The Structure and Reactivity of Solid-Liquid Interfaces

ABSTRACT

Characterizing and controlling solid-liquid interfaces is uniquely challenging given their buried nature yet is critical to improving the performance of electrochemical devices. In this talk, I’ll discuss our efforts to understand how electrolyte pH, dynamic solvent structures, and surface oxidation states shape both the molecular structure and reactivity of electrode surfaces. First, I’ll discuss how pH can tune the reversibility of oxygen evolution and reduction on MnO₂. I’ll show how this phenomenon arises from pH-dependent electrode charging and interactions between adsorbed catalytic intermediates and the interfacial electric field. Then, I’ll discuss how surface-sensitive Infrared Nanospectroscopy (nano-FTIR) can be used to probe electrolyte ions and water molecules inside electrical double layers at nanometer length scales. At the surface of Cu in bicarbonate electrolyte, we observe a 15 times higher ion concentration than in the bulk electrolyte, along with distinct water hydrogen bonding networks that are sensitive to the electrode surface chemistry. Lastly, I’ll present our development of operando total electron-yield scanning transmission X-ray microscopy (TEY-STXM), a new interface-sensitive X-ray spectromicroscopy technique at the Advanced Light Source. This technique enables simultaneous imaging and spectroscopy of buried interfaces with ~3 nm surface sensitivity and ~50 nm spatial resolution. I’ll show how we can resolve chemical heterogeneity at the surface of battery electrodes, measure the oxidation state of electrocatalytic active sites, and map interfacial solvent structures across electrodes.

BIO

Evan Carlson completed his PhD in William Chueh's group in the Dept. of Materials Science & Engineering at Stanford University in January, 2026. He graduated with a Bachelor’s degree in Materials Science from Stanford in 2019. His work combines electrochemistry, operando X-ray spectromicroscopy and ab-initio modeling to study solid-liquid interfaces, with an emphasis on first-row transition metal oxides. In addition to the Chueh group, he works at the SUNCAT Center for Interface Science and Catalysis (SLAC National Accelerator Laboratory) on DFT/AIMD modeling of interfacial phenomena, and as a Doctoral Fellow at the Advanced Light Source (Lawrence Berkeley National Lab), where he leads the development of new liquid-cell X-ray spectromicroscopy techniques. In his free time, he’s an avid hiker and loves exploring new cities, cuisines, and cultures.