Synthesis of Well-Ordered Mesoporous Aluminosilicates with High Aluminum Contents: The Challenge and the Promise

• Published in: Inorganic chemistry Vol. 61; no. 30; pp. 11820 - 11829
• Main Authors: Deng, Yixiong, Zhou, Jiayu, Li, Gen, Liu, Honghai, Gao, Xionghou, Yue, Yuanyuan, Li, Haiyan, Xie, Fangming, Liu, Hongtao
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01.08.2022
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.2c01571

SBA-15 has recently emerged as a potential material for the catalytic conversion of large molecules. Usually, SBA-15 has a low content of aluminum due to the conventional acidic synthesis medium. Although a few approaches have been adopted to prepare Al–SBA-15 with a high alumina content, it is still challenging to prepare well-ordered Al–SBA-15 with a high alumina content. Here, we demonstrate a facile synthesis process in neutral mediums for the grafting of Al into the framework of SBA-15. This approach relies mainly on the dissociation of Si–O–Si bonds and the polymerization of Si–O–Si/Al bonds promoted by sodium persulfate (SPS) in neutral mediums. In this way, well-ordered Al–SBA-15 with a high aluminum content and enhanced acidity was obtained. Results of X-ray fluorescence spectroscopy (XRF) showed an n(SiO2)/n(Al2O3) ratio of 13.7, much lower than that of the conventional sample (21.7) obtained in acidic medium. The characterization results indicated the presence of a well-ordered Al-containing mesophase with high hydrothermal stability. Notably, the Al content and the acidity of Al–SBA-15 can be tuned by changing the SPS amount.