Title

High-temperature electrocatalytic reaction mechanism at solid/gas interface based on solid-state ionic methods

Reporter

Di Chen

Reporter’s institution

The Future Laboratory, Tsinghua University

Report time

2022-4-29  10:000—12:00

Report location

Meeting Room B1301, Teaching and Research Building of Material Science(remote)

Tencent Meeting ID：521-266-406；Passcode：123456

Organizer

Hefei National Laboratory for Physical   Sciences at the Microscale，International Center   for Chemical Theory (ICCT)

Report introduction

Abstract:Electrochemical reactions on solid interfaces widely exist in various energy devices (such as fuel cells, lithium batteries, electrolysis of water for hydrogen production, etc.). In these reactions, charge and mass transport often coexist. Understanding the reaction mechanism at the atomic scale, especially determining the rate-determining steps of the reaction, plays a key role in better designing more efficient and stable interfaces at the molecular and atomic levels. In this report, I will take the oxygen reduction reaction at the oxygen/doped ceria interface as an example, and introduce a set of solid-state ionics-based, universal, micro-mechanisms of electrochemical reactions at the interface that we have established. theoretical models and experimental methods. We succeeded in separating the reaction driving forces on both sides of the interface by independently controlling the oxygen partial pressure in the gas phase and the oxygen chemical potential in the solid phase. We obtained the chemical composition and surface potential at the interface using near-atmospheric pressure XPS and XAS techniques based on synchrotron radiation. Using the established kinetic model, we connected the parameters in the Butler-Volmer equation with the microscopic mechanism of the reaction, and screened out 4 possible reaction mechanisms from 108 possible reaction mechanisms, all of which point to the participation of electrically neutral oxygen molecules speed limit steps. This method can be extended to liquid/solid interfaces represented by electrolyzed water and solid/solid interfaces represented by solid-state lithium batteries.

About the speaker:Chen Di is an associate researcher at the Future Lab of Tsinghua University. He received a bachelor's degree from the Department of Materials Science and Engineering of Tsinghua University, a Ph.D. degree from the Department of Materials Science and Engineering of MIT, worked in industry for two years, and completed postdoctoral training in the Department of Materials Science and Engineering of Stanford University. As the first author and co-author, he has published many papers in Nature Catalysis, Advanced Functional Materials, Chemistry of Materials, Nature Materials, Nature Nanotechnology and other journals. He presided over the National Key R&D Program Young Scientist Program, the National Key R&D Program Intergovernmental International Science and Technology Innovation Cooperation Program, the National Natural Science Foundation of China and other vertical and several horizontal industry-university-research projects.