Scientists have successfully developed an innovative metal-organic framework (MOF) that is great at boosting the conversion of photocatalytic CO₂ into C2 products, and this technique could be potentially effective in addressing the energy crisis and carbon neutrality.
Using Delocalized Orbitals
What allowed the researchers to make their breakthrough is a carefully considered MOF compound, PFC-98. Through careful control of the building units they have created a structure with delocalized orbitals spanning across both the metal cluster and organic linker.
This provides a route for a rapid direct charge transfer process giving an optimized way to enhance electron transfer/ separation efficiency. Theoretical calculations show that the lowest unoccupied molecular orbital (LUMO) energy levels of the ligand and cluster are well aligned in PFC-98, leading to efficient charge transfer from ligands to metal clusters via direct electron excitation.
This efficient charge transfer process results in the generation of a long-lived intermediate charge-separated state upon photoexcitation, which is corroborated by spectroscopy investigations. These long-lived excited states and high eff¬iciency of electron/hole separation are essential to enhance the photocatalytic activity in the protocell.
Highly Efficient CO₂ Phоtосаtаlуtiс Turn Around
The PFC-lo98 MOF exhibits photocatalysis properties (Fig. 3B and table),. These were 58.14 μmol g−1 h−1 for acetate and 43.14 μmol g (g)-1 h(-1) for ethanol production in the combined CO2 photoreduction.
This level performance is better than that of nearly all materials reported to date for any catalytic process, demonstrating the promise of this MOF design. The scientists showed that this extraordinary performance is due to the electron density augmentation on the metal cluster accelerating C2 formation from CO₂ photocatalytic reaction.
The electron-deficient linker 2,5-di(1H-pyrazol-4-yl)thiazolo[5,4-d]thiazole (PyTT) was strategically incorporated into the MOF structure to significantly improve the photoCatalytic activity compared with its isoreticular counterpart constructed using H2DPB.
Conclusion
The research team’s pioneering work reveals new perspective for photocatalytic CO₂ reduction to produce C2 products. By exploiting the unique properties of the PFC-98 MOF, they showed a dramatic improvement in this critical process to bring about more sustainable means for meeting the energy challenge and carbon neutrality goals on a scale-expanding level.
