crystAlzeo · Crystallography-assisted synthesis of zeolites with tailored acid site distributions

This research deals with a long-term objective in zeolite science: the control of acid site distribution by varying synthesis parameters. In most catalytic reactions, the performance of zeolite-based catalysts depends on the distribution of the acid sites at the nanoscale level. The aluminium atoms in the zeolite framework structure are responsible for the formation of the acid sites, so if their distribution can be tailored so can that of the acid sites. In spite of intense interest, no method for controlling the distribution of acid sites has yet been developed. The synthesis strategy I developed during my PhD research has allowed, for the first time, the distribution of acid sites in the zeolite ferrierite to be modified as a function of the organic structure directing agents (SDAs) employed in its synthesis.With the aim of converting this synthesis strategy into a general methodology applicable to any zeolite, an in-depth understanding of the interactions that are established between the organic SDA molecules and the oxygen atoms of the framework is required. This will allow the SDAs appropriate for the control of aluminium distribution in other zeolites to be chosen rationally. Crystallography is a powerful technique for this purpose, as it can provide detailed information about the location of the organic SDAs within the pores of the zeolite, as well as about the location of the framework silicon and oxygen atoms. This innovative use of crystallography, not just to study the zeolites obtained, but also as a tool to facilitate the design of optimal synthesis conditions for other zeolites, ensures that these syntheses will not be carried out in a trial and error basis. The candidate will perform crystallographic studies at the ETH Zürich (host institution), and this training will be a key to the development of her scientific career, as the expertise in structural characterisation of zeolites will be a perfect complement to her solid synthesis background.