Unassisted Photoelectrochemical Solar-to-Hydrogen on CuBi2O4 Photocathodes Using Glycerol as a Sacrificial Oxidant
Date of Graduation
Bachelor of Science in Chemistry
Chemistry & Biochemistry
Committee Member/Second Reader
Committee Member/Third Reader
The need to decarbonize society has driven the development of alternative energy technologies. Solar panels are capable of generating electricity at large scale and at competitive costs to fossil fuels, such as coal or natural gas. However, they are only capable of generating electricity when the sun is out. It is therefore necessary to understand how to store that energy for on-demand use. It is also desirable that the storage be portable, lightweight, and compatible with transportation infrastructure like fossil fuels are. A very desirable chemical fuel is H2 which can be produced simply by water electrolysis. Production of H2 can be achieved through photoelectrochemical (PEC) water splitting. PEC allows for the undeviating conversion of sunlight to H2 and O2 without producing harmful pollutants like carbon dioxide. Devices that facilitate PEC water splitting resemble the structure of biological membranes that drive photosynthesis (Berg). They are generally composed of a photoanode (2𝐻!𝑂→𝑂!+4𝐻"+ 4𝑒#) and a photocathode (2𝑒#+2𝐻" →𝐻!) (Minggu).
Photoelectrochemical solar energy to fuels conversion is an artificial analogy to natural photosynthesis. That is, to capture energy from sunlight and store that energy is some form of chemical bond through various reactions. For any type of artificial photosynthesis, both a catalyst and light absorber are necessary for specific chemical reactions. The light absorber captures and directs excited electrons and holes from the absorption of sunlight to catalysts for the desired anode and cathode reactions Previously, the PEC cell was being used to perform water splitting in hopes to generate hydrogen. However, water splitting was replaced with the combination of hydrogen evolution glycerol oxidation (Schichtl). This replacement was made due to the significant reduction in overall cell potential required for the total cell reaction. Water splitting requires 2V to occur. However, H2+glycerol oxidation requires 0.6-0.8V to occur. This difference in voltage is desirable for hydrogen production. Thus, a light absorber is needed that operates within the voltage range of H2+glycerol oxidation. CuBi2O4 is the chosen light absorber considering it gives 0.8V (Kang).
Eddy, C. (2022). Unassisted Photoelectrochemical Solar-to-Hydrogen on CuBi2O4 Photocathodes Using Glycerol as a Sacrificial Oxidant. Chemistry & Biochemistry Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/chbcuht/37