(Invited) In Situ Atomic Force Microscopy and X-Ray Spectroscopy of Electrocatalysts

Abstract

In situ characterization offers an effective way to study and quantify chemical, structural and morphological changes of electrocatalysts as well as to capture the kinetics of transformations and dissolution. For fundamental understanding of electrochemically induced transformations, such in situ experiments require well-defined materials (ideally single crystalline) as they can provide precise potential-dependent quantities that can be used to accurately assess theoretical models and predictions. In this regard, the study of materials under water oxidizing conditions represents a particular challenge due to multiple pathways for the degradation of the surface and bulk and complexity of high-quality material preparation.In this talk, I will discuss how a combination of in situ microscopy techniques can provide insight into the surface and bulk behavior of electrocatalysts during electrocatalytic water oxidation (OER). Specifically, I will show how operando electrochemical atomic force microscopy (EC-AFM) can be used to record nanoscale changes in the surface morphology during anodic corrosion of a perovskite surface. I will also discuss how operando EC-AFM can be combined with operando transmission X-ray microscopy and scanning electrochemical cell technique to probe the evolution and reactivity of single particles of Co(OH)2. In the end, I will cover key bulk and surface processes that occur in oxides under oxidative conditions as well as possible future development of in situ techniques that can help us probe such transformations.