Co-templated synthesis of zeolites for applications in adsorption and catalysis

Lead Research Organisation: University of St Andrews
Department Name: Chemistry

Abstract

Zeolites are microporous aluminosilicates with applications in gas adsorption and catalysis, prepared hydrothermally using inorganic or organic cations to direct or template the framework crystallisation.

This project aims to develop co-templating routes in which inorganic and organic cations are used together to prepare zeolites with new structures or compositions. The work will include the characterisation of a series of flexible (RHO-type) zeolites, prepared using different metal and tetraethylammonium cations that show highly selective gas adsorption. Using the principles derived from this, other zeolite syntheses will then be devised using combinations of cations and other small organics to give small pore low Si/Al zeolites valuable in gas separations, including merlinoite and phillipsite.

The structures will be measured in situ during gas separations. Elliott Bruce, as the best MChem student graduating this year, is uniquely placed to perform these complex analyses. Existing in situ synchrotron X-ray powder diffraction data is available on the complex RHO family structures ZSM-25 and PST-20 with and without adsorbed carbon dioxide and initial structural studies will involve their refinement using the TOPAS program, required for such complex structures. This will enable the determination of cation locations and so help understand, in combination with computational studies, their selective adsorption behaviour for a range of industrially relevant separations. Additionally, further X-ray and neutron diffraction data will be collected on zeolite Rho itself, for mixed cation systems that have been found to be of interest for industrial separations with a collaborating industrial company.

Further, co-templating routes to zeolites with high Si/Al required for stable auto-exhaust catalysts will be devised. Several promising materials have been prepared using highly expensive organic templates. Here, the aim is to use combinations of inorganic and less-expensive organic templates to make such catalysts more accessible, making use of computational modelling for template design. This is of great interest to Johnson Matthey, so the project will be conducted in collaboration with them, giving Elliott insight into industrial catalytic chemistry and access to their extensive facilities at Billingham.

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R512199/1 30/09/2017 29/09/2021
1947940 Studentship EP/R512199/1 26/09/2017 14/10/2023 Elliott Leigh Bruce
 
Description The structural behaviour of some small pore zeolites in relation to their novel gas adsorption properties has been investigated. Additionally, some effects of mixed-templated sysnthesis have been observed in the desired synthesis system.
Exploitation Route Investigation of the adsorption properties of the same materials with different cation content may be carried out and may show interesting behaviour. There is great potential for using different organic and inorganic templates in synthesis systems to tailor the structures of synthesis products.
Sectors Chemicals,Environment

 
Description Science Discovery Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Over 600 people, mostly from Fife and neighbouring regions, largely children and their parents, attended the event at the University. We provided one of the larger exhibits at the event which sought to enthuse the public, especially children, in science in general. We specifically talked to people about the structures of zeolites and crystals on the atomic, microscopic and macroscopic scales as well as their potential role in carbon capture and the climate crisis. This was also carried out in partnership with colleagues from the University of Edinburgh School of Engineering who brought a display piece showing the process of carbon capture and storage. Many people came and actively interacted with our stall, especially children who were excited to build their own models of crystal structures, as well as look through microscopes.
Year(s) Of Engagement Activity 2019