Super-ions of sodium cations with hydrated hydroxide anions: inorganic structure-directing agents in zeolite synthesis
Karel Asselman, Nick Pellens, Sambhu Radhakrishnan, C. Vinod Chandran, Johan A. Martens, Françis Taulelle, Toon Verstraelen, Matti Hellström, Eric Breynaert, Christine E. A. Kirschhock
Abstract
In inorganic zeolite formation, a direct correspondence between liquid state species in the synthesis and the supramolecular decoration of the pores in the as-made final zeolite has never been reported. In this paper, a direct link between the sodium speciation in the synthesis mixture and the pore structure and content of the final zeolite is demonstrated in the example of hydroxysodalite. Super-ions with 4 sodium cations bound by mono- and bihydrated hydroxide are identified as structure-directing agents for the formation of this zeolite. This documentation of inorganic solution species acting as a templating agent in zeolite formation opens new horizons for zeolite synthesis by design.