Light-Matter Interactions in Porous Material Photocatalysts for Green and Sustainable Organic Synthesis
- Date: Monday 12 May 2025, 14:00 – 15:00
- Location: Online
- Cost: None
Dr Ipsita Nath Department of Chemistry, Ghent University, Krijgslaan 281, Building S3, Ghent, https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZWRmMzc0MmQtYzUwMi00YWI3LWFiMGMtYjQ5MmYxZGUzNjk2
Dr Ipsita Nath
Department of Chemistry, Ghent University, Krijgslaan 281, Building S3, Ghent, Belgium, 9000 inath.nath@ugent.be; ipsita.nath@hotmail.com
Metal Organic Frameworks and Covalent Organic Frameworks (MOFs and COFs) are emerging classes of crystalline polymeric materials featuring programmable chemical design, robust backbone, permanent nano-porosity, and high surface area. A combination of these properties has poised MOFs and COFs as exciting candidates for gas adsorption and heterogeneous catalysis. Recently, organic photo-active moieties are being used to synthesise these materials as conjugated heterogeneous platforms merging traditional photocatalysis with high surface area, ordered channels, and pores. These pores with densely decorated photocatalytic units serve as nano-reactors by integrating efficient mass flow and interfacial charge transfer, ergo augmented catalytic activity.
Due to such beneficial features, these porous materials are being explored for various photocatalytic applications. However, the fundamental structure-property relations catering to the photocatalytic activities of the materials remained empirical and underexplored. The extended conjugation is speculated to instigate a semiconducting nature in these porous systems that append an added attribute to the spatiotemporal charge dynamics. Therefore, a detailed analysis of the formation, delocalization, and decay of the excited-state species, e.g., excitons, excimers, trap- and free-charges, etc. in these materials and their impact on the interfacial charge transfers can help us understand the holistic photocycle and the photocatalysis process from a fundamental perspective across both length- and timescale. Parallel to the fundamental understanding, it is also important to simultaneously develop dedicated processes to increase the TRL of the catalytic methods and achieve a lasting academic, environmental and economic impact.
In this seminar, I will report snippets of various case studies from my research on this ensemble topic. Initially, I will talk about the development of porous material photocatalysts for carbon-carbon and carbon-heteroatom bond formation reactions and the strategies I adopted to increase their substrate scopes to even non-activating compounds. I will also discuss the development of a customised flow reactor that allows immediate access to pure products on multiple runs using these catalytic systems. These works will highlight the importance of suitable catalyst developments and their tangible, practical utilisation. This will be followed by detailed photophysical analysis of these materials using a combination of time-resolved spectroscopic techniques, including ultrafast transient absorption spectroscopy. These analyses helped us recognise the excited states and species involved in the photocatalysis, e.g., excitons, excimers, trap states, etc., as well as their formation and decay dynamics, which can be associated with the chemical and physical/microscopic structure of the materials. These spectroscopic data complement the catalytic results and give us unprecedented molecular-level insights, which are highly beneficial and pivotal to predefine the material design rules for targeted photocatalytic applications. Finally, I will briefly introduce my future research goals of capturing and simultaneously photochemically converting CO2 and other greenhouse gases into value-added organic products and discuss how my present research has created various avenues towards that.