| Autor: |
Knapp JG; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Livshits MY; Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States., Gilhula JC; Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States., Hanna SL; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Piedmonte ID; Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States., Rice NT; Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States., Wang X; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Stein BW; Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States., Kozimor SA; Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States., Farha OK; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.; Department of Chemical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States. |
| Abstrakt: |
While uranyl-based metal-organic frameworks (MOFs) boast impressive photocatalytic abilities, significant questions remain regarding their excitation pathways and methods to fine-tune their performance due to the lack of information regarding heterogeneous uranyl catalysis. Herein, we investigated how linker identity and photoexcitation impact uranyl photocatalysis when the uranyl coordination environment remains constant. Toward this end, we prepared three uranyl-based MOFs ( NU-1301 , NU-1307 , and ZnTCPP-U2) and then examined the structural and photochemical properties of each through X-ray diffraction, X-ray absorption, and photoluminescence. We then correlated our observations to the photocatalytic performance for fluorination of cyclooctane. The excitation profile from NU-1301 and NU-1307 exhibited spin-forbidden linker transitions and uranyl vibronic progressions, with uranyl excitation and emission being most dominant in NU-1301 . Consequently, NU-1301 was a more active photocatalyst than NU-1307 . In contrast, the excitation profile from ZnTCPP-U2 contained transitions associated with the porphyrin linker exclusively. Photocatalytic activity from ZnTCPP-U2 significantly underperformed in comparison to that of the other two MOFs. These data suggest that linkers' photophysical properties can be used to predict the photocatalytic behavior of uranyl-containing MOFs. |
