Kinetics of Anion Exchange in Nanodimensional Layered Metal Hydroxides

Marquette University, Milwaukee WI

Investigators

Abstract

In this project supported by the Experimental Physical Chemistry Program of the Chemistry Division, Prof. J.M. Hossenlopp of Marquette University will investigate the anion exchange kinetics of layered metal hydroxides that are comprised of metal hydroxide layers with replaceable anions in the nanodimensional inter-layer galleries. The versatility of these materials enables chemists to easily alter the physical and chemical properties via changes in the identity and relative stoichiometry of the metals in the hydroxide layer and/or the identity of the interlayer anions, thus making them useful for many applications. The primary goal of this project is to develop a comprehensive view of the fundamental anion exchange reactions of hydroxy double salts, HDSs, and other closely related compounds. The effects of anion size, shape, and chemical functionality will be explored in reactions of HDSs with different metal ion compositions. The temperature-dependence of the anion exchange kinetics will be determined and model-free and model-based approaches will be implemented for analysis of the data, providing a rigorous approach for characterizing the kinetics. In addition, spectroscopic methods will be developed for in-situ studies of these reactions. The data obtained in these experiments will provide a systematic framework for identifying the key features in anion exchange reactions of HDSs and other structurally-similar materials. These structural modifications are also critical for the broader impact exploiting the potential of these materials for applications of societal impact. The fundamental insight obtained here will be used to inform future development of these materials for use in polymer fire retardant additive formulations and in chemical sensor development for detecting aqueous anions of interest in environmental monitoring. In these applications, the ability to tune chemical and physical properties is critical. The research program will also support a broad range of educational activities including the training of graduate and undergraduate research students in nanomaterials science and development of undergraduate laboratory curricular materials for use at Marquette. In addition, the project will include the development of hands-on experiences in making and characterizing nanomaterials for high school students from underrepresented groups and/or economically disadvantaged backgrounds in order to encourage careers in science