Physicochemical Interactions at Interfaces: Mass and Charge Transfer at Chemically Reacting Interfaces

Abstract

Aqueous multiphase interfaces which undergo chemical reactions are crucial interfacial regions for most of human technology and are relevant for many large-scale industrial activities. Using rationally designed surfaces to enhance aqueous physicochemical interactions at these critical interfaces provides a unique approach to alleviate limitations for many applications. From this perspective, the thesis presented here includes four distinct studies which interrogate interfaces undergoing a chemical reaction, with a focus on understanding the mass or charge transfer occurring at these interfaces to enable more effective transport during these chemical reactions. First, the impacts that microscale texture have for gas evolving electrochemical electrodes is investigated to highlight the unique design considerations that exist for gas evolving electrochemical electrodes that are distinctly different than non-gas evolving electrochemical systems. Next, the inactivation of active surfaces by adhered gas bubbles is investigated for gas evolving electrochemical systems. In many industrially relevant scenarios, the passivating effect that adhered bubbles have on a process are detrimental to its efficiency and overall function. The findings presented are contrary to the current prevailing understanding, bringing important implications for the design of these systems in the future. Next, when gas bubbles are intended to react in bulk aqueous solutions, their tendency to minimize their surface energy has interesting consequences, relevant for a host of transport, absorption, and mineralization processes. A new method for the absorption of gas bubbles in liquid absorbents is presented using carbon dioxide gas absorption by an alkaline absorbent as a model system with applications for sustainability. Finally, a study is presented looking at the transient impacts of gas depletion in the electroreduction of carbon dioxide into useful products to better inform how these systems can limit the impacts caused by poor mass transport of the reactant gas to their reacting electrodes. Taken together, these studies aim to demonstrate how fundamental interfacial engineering principles can be applied to enhance a variety of chemical processes involving multiphase aqueous reactions. As a consequence of the prevalence of these interfaces, the work has wide-ranging relevance, ranging from power generation and chemical conversion to global decarbonization.