CAREER: Iron Complexes for Hydrogen Generation and Oxygen Reduction

职业：用于制氢和氧还原的铁配合物清洁和可持续能源的发展是现代社会面临的最紧迫问题之一。太阳能是地球上最丰富的可再生能源，但由于供应不连续而受到限制。因此，开发一种方法来利用和储存太阳能作为一种能量密集的化学燃料，与我们现有的基础设施兼容是至关重要的。通过一种称为人工光合作用（AP）的过程，利用阳光将水分解成氧气和氢气。氢气直接用作燃料，或者在氢燃料电池中与氧气结合发电。由于昂贵的材料和低效的催化剂，通过AP制氢比化石燃料制氢要昂贵得多。使用氢燃料电池将太阳能燃料转化为电能也受到使用昂贵材料（铂）的限制。在这个项目中，William R. McNamara博士设计了一种光催化系统，使用成本效益高的铁催化剂产生氢。还研究了在氢燃料电池中使用廉价的铁催化剂高效还原氧气的方法。在这个项目中，几项外展活动促进了未来几代科学家的发展。麦克纳马拉博士正在当地一所公立高中开展一项课后计划，该高中的科学、技术、工程和数学（STEM）领域的弱势群体高度集中。通过这个项目，学生们以一种有意义的、容易理解的方式积极地进行研究。这些活动提高了公众的科学素养，同时鼓励代表性不足的群体从事STEM学科的职业。美国国家科学基金会化学催化项目的资金支持William R. McNamara博士在William and Mary学院的努力，以开发用于光催化制氢和氢燃料电池的氧还原反应的廉价材料。利用衰减全反射红外光谱（ATR-IR）和漫反射紫外-可见光谱（UV-Vis）对负载分离载体（碳纳米管、TiO2和SrTiO3）上坚固的聚吡啶铁制氢催化剂的固定化进行了表征。利用LED光解系统促进氢的生成，并用气相色谱法进行分析。为了降低成本和提高光催化制氢的广泛适用性，还研究了使用天然腐植质物质代替传统的牺牲供体。此外，还研究了聚吡啶亚硫酸铁催化剂在氢燃料电池中的氧还原反应。用旋转环盘伏安法（RRDV）和循环伏安法（CV）评价催化性能。采用波脚分析（FOWA）对数据进行严格处理，以更好地了解机制。美国国家科学基金会资助了15名不同的学生（主要是本科生）进行这项多学科研究。此外，麦克纳马拉博士还在当地一所公立高中开展了一项课后研究计划，该高中的科学群体高度集中。与该项目的广泛影响相一致，这些活动促进了代表性不足的群体参与STEM学科，并增加了公众对科学的参与。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

SusChEM: CAREER: Iron Complexes for Hydrogen Generation and Oxygen ReductionThe 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.