Abstract
The effects of precipitant and solid basicity on the Fischer-Tropsch Synthesis (FTS) activity of the sodium doped zinc ferrite catalysts were investigated. Olefin selectivity and stability of the catalysts were interrelated with the solid basicity which varied with the type of the precipitant, the amount of alkali promoter and its incorporation way into the catalyst matrix. The type of the precipitant and ionic medium of hydrolysis were seen to affect the textural properties of zinc ferrites. A cubic spinel phase of ZnFe2O4 were observed for all catalysts. Sodium promoter significantly modified the reduction behavior of the samples as well. Since the ionic strength was believed to have an effect on the solubility constants of Fe(OH)3 and Zn(OH)2, the purity of ZnFe2O4 nanoparticles would be expected to change as to be noticed from their different TPR profiles. All zinc ferrite samples had a much smaller crystal size than the precipitated iron, showing the structural promoter effect of zinc. In the study, the basicity of the catalysts was also correlated with FTS activity. All alkali promoted zinc ferrite catalysts have shown high olefin selectivity of about 50%. Although a basicity of certain extent is a must to attain high olefin selectivity, coking seems inevitable at high basicity. Therefore, an optimum interaction strength of the surface for CO dissociation appeared to exist and it might be tuned by surface basicity.
| Original language | English |
|---|---|
| Article number | 112866 |
| Journal | Molecular Catalysis |
| Volume | 535 |
| DOIs | |
| Publication status | Published - 15 Jan 2023 |
Bibliographical note
Publisher Copyright:© 2022 Elsevier B.V.
Funding
This study is conducted under the project “Development of Catalyst and Reactor Technology to Produce Lower Olefins from Clean Syngas” (Contract Code: 217M924). The authors greatly acknowledge to “The Scientific and Technological Research Council of Turkey (TUBITAK)” for funding the Project. This study is conducted under the project “Development of Catalyst and Reactor Technology to Produce Lower Olefins from Clean Syngas” (Contract Code: 217M924). The authors greatly acknowledge to “The Scientific and Technological Research Council of Turkey (TUBITAK)” for funding the Project. TUBITAK Marmara Research Center (TUBITAK-MAM) and Dr. Nuri Solak from Metallurgical Engineering Department of Istanbul Technical University are kindly acknowledged for their support for material characterizations.
| Funders | Funder number |
|---|---|
| TUBITAK Marmara Research Center | |
| Türkiye Bilimsel ve Teknolojik Araştırma Kurumu | |
| Istanbul Teknik Üniversitesi |
Keywords
- Co-precipitation
- Fischer-Tropsch synthesis
- Light olefin
- Na promoter
- Zinc ferrite catalyst