Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 65: Solid-liquid interfaces: Reactions and electrochemistry II
O 65.11: Vortrag
Mittwoch, 11. März 2026, 17:30–17:45, TRE/PHYS
When Charged Intermediates Escape the Surface: Mass Transport Effects on the Electrocatalytic Selectivity of NO3 Reduction — •Hemanth S. Pillai, Karsten Reuter, and Vanessa J. Bukas — Fritz-Haber-Institut der MPG, Berlin
Electrocatalytic selectivity is often discussed at the atomic level on the basis of the active site, while ignoring effects of mesoscopic mass transport. And yet, transport can critically shape selectivity through the exchange of surface-bound intermediates between the electrode and bulk electrolyte. We recently explored this mechanism, originally coined “desorption–re-adsorption–reaction” [1], by developing a simple model that couples the surface reaction kinetics with diffusion [2]. Here, we advance and extend our approach to describe charged intermediates such as nitrite (NO2−) during the electrochemical NO3 reduction reaction. Ion transport augments a mean-field microkinetic model and is treated at varying levels of sophistication to capture different double layer characteristics. Our simulations show that both the applied potential and catalyst morphology uniquely shape NO2− selectivity within the desorption–re-adsorption–reaction mechanism. The emerging trends are in qualitative agreement with experiments, while distinctly different from those obtained for analogous charge-neutral intermediates during e.g. CO2 reduction. This comparison shows how the double layer affects selectivity due to transport and allows to gauge the level of detail that is required in corresponding reaction models.
[1] H. Wang et al., J. Phys. Chem. B 108, 19413 (2004).
[2] H.H. Heenen et al., Nature Catal. 7, 847 (2024).
Keywords: electrocatalysis; selectivity; Morphology; mass transport; microkinetic modelling