The research objective of the NSF-BRIGE proposal is to investigate a novel one-dimensional axial PdFe core - Pt shell nanowires, which have advantageous crystallographic facets and tuned electronic properties, and can be used as efficient cathode catalysts for electrochemical energy conversion and storage devices. The overall goals are to acquire fundamental understanding of controlled wet-chemical synthesis of metallic nanocatalysts at the atomic and nano- scale, and gain knowledge of structure-catalytic functionality relationship of multi-metallic electrocatalytic systems. The career goal of the PI is to establish a world-class Nano Electrochemical Energy Program at Michigan Technological University (Michigan Tech) incorporating catalysis and clean energy with engineering, and integrating teaching / training / learning with research. Intellectual merits: Sustainably meeting humanity's energy needs has been identified as a primary research challenge for the next fifty years. Without Carnot limitation, electrochemical energy devices directly convert chemical energy of fuels (i.e. H2, ethanol, Zinc, etc) into electricity with high theoretical efficiency. However, the sluggish kinetics of oxygen reduction reaction (ORR) at cathode has been a long-standing scientific issue, which significantly reduces the electrochemical energy conversion efficiency. The PI's group has started a rigorous research on "accurate preparation of metallic nanostructures", and they have developed a wet-chemical approach to synthesis of 1-D PtFe/PdFe alloy nanowires with large electrochemical surface area and good durability. The working hypothesis is that PdFe core- Pt shell nanowires can 1) greatly improve ORR activity due to more active crystallographic facet Pt {111} on surface and optimized d-band center of surface Pt atoms; 2) significantly enhance durability due to less thermal-driven coalescence. To test this hypothesis, the PI proposes to conduct transformative research in the area of nanostructured catalysts for electrochemical energy. The specific research tasks of this proposal include: 1) precise synthesis and full characterization of carbon supported 1-D PdFe core- Pt shell nanowires (PdFe@Pt-NW/C) catalysts, 2) investigate electrochemical performance of PdFe@Pt-NW/C in three-compartment-cell, and 3) ORR and durability study in real electrochemical energy device. This NSF-BRIGE proposal fits well into the PI's long-term research interest of studying controlled synthesis of novel nanoengineered materials and understanding their electrocatalytic reaction mechanisms. Broader Impacts: The project activities will have a broad impact on research, education and outreach efforts in the Great Lakes Region through Michigan Tech's established infrastructure. The knowledge and technology generated from the research activities will advance accurate synthesis of novel catalysts at the atomic and nano- scale, and deepen understanding of structure-catalytic functionality relationship (specifically, "Pt skin-PdFe substrate interaction" with ORR activity) of multimetallic catalysts. This research effort will initiate close research collaborations with industry. It will propel development of advanced materials, deliver new discoveries, enhance Michigan Tech's infrastructure and technology-transfer, and strengthen Michigan Tech's on-going "sustainable energy" activities. This research will also help upgrade fabrication techniques of clean electrochemical energy devices. In particular, it will support the nation?s efforts to diversify its energy supply and reduce dependence on foreign oil. The proposed educational plan is to design and produce a Clean Energy Workbook. The Workbook will serve as a unique material in clean energy and catalysis education for undergraduate and secondary students. One primary audience will include diverse groups of 6th-12th grade students who participate in Michigan Tech's existing summer youth program (SYP) and diverse community college students in the existing Michigan College & University Program (MICUP), in which the majority of students are primarily drawn from traditionally underrepresented groups in science and engineering. The proposed research and education plan will help to bring more engineers from groups traditionally underrepresented (female, African American, Hispanic and Native American, disabled) into engineering areas by working on cutting-edge Nanocatalyst Technology. Exposing young students to the catalysis, clean energy, and nanotechnology research environment will inspire their curiosity and interest in science, engineering, and technology, and benefit society by sustainably supplying a number of diverse, next generation researchers that serve as role models for the scientific workforce of the future.
This BRIGE project aims to investigate novel concept one dimensional (1-D) multi-metallic electrocatalysts for oxygen reduction reaction (ORR) at cathodes for efficient electrochemical energy devices, such as fuel cells and metal air-batteries, as well as integrate the catalysis and energy research with education and outreach activities and bring more underrepresented students into engineering areas. Supported by this grant, the PI has been able to develop a universal wet-chemistry synthesis method to accurately prepare a wide range of metallic nanostructures, such as 1-D PdFe, PtFe nanowires, monometal Au, Ag, Cu, Ni, Pb, bimetal PdNi, PdAu, PdAg, etc nanoparticles with small size, narrow size distribution (2-6 nm) and controlled structures for electrochemical energy applications. 1-D Pt/Pd nanowires show higher ORR activity and better durability than conventional Pt/Pd-based catalysts in fuel cells. Formic acid electro-oxidation has been established to serve as probe reaction to monitor the restructuring of PtPd based catalysts under working conditions. The PdNi/C with a particle size of 1-6 nm and good alloy structure shows higher activity and reaction stability towards ethanol oxidation reaction than Pd/C in high pH media. The Ag/C with a particle size of 2-9 nm shows competitive ORR activity in hydrogen and glycerol anion exchange membrane fuel cells. The Au/C with a particle size of 2-6 nm demonstrates high electrocatalytic activity towards glycerol oxidation in anion exchange membrane fuel cells with cogeneration of valuable chemicals. New insights into reaction pathways of electro-oxidation of glycerol on Au/C to various valuable chemicals in high pH media have been acquired. Cu and Pb nanoparticle catalysts show potential for electrochemical reduction of CO2 or biorenewable levulinic acid to fuels or chemicals. The generated knowledge can be broadly applied to various areas, such as nanomaterials, electrochemistry, heterogeneous catalysis, green chemical processes, fuel cell, electrolysis cell, biorenewables conversion and CO2 reduction. Totally 12 peer-review papers published in high-profile journals and 20 (invited) talk and poster presentations given in AIChE, ACS, NACS, and universities have acknowledged this grant. Five Ph.D., one M.S. and five undergraduate (two female) students have been actively working on this project. They developed strong self-motivated attitude towards the clean energy research, as well as critical thinking, technical communication and leadership skills, which are critical for the success of their future academic careers. One Ph.D. graduated in 2012 and works as a postdoctoral researcher in DOE-ORNL. The PI has developed a Clean Energy workbook, serving as a unique education material to support his interdisciplinary 'Fuel Cell Fundamentals' course, undergraduate alternative fuel enterprise projects, and the Michigan Tech’s existing Summer Youth Programs (SYP). In the alternative fuel enterprise activities, 10 undergraduate students (two female and one African American) have actively participated in a fuel cell enterprise project, they not only learned catalysis, electrochemistry and alternative energy knowledge, but also developed critical thinking and high-tech development skills, as well as entrepreneurial spirits. Through SYP, over 100 diverse high school students (>40% minority) had learned catalyst preparation, electrode fabrication, fuel cell assembling and test. The comments from the high school students show that the K-12 outreach activities helped them to better understand the significance of science and engineering. The PI also established research collaborations with DOE-ORNL and DOD-NRL research groups to strengthen university's research capability and enhance training of student researchers involved in the project. This grant has facilitated the PI build up a rigorous and dynamic catalysis for clean energy research program at Michigan Tech, transformed the PI to a mature and independent researcher, and attracted traditionally underrepresented students into engineering areas.
