EAGER: Drastic Enhancement of the Electrocatalytic Activity of Metal Nanoparticles in Oxygen Reduction by Organic Capping Ligands

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Technical MeritsWith the issues surrounding fossil fuel energy, it is important to develop viable technologies for the efficient utilization of reusable and green energy sources. Fuel cells represent a powerful alternative, representing a unique technology that will make substantial contributions to our energy needs by converting the chemical energy stored in small organic molecule fuels into electricity, and more importantly, exert minimal negative impacts on the environments. Yet, despite tremendous progress in recent years, there remain several challenges in the wide-spread commercialization of fuel cells. One of these entails the development of effective catalysts for both the anodic and cathodic reactions so as to achieve the current density that is needed for practical applications.In the search for effective electrocatalysts for the oxygen reduction reaction (ORR), prior research has mostly focused on the structural characteristics of noble metal nanoparticles (e.g., size, shape, elemental composition, etc.). Professor Shaowei Chen of the University of California-Santa Cruz, believes there is an alternative catalyst type that has promise. He believes that ORR may be manipulated and optimized by the organic capping ligands for the nanoparticles, which have been largely ignored and unexplored. In fact, conventionalwisdom dictates that nanoparticle catalysts should be free of organic passivating layers. Chen?s recent studies show that the nanoparticle electrocatalytic activity may actually bedrastically enhanced by deliberate chemical functionalization with selected organic ligands,despite the fact that part of the nanoparticle surface is covered with the organic ligands. This EAGER award is to continue the exploration of this exciting new area of research, includingfurther and more detailed studies to establish a fundamental framework for the largely unknown performance impact of metal nanoparticles functionalized with metal-carbon covalent linkages.Broader ImpactsBreakthroughs in fuel cell technology are anticipated to affect many aspects of our lives and tobenefit the society as a whole. This is a relatively novel approach to prepare metal nanoparticlesstabilized by metal-carbon covalent bonds with unique aromatic derivatives and to examinetheir applications as effective and viable catalysts for the electroreduction of oxygen, a criticalprocess at fuel cell cathode. Improved performance may ultimately bring fuel cells into practical reality as energy sources. The research activities will be closely integrated with various educational outreach programs at the university (e.g., the UC LEADS, ACCESS, and SURF programs) that target minority, women, and disadvantaged undergraduate students, as well as the UCSC COSMOS summer school for talented high-school students. These research internships provide a valuable platform for the students to acquire skills that are unattainable in a conventional classroom.