Steady-State Synthesis of Colloidal Nanocrystals under One-Shot Injection

About This Grant

With the support from the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Younan Xia of the Georgia Institute of Technology and Professor Emmanouil Mavrikakis of the University of Wisconsin-Madison will develop a knowledge base for achieving robust, reproducible, and scalable production of colloidal nanocrystals. Colloidal nanocrystals with well-controlled properties are beneficial to the U.S. economy and society. For example, the nanocrystals have potential applications as advanced catalytic materials essential to energy conversion and environmental protection, as well as production of important chemicals and pharmaceuticals. The multi-disciplinary and collaborative nature of this project will offer a natural vehicle to enrich the education and training experiences of all participants. The results from this project will be adapted to enhance classroom teaching, including the development of demonstrations (both animations and experiments) related to the key concepts of chemistry and chemical engineering. Through an integration of experimental studies and computational modeling, three methods will be developed and validated for realizing nanocrystal synthesis under both steady-state kinetics and one-shot injection. In the first method, the dissociation equilibrium of a weak acid is leveraged to maintain its conjugate base (the actual reductant) at a constant and controllable level. Due to the dissociation equilibrium, the conjugate base will remain at a fixed concentration until all the added acid is consumed. In the second method, an insoluble salt precursor is used to ensure that the metal ion (the actual precursor) in the reaction solution will stay at a constant level. The third method borrows the concept of controlled release from drug delivery by loading the precursor or reducing agent in polymer beads. Under zero-order release, the precursor or reducing agent in the reaction mixture will exist at a low and constant concentration as it will undergo immediate consumption upon release from the beads. When the other reactant is used in large excess to stay at a constant concentration, these methods will enable the establishment of steady-state kinetics. Along with experimental inquiries, computational studies will be conducted to achieve a better understanding of the dissolution, dissolution, reduction, and growth mechanisms. 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.