Abstract
Hierarchical porous system has become a prevalent method to overcome the diffusion limitation of conventional zeolites. Two types of mesopores characterized as intra-crystalline (mesopores in the zeolite pore wall) and inter-crystalline mesopores (meso-sized voids between nano-zeolite aggregates) could be formed in the synthesis of hierarchical zeolites. In an attempt to investigate the influence of mesopores structure on the physicochemical properties of hierarchical ZSM-5, specifically cobalt oxide impregnated ZSM-5 zeolite samples with intra- and inter-crystalline mesopores were synthesized through two different synthesis strategies. Analysis of the physicochemical properties of the as-modified hierarchical ZSM-5 catalysts were carried out using SEM, TEM, XPS, and H2-TPR which showed distinct features given by the two mesopores configurations. Co-oxide impregnated on ZSM-5 with inter-crystalline mesopores was dominated by Co(II) species, while Co-oxide/ZSM-5 showed a fair amount of Co(III) and Co(II). Furthermore, analysis of the catalytic activity was conducted using methane partial oxidation as a model reaction. With a variation in reaction time, various types of oxygenated products, i.e. methanol, formaldehyde, formic acid, and a small trace of carbon dioxide were observed. Catalytic results suggested that the Co-oxide/ZSM-5 material with inter-crystalline mesopores configuration is more active for the methane partial oxidation reaction compared to the Co-oxide/ZSM-5 with intracrystalline mesopores. This was confirmed by the formation of formaldehyde rather than methanol as the major product in the brief reaction time of 30 min.
Original language | English |
---|---|
Article number | 112896 |
Number of pages | 11 |
Journal | Microporous and Mesoporous Materials |
Volume | 365 |
Early online date | 18 Nov 2023 |
DOIs | |
Publication status | Published - 1 Feb 2024 |
Bibliographical note
Funding Information:This work was supported by Universitas Indonesia through Hibah Publikasi Terindeks Internasional (PUTI) Q2 Research Grant No. NKB-671/UN2.RST/HKP.05.00/2022 and Ministry of Research, Technology and Higher Education of the Republic of Indonesia through Pendidikan Magister menuju Doktor untuk Sarjana Unggul (PMDSU) Research Grant No. NKB-895/UN2.RST/HKP.05.00/2023 .
Data Availability Statement
Data availabilityData will be made available on request.
Supplementary data
Supplementary data to this article can be found online at https://doi.org/10.1016/j.micromeso.2023.112896.
Keywords
- Hierarchical ZSM-5
- Mesopores configuration
- Intra- and inter-crystalline mesopores
- Co-oxide ZSM-5
- Methane partial oxidation