Heterobimetallic Polymerisation Catalysts - Understanding Metal Synergies in Circular Economy Plastics Production

Chemical transformation of non-toxic, inexpensive and abundant carbon dioxide to valuable products and materials is a highly attractive method of carbon dioxide (CO2) utilisation. Polymers (which are the major component in plastics) represent an important class of materials that can be made using CO2.
CO2-derived polymers show significant potential for use in a wide range of applications. For example, these polymers can be used as surfactants (in home and personal care), as electrolytes in batteries and as a replacement for petrochemical-based polymers in the production of polyurethanes. The resulting CO2-derived polyurethanes can then be applied in the manufacture of consumer goods (such as footwear and mattresses) and in the production of sealants, adhesives and coatings. Furthermore, CO2-derived polymers are more easily recycled than polymers derived entirely from petrochemicals, making application of these materials an important part of our transition to a circular material economy.
In order to achieve chemical transformation of CO2, which is normally unreactive, a catalyst is required. Since the late 1960s, considerable effort has gone into developing more efficient, higher performance catalysts for the production of polymers from CO2. The best catalysts often employ cobalt, which is expensive to mine due to its relatively low crustal abundance. In addition, cobalt-based catalysts may be toxic, which is a disadvantage when considering that small amounts of catalyst residue can remain in the final polymer product.
Selection of the optimum catalyst involves a trade-off between, primarily, performance and cost. Therefore, it would be of considerable interest to develop high-performance catalysts employing cheaper and more earth-abundant metals. Iron is a promising candidate due to its lower cost, general biocompatibility and high crustal abundance, which is around 2000 times that of cobalt. However, iron-based catalysts often show inferior performances relative to cobalt-based catalysts.
The aim of this project is to synthesise a high-performance, iron-based catalyst for polymer production from CO2. In addition, a wide range of analytical techniques will be used to probe the underlying catalytic mechanisms and gain information on the key attributes of a high-performance catalyst. Subsequently, this information will be used to develop a set of 'rules' or guiding principles to inform a targeted approach to future
catalyst design.
This project falls within the EPSRC "catalysis" research area.
Inorganic Chemistr