Elucidating the Effects of Structure on the Redox Reactivity of Mycogenic Mn Oxide Nanoparticles

In this project funded by the Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation, Owen Duckworth, Matthew Polizzotto, and Leslie Sombers of North Carolina State University and Cara Santelli of the Smithsonian Institution are working on a project that has significant educational and training potential. An interdisciplinary team of predominantly early-career investigators at NC State University and the Smithsonian Institution has been assembled who will collaborate with a cadre of international experts. The project will also provide research experiences for a postdoctoral fellow, a doctoral student, and several undergraduates from groups underrepresented in Science, Technology, Engineering, and Mathematics (STEM). The rich intellectual environment stimulated by interdisciplinary interactions and travel to domestic and international collaborating laboratories will endow students and postdoctoral researchers working on the project with the broad perspectives and technical skills required to solve emerging problems in environmental chemistry. Additionally, the Smithsonian Institution will provide opportunities for scientists to educate and interact with the general public through a variety of outreach engagements at the National Museum of Natural History.

The project focuses on understanding how mineral structure underlies various properties of Mn oxides produced by fungi. Manganese-oxidizing fungi isolated from a Superfund site will be used to produce Mn(IV) oxide nanoparticles doped with different metal ions, which will result in structural variability, including changes to the site of dopant metal incorporation, the number of structural defects, the Mn(III) content, and the ordering of mineral layers. The particles will be carefully characterized by a complementary array of cutting-edge spectroscopic, microscopic, voltammetric, computational, and X-ray scattering methods to determine their structure and electrical properties. Kinetics and products of redox reactions between the Mn oxide nanoparticles and a set of substituted quinones, which function as probes of redox reactivity, will be quantified to gain a holistic view of mycogenic oxide properties. Potential outcomes will be to transform our view of surface chemistry by developing new integrated conceptual models that link mineral structure, electrical properties, and reactivity, and the development of novel approaches to environmental remediation and other technologies.