A Supramolecular View on the Cooperative Role of Bronsted and Lewis Acid Sites in Zeolites for Methanol Conversion.

ABSTRACT: A systematic molecular level and spectroscopic investigation is presented to show the cooperative role of Brønsted acid and Lewis acid sites in zeolites for the conversion of methanol. Extra-framework alkaline-earth metal containing species and aluminum species decrease the number of Brønsted acid sites, as protonated metal clusters are formed. A combined experimental and theoretical effort shows that postsynthetically modified ZSM-5 zeolites, by incorporation of extra-framework alkaline-earth metals or by demetalation with dealuminating agents, contain both mononuclear [MOH]⁺ and double protonated binuclear metal clusters [M(μ-OH)₂M]²⁺ (M = Mg, Ca, Sr, Ba, and HOAl). The metal in the extra-framework clusters has a Lewis acid character, which is confirmed e

SUBMITTER: Bailleul S 

PROVIDER: S-EPMC6753656 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature