Exploring the role of surface morphology in electrocatalytic interfaces

Many chemical reactions, such as the hydrogen evolution reaction, employ electrocatalysts to facilitate interactions between compounds. The chemistry that happens at the interface between the catalyst and the electrolyte is complex, and understanding these interactions is critical for maximizing efficiency.

Darby et al. used ab initio molecular dynamics simulations to study the electrified platinum-water interface, incorporating nanoscale edges and terraces to understand the impact of surface morphology.

“Surface morphology is extremely important because real electrodes are not uniform planes,” said author Clotilde S. Cucinotta. “They contain steps, edges, and other low coordination sites that can locally amplify the electric field and change how water molecules organize and screen charge.”

The authors observed differences in charge storage between terraces and step edges. The edges created a concentration of positive local potential and bound strongly to water molecules at the interface but exhibited only a weak charge-voltage relationship. In contrast, terraces demonstrated a strong voltage dependance and were the dominant contributing factor controlling capacitance at the potential of zero charge — the voltage where the net surface charge is minimal.

“For hydrogen production, this matters because catalyst loading and durability are key cost drivers, and both are ultimately controlled by the local interface under voltage,” said Cucinotta. “By showing that edges can concentrate positive potential without necessarily controlling capacitance near the potential of zero charge, our work clarifies which surface features shape local electrostatic environments and which ones drive the measurable charging response.”

In the future, the authors hope their research can guide the deliberate manufacture of nanostructures on the surface of electrocatalysts, tuning their electrical properties and enhancing their performance.

Source: “Surface morphology controls charge storage at the electrified Pt-water interface,” by Matthew T. Darby, Muhammad Saleh, Marialore Sulpizi, and Clotilde S. Cucinotta, Journal of Chemical Physics (2026). The article can be accessed at https://doi.org/10.1063/5.0304808 .

This paper is part of the Annabella Selloni Festschrift Collection, learn more here .