Understanding Copper–Zinc Synergy for Carbon Dioxide Hydrogenation

ended

Carbon dioxide (CO2) is a greenhouse gas that is significantly contributing to climate change. In tandem with advances in sequestering carbon, beneficial uses for CO2 are of high societal importance for developing a sustainable future. One attractive use of CO2 is in its conversion to energy dense fuels (green energy vectors). One such fuel is methanol, made from CO2 via hydrogenation in conjunction with a multimetallic catalyst. The current best industrial (heterogeneous) catalyst incorporates copper and zinc-oxide nanoparticles with an alumina support. A special synergy is observed between the copper (active site) and zinc (reaction promoter), but these species and their connection is poorly defined and remains debated. This project aims to isolate proximal copper and zinc centres, the fundamental building block for the construction of critical copper–zinc interfaces, within a well-defined, and highly tuneable ligand framework. Once isolated, the binding, activation and interconversion of key intermediates along the CO2 hydrogenation pathway will be meticulously analysed. Work package 1 involves the synthesis and characterisation of a series of 12 ligands that encompass a range of stereo-electronic profiles, and subsequent isolation of CuZn complexes using these ligands. Work package 2 will use the complexes to study the activation and interconversion of key intermediates along the CO2 hydrogenation pathway to gain mechanistic understanding. Finally, work package 3 will test the most active complexes as catalysts for the direct hydrogenation of CO2 to methanol. The combination of my skills (multimetallic systems) and the host groups (mechanistic studies) make achieving the project aims realistic. The knowledge harnessed from gaining deep mechanistic understanding of the synergy between copper and zinc during CO2 hydrogenation will be invaluable in developing the next generation of catalysts for methanol production, adding value to a deleterious waste streams.