Materials Science Colloquia September 2025

Unveiling Structure–Activity Relationships
in Crystalline and Amorphous Oxygen Evolution Reaction Catalysts

Abstract of the Seminar:

Green hydrogen production using water electrolysis is a critical technology for decarbonizing heavy industries (steel, aviation, chemicals, semiconductors) and achieving global climate goals. However, global implementation requires the development of inexpensive non-precious metal oxygen evolution reaction (OER) catalysts with significantly enhanced activity and durability. Emerging Fe/Co/Ni-oxide catalysts undergo complex (surface) reconstruction and activation processes under alkaline operating conditions. Their amorphous forms frequently demonstrate better catalytic performance compared to their crystalline counterparts due to increased defect site density and reactant adsorption. Yet, the fundamental structure-activity scaling relationships governing catalyst performance have primarily been derived from density functional theory (DFT) calculations based on well-defined crystalline surfaces, creating a significant knowledge gap when attempting to understand and optimize amorphous catalysts. To address this challenge, I systematically investigated CoSn(OH)6-derived catalysts in crystalline, defective, and amorphous forms, all prepared from a single precursor batch to ensure uniform metallic compositions. Using synchrotron X-ray diffraction and absorption spectroscopy measurements under realistic electrochemical working conditions, I demonstrate that crystalline and amorphous materials undergo distinctly different structural reconstruction pathways during catalyst activation. These characterizations enabled the identification of a highly active, covalent surface chemical motif responsible for enhanced OER performance. This discovery provides a crucial target, and experimental spectroscopic signal, for future catalyst surface engineering efforts. 

About the Speaker: 

Kenneth Crossley - Paul Scherrer Institut (PSI), Villigen (Switzerland)  

Kenneth Crossley previously studied physics (BA, Colorado College) and materials science/chemistry through the SERP+ Erasmus Mundus program (MS, Università di Genova/Université Paris-Saclay). He is currently a doctoral candidate at ETH Zürich focused on next generation oxygen evolution reaction electrocatalysts in the Electrocatalysis and Interfaces Group at the Paul Scherrer Institute (PSI). Outside the lab he enjoys fly fishing, rock climbing, drawing, skiing, and cycling.