Untangling Photoreactivity of Oxide Nanoparticles

Lehigh University, Bethlehem PA

Investigators

Abstract

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, Lisa Fredin of Lehigh University is exploring the photochemical and photophysical properties of titanium dioxide nanoparticles using computational methods. While surface structure is known to have a fundamental impact on the properties of photocatalysts, most current models cannot capture the complexity of real experimental systems. In particular, nanosized photocatalysts are widely used but new models that can predict the reactivity at corners and edges of these particles are needed. Dr. Fredin and her students will build systematic nanotitania models and then use them to directly explore photophysics and reactivity of this industrially important material. Their discoveries could lead to a better understanding of the chemistry and physics of nanotitania interfaces and transform how models of photocatalysts are developed. In addition, their efforts could increase diversity and computationally literacy in the STEM (science, technology, engineering and mathematics) workforce through providing immersive research experiences for early career undergraduates and students from underrepresented groups and dedicated hands-on scientific computation and coding workshops. This project focuses on computational studies of photophysics and reactivity of nanotitania particles. The proposed work will build large cluster models of nanostructured titania with both faceted and amorphous surfaces. By systematically comparing various shaped particles, the proposed research has the potential to provide a more complete understanding of how to model the photoresponse and reactivity of nanoscale oxides before running an experiment. Using density functional theory (DFT) methods and large cluster models, this work aims to provide the first systematic calculation of photocatalytic barriers on oxide facet edges and amorphous nanoparticle surfaces. This study will likely improve first principle models of photocatalysis by providing in depth insights into important materials used in a wide variety of applications and reactions. 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.