Fig. 5. Study on photoexcitation process and photocatalysis mechanism.

a EPR signals of the reaction solution under the dark and light irradiation in the presence of DMPO and TEMP as the spin-trapping reagents. b TA spectra of 9-AC, H₄BTTD, and CeBTTD-A were probed within the region of 850–1350 nm. Excitation wavelength: 9-AC (340 nm), H₄BTTD (400 nm), and CeBTTD-A (400 nm). c The kinetic traces of 9-AC, H₄BTTD, and CeBTTD-A were probed at 1100 nm. d Proposed mechanism for aerobic oxidation of C(sp³)–H bonds by CeBTTD-A.