Application of HCl treatment to tailor the Ga species and propane aromatization performance of various Ga incorporated MFI catalysts

• Published in: Journal of catalysis 2023-06, Vol.422, p.24-35
• Main Authors: Lim, Yong Hyun, Kim, Hyungjoo, Lee, Hwangho, Nam, Kihun, Ryu, Hae Won, Kim, Do Heui
• Format: Article
• Language: English
• Subjects: Gallium ZSM-5; Galloaluminosilicate; HCl treatment; Metal-zeolite interaction; Propane aromatization
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2023.04.003

[Display omitted] •HCl treatment was applied to Ga-based MFI samples that possess distinct Ga species.•The extent of Ga removal was based on the strength of Ga-zeolite interaction.•Appropriate removal of Ga led to an increase in propane aromatization performance.•HCl treatment following hydrothermal synthesis reliably yielded superior catalysts. The identification of various Ga species in Ga-zeolites plays a crucial role in the development of appropriate catalysts because catalytic performance depends significantly on the state of Ga. This proves to be challenging, however, because of the limited pool of conventional characterization techniques, and the diversity of chemically possible Ga conformations. Here, through investigation on three characteristic Ga-zeolites with distinct states of Ga, we demonstrate that qualitative information on the nature of Ga in these catalysts could be derived by a facile HCl treatment, based on the ability of HCl to preferably eliminate the Ga species that share weaker interaction with the zeolite. Furthermore, the treatment was able to successfully tailor the Ga species in certain Ga-zeolites by selectively retaining the most desirable species for propane activation, leading to a considerable enhancement in propane aromatization performance.