Shaping the energy landscape toward renewable energy resources is a contemporary challenge that requires significant advancements in development of catalysts for energy conversion and storage via fuel cells, electrolyzers, and metal-air batteries. Oxygen electrocatalysis plays a key role in the performance of these systems. It mainly revolves around the catalysis of oxygen evolution during water splitting in the presence of electrons storing energy in chemical form in electrolyzers, and subsequent recombination of O2 with H2 to form water in fuel cells, generating electrical energy. The sluggish, complex chemistry of oxygen in these systems leads to large overpotential losses that significantly affect the overall efficiency. Therefore, design of cost-effective catalytic materials that improve oxygen electro-kinetics could significantly contribute toward enhancing the overall efficiency of electrochemical energy conversion and storage systems. Non-stoichiometric mixed metal oxides with mixed ionic and electronic conducting properties, such as perovskites, double perovskites, and Ruddlesden-Popper oxides, present a promising group of electrocatalysts for oxygen electrocatalysis due to the versatility of their surface compositions and fast oxygen ion conducting properties. While promising development of design criteria for oxygen electrocatalysis on these oxides has been hampered by the complexity of their structure. To address this challenge, we have developed a reverse microemulsion approach to control the surface structure of these oxides such as to develop structure-performance relations that can guide the identification of nonstoichiometric, mixed ionic-electronic conducting oxides for efficient oxygen electrocatalysis. We show that surface structure plays a key role in controlling oxygen electrocatalysis. We report that oxide properties, such as surface oxygen reduction can be used to predict the activity and stability of these oxides under electrochemical conditions.

Well-defined nanostructures of nonstoichiometric, mixed metal oxides for oxygen electrocatalysis

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.