Kim, SJ Jung, KD Joo, OS 2024-01-21T06:14:48Z 2024-01-21T06:14:48Z 2021-09-01 2004-10 1380-2224 https://pubs.kist.re.kr/handle/201004/137213 Ga-MCM-22 with high gallium content has been synthesized with hydrothermal method and characterized by means of X-ray diffraction, SEM, TGA, Ga-71 and Si-29 MAS NMR, BET surface area, and NH3-TPD. Ga-MCM-22 was obtained as very homogeneous particles of about 5-7 mum diameters and showed very similar morphologies to its Al analogue. The Na/Ga ratio of Ga-MCM-22 was much lower than 1.0, indicating that most of the negative framework charges should be compensated by protonated template, HMI. The results from Ga-71 and Si-29 MAS NMR demonstrated that gallium was incorporated into the tetrahedral framework of Ga-MCM-22. Also, the Si-29 MASNMR spectra showed that the as-synthesized Ga-MCM-22 has a different distribution of tetrahedral Si sites from its Al analogue. After calcination, however, the distribution of tetrahedral Si sites significantly changed, due to a large degallation from the framework of Ga-MCM-22. The NH3-TPD showed that Ga-MCM-22 possesses Bronsted and Lewis acid sites. English SPRINGER ZEOLITE MCM-22 BETA-ZEOLITE GALLIUM CRYSTALLIZATION FERRISILICATE SPECTROSCOPY CATALYSTS MEDIA Synthesis and characterization of gallosilicate molecular sieve with the MCM-22 framework topology Article 10.1023/B:JOPO.0000046348.23346.dd 1 JOURNAL OF POROUS MATERIALS, v.11, no.4, pp.211 - 218 JOURNAL OF POROUS MATERIALS 11 4 211 218 scie scopus 000224802400002 2-s2.0-10044241863 Chemistry, Applied Chemistry, Physical Materials Science, Multidisciplinary Chemistry Materials Science Article ZEOLITE MCM-22 BETA-ZEOLITE GALLIUM CRYSTALLIZATION FERRISILICATE SPECTROSCOPY CATALYSTS MEDIA gallosilicate MCM-22 zeolite substitution MAS NMR