CAREER: Iron Complexes for Hydrogen Generation and Oxygen Reduction

College Of William And Mary, Williamsburg VA

Investigators

Abstract

SusChEM: CAREER: Iron Complexes for Hydrogen Generation and Oxygen Reduction The development of clean and sustainable energy is one of the most pressing issues facing modern society. Solar energy is the most abundant form of renewable energy on earth, but is limited by a discontinuous supply. It is therefore critical to develop a way to harness and store solar energy as an energy dense chemical fuel that is compatible with our current infrastructure. Through a process called artificial photosynthesis (AP), sunlight is harnessed and used to split water into oxygen and hydrogen gas. Hydrogen gas is used directly as a fuel, or is combined with oxygen in a hydrogen fuel cell to generate electricity. Owing to expensive materials and inefficient catalysts, hydrogen generation through AP is significantly more expensive than hydrogen generated from fossil fuels. The use of hydrogen fuel cells to convert solar fuels into electricity is also limited by the use of expensive materials (platinum). In this project, Dr. William R. McNamara devises a photocatalytic system for hydrogen generation using cost-effective iron catalysts. The use of inexpensive iron catalysts for the efficient reduction of oxygen gas in hydrogen fuel cells is also investigated. Within this project, several outreach activities promote the development of future generations of scientists. Dr. McNamara is conducting an after-school program at a local public high school with a high concentration of underrepresented groups in science, technology, engineering, and mathematics (STEM). Through this program students actively conduct research in a meaningful and accessible way. These activities advance public scientific literacy while encouraging underrepresented groups to pursue careers in STEM disciplines. Funding from the Chemical Catalysis Program of the National Science Foundation supports the effort of Dr. William R. McNamara at the College of William and Mary towards the development of inexpensive materials for both photocatalytic hydrogen generation and the oxygen reduction reaction of hydrogen fuel cells. The immobilization of robust iron polypyridyl hydrogen generation catalysts on charge-separating supports (carbon nanotubes, TiO2 and SrTiO3) is characterized using attenuated total reflection infrared spectroscopy (ATR-IR) and diffuse reflectance UV-Vis spectroscopy. Hydrogen generation is promoted using an LED photolysis system and analyzed with gas chromatography. In order to decrease cost and improve the widespread applicability of photocatalytic hydrogen generation, the use of naturally occurring humic substances to replace traditional sacrificial donors is also investigated. Additionally, iron polypyridyl sulfinate catalysts are examined for the oxygen reduction reaction in hydrogen fuel cells. Rotating ring disk voltammetry (RRDV) and cyclic voltammetry (CV) are used to evaluate catalytic performance. Rigorous treatment of the data using foot-of-the-wave analysis (FOWA) is also employed to better understand mechanism. Funding from the NSF provides for the training of 15 different students (primarily undergraduates) in this multi-disciplinary research effort. Additionally, Dr. McNamara conducts an after-school research program at a local public high school with a high concentration of underrepresented groups in science. Consistent with the broader impacts of this project, these activities promote the engagement of underrepresented groups in STEM disciplines and increase public engagement in the sciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.