O.V. acknowledges the support of Charles University through the project “Grant Schemes at CU” (Reg. no. CZ.02.2.69/0.0/0.0/19_073/0016935). J.Č. acknowledges the support of the Czech Science Foundation through the project ExPro (19-27551X). W.J.R. acknowledges the financial support from the National Science Centre Poland, grant number 2020/37/B/ST5/01258. M.S. acknowledges the support of the Ministry of Education, Youth and Sports of the Czech Republic through ERC_CZ project LL 2104. This work was also supported by Ministerstvo Školství, Mládeže a Tělovýchovy as ERDF/ESF project TECHSCALE (Nos. CZ.02.01.01/00/22_008/0004587). R.E.M. acknowledges the European Research Council for funding through the AdG 787073 “ADOR” programme.The morphology of zeolite crystals strongly affects their textural, catalytic, and mechanical attributes. However, controlling zeolite crystal morphology without using modifiers or structure-directing agents remains a challenging task because of our limited understanding of the relationships between zeolite crystal shape, crystallization mechanism, and composition of the starting synthesis mixture. In this study, we aimed at developing a general method for controlling the morphology of zeolites by assessing the impact of the Si/T molar ratio of the synthesis gel on the growth rate of zeolite crystals in various crystallographic directions and on the final crystal morphology of the UTL germanosilicate with a 2D system of intersecting 14- and 12-ring pores. Our results showed that flat UTL crystals progressively thicken with the Si/Ge molar ratio, demonstrating that Ge concentration controls the relative rate of crystal growth in the perpendicular direction to the pore system. The morphology of other zeolites and zeotypes with an anisotropic structure, including AFI (12R), IFR (12R), MWW (10–10R), and IWW (12–10–8R), can also be predicted based on their Si/T ratio, suggesting a systematic pattern across zeolite structures and in a wide range of zeolite framework elements. Combined, these findings introduce a facile and cost-efficient method for directly controlling crystal morphology of zeolites with anisotropic structures with a high potential for scale-up while providing further insights into the role of elemental composition in zeolite crystal growth.Peer reviewe
