Work

Effect of pH during ion exchange on catalyst properties and high-temperature methane oxidation over Fe-BEA zeolites

Year: 2026

Type: article

Abstract: Methane slip from natural gas-fueled systems remains an important environmental challenge due to the high global warming potential of methane. Catalytic oxidation is therefore critical for mitigating methane slip, but affordable, efficient, and stable catalysts remain a key challenge. Among transition-metal-based catalysts, Fe-containing zeolites are promising materials as they can stabilize a wide range of Fe species with distinct structural and redox properties. However, the influence of Fe speciation on high-temperature methane oxidation activity and selectivity remains insufficiently understood. In this work, the influence of pH during liquid ion exchange of Fe-containing BEA zeolites on the catalyst composition was investigated. Increasing the pH yielded higher Fe contents, while decreasing the degree of dealumination during ion exchange. The catalysts were characterized using structural and spectroscopic techniques to establish relationships between Fe loading, Fe speciation, accessibility, redox behavior, and catalytic performance. The results show that increasing Fe contents promote the formation of oligomeric Fe x O y species and Fe 2 O 3 nanoparticles in addition to isolated framework-associated Fe species. Catalytic evaluation of high-temperature methane oxidation revealed that Fe incorporation significantly improves the activity compared to the parent zeolite. The highest CH 4 consumption rate per total mole of Fe was correlated with high proportions of dispersed Fe species, suggesting that these species contribute most effectively to methane activation. In contrast, the catalyst containing a distinct α-Fe 2 O 3 phase exhibited a significantly higher CO 2 selectivity. Overall, these findings indicate a correlation between the loading-dependent Fe speciation and catalytic activity and selectivity of Fe-BEA catalysts during high-temperature methane oxidation.

Source: Applied Catalysis O Open

DOI: 10.1016/j.apcato.2026.207124

Authors: Anne Niederdränk, Merle Blum, Jonas Kiefel, Melike Mechmed, Olaf Hinrichsen

Institution: Technical University of Munich

Language: English

Topic: Catalytic Processes in Materials Science

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,140

Funders: Bundesministerium für Wirtschaft und Energie, Graduate School, Technische Universität München