Leaching Stability and Redox Activity of Copper-MFI Zeolites Prepared by Solid-State Transformations: Comparison with Ion-Exchanged and Impregnated Samples Full article
| Journal |
Materials
ISSN: 1996-1944 |
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| Output data | Year: 2023, Volume: 16, Number: 2, Article number : 671, Pages count : 23 DOI: 10.3390/ma16020671 | ||
| Tags | Cu-ZSM-5; copper-containing silicalite; preparation route; oxide cluster of Cu2+ cations; CuO nanoparticle | ||
| Authors |
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| Affiliations |
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Funding (1)
| 1 | Russian Science Foundation | 17-73-30032 |
Abstract:
The catalyst preparation route is well known to affect the copper loading and its electronic state, which influence the properties of the resulting catalyst. Electronic states of copper ions in copper-containing silicalites with the MFI-framework topology obtained by a solid-state transformation S (SST) were studied with using EPR, UV-Vis DR, XRD, H2-TPR and chemical differentiating dissolution. They were compared with Cu-ZSM-5 and Cu-MFI (silicalite) prepared via the ion-exchange and incipient wetness impregnation. SST route was shown to provide the formation of MFI structure and favor clustering of Cu-ions near surface and subsurface of zeolite crystals. The square-planar oxide clusters of Cu2+-ions and the finely dispersed CuO nanoparticles with the size down to 20 nm were revealed in Cu-MFI-SST samples with low (0.5–1.0 wt.%) and high (16 wt.%) Cu-content. The CuO nanoparticles were characterized by energy band gap 1–1.16 eV. The CuO-like clusters were characterized by ligand-to-metal charge transfer band (CTB L → M) at 32,000 cm−1 and contain EPR-visible surface Cu2+-ions. The low Cu-loaded SST-samples had poor redox properties and activity towards different solvents due to decoration of copper-species by silica; whereas CuO nanoparticles were easily removed from the catalyst by HCl. In the ion-exchanged samples over MFI-silicalite and ZSM-5, Cu2+-ions were mainly CuO-like clusters and isolated Cu2+ ions inside MFI channels. Their redox properties and tendency to dissolve in acidic solutions differed from the behavior of SST-series samples.
Cite:
Yashnik S.A.
, Surovtsova T.A.
, Salnikov A.V.
, Parmon V.N.
Leaching Stability and Redox Activity of Copper-MFI Zeolites Prepared by Solid-State Transformations: Comparison with Ion-Exchanged and Impregnated Samples
Materials. 2023. V.16. N2. 671 :1-23. DOI: 10.3390/ma16020671 WOS Scopus РИНЦ AN PMID OpenAlex
Leaching Stability and Redox Activity of Copper-MFI Zeolites Prepared by Solid-State Transformations: Comparison with Ion-Exchanged and Impregnated Samples
Materials. 2023. V.16. N2. 671 :1-23. DOI: 10.3390/ma16020671 WOS Scopus РИНЦ AN PMID OpenAlex
Dates:
| Submitted: | Nov 27, 2022 |
| Accepted: | Jan 3, 2023 |
| Published print: | Jan 10, 2023 |
| Published online: | Jan 10, 2023 |
Identifiers:
| Web of science: | WOS:000927571400001 |
| Scopus: | 2-s2.0-85146599228 |
| Elibrary: | 53957588 |
| Chemical Abstracts: | 2023:172518 |
| PMID: | 36676413 |
| OpenAlex: | W4315648037 |