May Molecule of the Month

May 2023’s Molecule of the Month is cobalt(II) phthalocyanine (CoPc)! In the latest report of light-driven CO₂ reduction with this catalyst, CoPc was noncovalently immobilized on cadmium sulfide (CdS)-dispersed carbon nanotubes (CNTs). The CdS light absorbers generated electron-hole pairs, and the electrons were rapidly transferred from the CdS through the CNTs to the CoPcs for selective CO₂-to-CO conversion. These proposals were supported by ultrafast transient absorption (TA) measurements of CdS exciton bleaching. Moreover, systems without the CoPc or CdS did not demonstrate CO formation, and a CdS/CoPc system was both much slower and much more biased towards H₂ formation than the fully constituted ternary hybrid catalyst. Additionally, the CNT created local photothermal heating for the conversion of amine-captured CO₂ to CO without other energy inputs. In situ Raman spectra during CO₂RR revealed that CoPc was observed during light-driven CO formation, implicating it as the active species. In situ UV-Visible spectroscopic studies showed doubly-reduced catalyst CoPc reacted almost immediately with CO₂ to generate singly-reduced CoPc, consistent with complementary Raman experiments. The CHASE collaboration was lead by Hailiang Wang’s group with spectroscopic measurements from Tim Lian’s laboratory and additional contributions from Judy Cha’s group.

Check it out at https://doi.org/10.1002/anie.202302152 !