2026-07-05T16:11:53Zhttps://www.radar-service.eu/oai/OAIHandler10.35097/n63tnnpyt3mmt10b2026-07-01T14:16:48Zradar4kit
10.35097/n63tnnpyt3mmt10b
Häber, T.
T.
Häber
0000-0002-9761-4556
Institut für Katalyseforschung und -technologie (IKFT), Karlsruher Institut für Technologie (KIT)
Cardenas, C.
C.
Cardenas
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Vijayaraghavan, Sreelakshmi
Sreelakshmi
Vijayaraghavan
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Ben Othman, Iadh
Iadh
Ben Othman
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Zimina, A.
A.
Zimina
0000-0002-3111-7741
Institut für Katalyseforschung und -technologie (IKFT), Karlsruher Institut für Technologie (KIT)
Maurer, Florian
Florian
Maurer
0000-0002-3307-4132
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Grunwaldt, D.
D.
Grunwaldt
0000-0003-3606-0956
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Deutschmann, O.
O.
Deutschmann
0000-0001-9211-7529
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Lott, P.
P.
Lott
0000-0001-8683-2155
Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
Performance enhancement of Pd-based selective ammonia oxidation catalysts through forced dynamic operation
Karlsruhe Institute of Technology
2026
2026
Engineering
emission control
forced dynamic operation (FDO)
palladium catalyst
selective ammonia oxidation (SCO)
spatial profiling (SpaciPro)
Open Access
Creative Commons Attribution 4.0 International
Häber, T.
0000-0002-9761-4556
Cardenas, C.
Vijayaraghavan, Sreelakshmi
Ben Othman, Iadh
Zimina, A.
0000-0002-3111-7741
Maurer, Florian
0000-0002-3307-4132
Grunwaldt, D.
0000-0003-3606-0956
Deutschmann, O.
0000-0001-9211-7529
Lott, P.
0000-0001-8683-2155
In light of the increasing relevance of alternative energy carriers, the established domain of emission control is confronted with novel challenges. Among these carriers, ammonia (NH$_3$) has emerged as particularly promising due to its high energy density and carbon-free nature. This study focuses on the selective catalytic oxidation (SCO) of NH$_3$ to elemental nitrogen (N$_2$) under lean conditions. While conventional platinum-based catalysts exhibit high activity, they suffer from poor \ch{N2} selectivity and significant formation of nitrous oxide (N$_2$O), a potent greenhouse gas. As an alternative, palladium-based catalysts are investigated due to their inherently higher selectivity toward N$_2$. Although palladium exhibits limited activity under static feed conditions, its performance is markedly enhanced under forced dynamic operation (FDO), wherein short, intermittent reducing pulses are introduced through oxygen cut-off. This operational mode not only boosts catalytic activity beyond that of platinum but also preserves palladium’s superior selectivity. \textit{Operando} time-resolved X-ray absorption spectroscopy (XAS) and \textit{ex situ} Raman spectroscopic analysis of spent catalyst samples indicates that FDO promotes the formation of metallic palladium, which exhibits higher activity compared to palladium oxide that is the predominant phase under lean conditions. \textit{Operando} XAS uncover that a finite fraction of metallic palladium is retained at the catalyst inlet, enhancing low‑temperature activity and likely contributing to improved long‑term stability as long as \qty{300}{\degreeCelsius} is not exceeded for extended periods. These findings correspond directly to axially resolved concentration profiles of gas phase species, which reveal the development of a highly active front zone during FDO, where the majority of NH$_3$ conversion occurs selectively to N$_2$. This phenomenon is observed under both dry and humid conditions, underscoring the robustness of the approach. The results suggest that FDO enables the use of significantly shorter monolithic converters for selective NH$_3$ oxidation, i.e., a reduction of length by up to 50\% in realistic humid conditions, thereby offering substantial reductions in both reactor volume and noble metal demand for practical applications.
The research data provided includes both the processed data itself and Python scripts for reproducing the figures included in the corresponding manuscript. The “Readme.md” file explains the requirements for running the Python scripts. The scripts are numbered to correspond to the figures in the manuscript.
https://publikationen.bibliothek.kit.edu/1000194098
251,3 MB
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