Chemical Engineering
University of Louisville
Louisville, KY 40292
Phone: 502-852-1558
E-mail: mahendra@louisville.edu
The photocatalytic production of hydrogen via water splitting is a subject of huge interest due to its possible application for converting and storing the abundant sunlight energy as chemical energy. However with currently used materials, efficiencies of this process have been less than 1%. There is a need to develop new semiconductors with appropriate band gap for solar light absorption, band edge energetic for water splitting and chemical stability against corrosion under photolysis.
In this project, we are working on several different strategies for designing novel nanowire based materials that could potentially be stable against photocorrosion and can efficiently harvest solar light for water splitting. These strategies include: (a) band gap modification of oxide semiconductors to harvest visible part of solar spectrum; (b) protective coatings for existing visible light absorbers against photocorrosion based on the band edge engineering concepts, (c) compositional control of ternary alloys for tuning their band gap. In order to further optimize the device performance, various nanowire architecture such as 1-D arrays, and 3-D “tree-like” network are being explored for efficient separation and transport of photogenerated charges carriers.
The newly established energy conversion research facility within the Institute for Advanced Materials and Renewable Energy (IAM-RE) at UofL has all the necessary techniques for both electrochemical and photoelectrochemical characterization of the developed materials. These facilities include the necessary solar light sources, UV-Vis-NIR spectroscopy, electrochemical instrumentation, oxygen-free glove box for Li battery testing, and several instruments for electrode fabrication. The electrode materials will routinely be tested using techniques such as Mott-Schottky analysis, absorption spectroscopy, and transient photocurrent measurements. In addition, techniques such as Kelvin Probe, UV Photoelectron Spectroscopy (UPS) and PL Spectroscopy are used to determine the properties such as work function and bandgap. The proposed femto-second transient absorption spectroscopy facility (H. Rypkema) will be used to understand the fundamental behavior within the PEC cells using our new electrode materials.
mehanna@engr.uky.edu