Research Information System
SURFACES AND INTERFACES, 2025 (SCI-Expanded)
A porphyrinic Ti based MOF (Ti-TCPP) as a superior, robust photocatalyst providing much higher dye degradation rate with almost complete mineralization was synthesized for the first time using tetrakis (4-carboxyphenyl) porphyrin (TCPP) as the organic ligand. The band-gap energy of Ti-TCPP was calculated as 1.65 eV via Tauc plot. The ratio of oxygen vacancy to the lattice oxygen and Ti(III)/Ti(IV) atomic ratio were determined as 0.526 and 0.539, respectively. The generation of singlet oxygen (O-1(2)) and superoxide anion (O-2(-)center dot) radicals by Ti-TCPP irradiated with VL was shown by ESR spectroscopy. Ti-TCPP was evaluated as a catalyst in VL driven-degradation of RhB. The time periods for complete removal of RhB were ca. 40, 60 and 120 min with the initial RhB concentrations of 20, 50 and 100 mg/L, respectively. The highest degradation rate was obtained at the natural pH of the degradation medium (i.e. pH 4.5). At this pH, Ti-TCPP and RhB exhibited positive and negative charges, respectively, causing electrostatic attraction between the photocatalyst and the pollutant leading to faster degradation. Total organic carbon content of the degradation medium was reduced to 3.4 % of the initial value within 24 h using the initial RhB concentration and the Ti-TCPP concentration of 20 mg/L and 0.05 mg/mL, respectively. With respect to the current photocatalysts, higher degradation rates providing almost complete removal of RhB in shorter times were achieved even if the RhB concentration was higher (i.e. > 50 mg/L) and the photocatalyst concentration was much lower (i.e. 0.05 mg/mL). The highest apparent first order rate constant for RhB degradation was obtained as 0.1587 min(-1). A total decrease of 20.7 % was observed in the removal yield of RhB over ten consecutive degradation runs performed at pH 4.5. A photodegradation pathway was proposed based on High Resolution Mass Spectroscopy analysis. This analysis demonstrated that fast de-ethylation was an important property of the photocatalytic degradation catalyzed by Ti-TCPP.