Impact of Structural Defects and Hydronium Ion Concentration on the Stability of Zeolite BEA in Aqueous Phase

Journal Article · Wed Dec 05 00:00:00 EST 2018 · Applied Catalysis B: Environmental

DOI:https://doi.org/10.1016/j.apcatb.2018.06.065· OSTI ID:1558378

Prodinger, Sebastian  ^[1]; Shi, Hui ^[2]; Wang, Huamin ^[1]; Derewinski, Miroslaw A. ^[1]; Lercher, Johannes A.  ^[1]

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1. BATTELLE (PACIFIC NW LAB)
2. Technische Universitat Munchen

The presence of fluoride anions in the synthesis gel leads to zeolite BEA with high hydrothermal stability. This longer lifetime is caused by a lower concentration of internal silanol defects that are sites of the initial framework hydrolysis eventually destroying the lattice structure. The lifetime of these zeolites was the higher the lower the concentration of framework bridging hydroxyl groups that form hydronium ions was. While lattice hydrolysis was initiated at defect sites in all cases, the role of defects became less important as the concentration of hydronium ions increased. At higher concentration of hydrated hydronium ions, the presence of water associated with the hydrated hydronium ions limits the useful lifetime of zeolite catalysts in water. For such materials, the selective hydrophobization of the external surface extends the lifetime. Acknowledgments: S.P. and M.A.D. acknowledge support by the Materials Synthesis and Simulation Across Scales (MS3 Initiative) conducted under Laboratory Directed Research & Development Program at PNNL. H.S. and H.W. were supported by the Chemical Transformation Initiative (CTI) conducted under Laboratory Directed Research & Development Program at PNNL. J.A.L. was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1558378
• Report Number(s): PNNL-SA-133584
• Journal Information: Applied Catalysis B: Environmental, Vol. 237
• Country of Publication: United States
• Language: English