Acidity characterization and adsorption characteristics of cobalt and lead doped SBA15 mesoporous materials

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Kimya Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2007

Öğrenci: ÖZGE GÜNER

Danışman: DENİZ ÜNER

Özet:

In this study, the surface acidity of Co and/or Pb doped SBA15 mesoporous catalysts were investigated by both diffuse reflectance fourier transform (DRIFT) infrared spectroscopy and transmission mode fourier transform infrared spectroscopy. Pyridine was used to identify the Brønsted and Lewis acid sites of the surface, at room temperature. From the DRIFT spectrum typical stretching vibrations of isolated terminal silanol (Si-OH) groups were observed for all the catalysts. These silanol group bands dissappeared after pyridine adsorption, indicating that these silanol groups are acidic and serve as chemical adsorption sites for pyridine. Pyridine adsorption on these catalysts revealed that while monometallic additions did not influence the overall acidity of SBA15, in the bimetallic system, characteristic bands due to pyridine adsorption on Co2+ ions were observed.