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| Title: | Fine Crystallized LDHs Prepared with SiO 2 Sphere as Highly Active Solid Base Catalyst |
| Authors: | Shirotori, Mahiro
Nishimura, Shun
Ebitani, Kohki |
| Issue Date: | 2017-03-17 |
| Publisher: | Royal Society of Chemistry |
| Magazine name: | Journal of Materials Chemistry A |
| Volume: | 5 |
| Number: | 15 |
| Start page: | 6947 |
| End page: | 6957 |
| DOI: | 10.1039/C7TA00984D |
| Abstract: | Fine-crystallized layered double hydroxides were prepared by co-precipitation method with coexistence of SiO2 sphere (SiO2@LDH), and these base catalysis and structural properties were investigated. As-prepared SiO2@LDHs exhibited higher base catalysis for the Knoevenagel condensation than conventional LDHs prepared by co-precipitation method in absence of co-existence of SiO2 sphere. Such increase in activity for base catalysis was also observed in various types of SiO2@LDHs with different metal compositions (M2+: Mg2+ or Ni2+, M3+: Al3+ or Ga3+, M2+/M3+: 1 or 3). X-ray diffraction (XRD) measurement suggested that addition of SiO2 induced the decrease in LDH crystallite size. The results of transmission electron microscopy – energy dispersive X-ray spectroscopy (TEM-EDS) and 29Si cross polarization magic angle spinning nuclear magnetic resonance (29Si CP-MAS NMR) on SiO2@Mg-Al LDH suggested that the crystal of Mg-Al LDH is immobilized on SiO2 surface through the Si-O-Al and Si-O-Mg covalent bonds. According to these results, we concluded that the co-precipitation method in the presence of colloidal spherical SiO2 seeds, especially possessing 40 nm diameter, composed the highly-dispersed points of LDH crystal growth on SiO2 surface, and which lead the generation of fine-crystallized highly active LDH nanocrystals. |
| Rights: | Copyright (C) 2017 Royal Society of Chemistry. Mahiro Shirotori, Shun Nishimura and Kohki Ebitani, Journal of Materials Chemistry A, 2017, 5(15), 6947-6957. https://doi.org/10.1039/C7TA00984D - Reproduced by permission of the Royal Society of Chemistry |
| URI: | http://hdl.handle.net/10119/19041 |
| Material Type: | author |
| Appears in Collections: | d10-1. 雑誌掲載論文 (Journal Articles)
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