The visible light degradation activity and the photocatalytic mechanism of tetra(4-carboxyphenyl) porphyrin sensitized TiO_2

摘要

Tetra(4-carboxyphenyl) porphyrin(TCPP) were chemically sensitized on TiO_2 to act as visible light antenna and to modify the photoresponse properties of TiO_2 particles, their properties of photogenerated holes and electrons were studied by transient absorption spectroscopes. The time-correlated single-photon counting (TCSPC) technique revealed that the S2-S0 fluorescence intensity of TCPP is enhanced noticeably by TiO_2, and the lifetime prolonged. Adsorption and photo degradation of methylene blue (MB) over TCPP-TiO_2 were systematically investigated. Moreover the overall picture of electronic relaxation dynamics for TCPP-TiO_2 is presented, and the detailed short-time dynamics for visible-light induced catalytic mechanism was discussed. The development of the porphyrin-based photocatalyst provides an alternative approach in harnessing solar visible light and show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application.