Controlling Polymorphism in Nanoporous Aluminosilicates from First Principles

Zeolites are nanoporous aluminosilicate materials with broad applications in catalysis and separations. Over 250 polymorphs are known and thousands more are predicted to be possible. However, managing polymorphism and phase competition in zeolite synthesis typically requires intensive trial and error. This complexity arises from the interplay among experimental synthesis conditions like temperature, time or composition, and because of the role of structure-directing organics and inorganics in the reaction mixture. High-throughput computational tools, built on a combination of theoretical and data-driven approaches and validated retroactively against computer-extracted literature, can produce insights and quantitative predictions for controlling these phases.<br/><br/>In particular, we have recently proposed new computational strategies to estimate the binding affinity between molecular templates and pores that are fast and scalable. By simulating the affinity of thousands of organic templates towards all existing zeolites – and not just the desired target – it then becomes possible to estimate selectivity and not just affinity. The newly proposed affinity and selectivity metrics between zeolite and organic structure-directing agents are found to rationalize phase competition in historical data. Based on these principles and using over 1 million OSDA-zeolite simulations, we have realized novel simple and low-cost molecules the synthesize AEI and CHA zeolite materials with equal or better selectivity than state-of-the-art templates. Furthermore, it becomes possible to use templating and geometric arguments to control the formation of intergrown phases between two polymorphs, leading to the synthesis of the first aluminosilicate intergrowth of the AIE and CHA frameworks.