Role of metal (Fe(III), Zn(II), and Co(III)) and porphyrin in enhancing photocatalytic performance of MTCPP/TiO2 photocatalysts

[Display omitted] •Novel biomimetic-inspired porphyrin modified TiO2 (MTCPP@P25) were synthesized as visible-light driven photocatalytic.•Porphyrin effectively narrows down the band gap of TiO2 from ultraviolet to visible light range.•Metals in porphyrin determine the photocatalytic performance of MTCPP@P25 due to the change of electron distribution.•The degradation order for MB was FeTCPP@P25≧ZnTCPP@P25 > CoTCPP@P25.•FeTCPP@P25 exhibits longest lifetime and fastest electron transition rate. Metal-porphyrin complexes modified TiO2 photocatalyst, called MTCPP@P25, shows excellent photocatalytic activity under visible light irradiation. Metal-porphyrin is successfully utilized to broaden the photo response range of TiO2 from ultraviolet (3.2 eV) to visible light (2.43 eV to 2.65 eV) resulting in significant enhancement of photocatalytic efficiency. MTCPP@P25 exhibited the higher photocatalytic activity than bare TiO2. Additionally, introduction of different metals, like Fe, Zn, and Co into porphyrin ring can effectively adjust the photocatalytic activity of MTCPP@P25 due to the increasing the electron density of porphyrin rings. The degradation order for MB followed as FeTCPP@P25≧ZnTCPP@P25 > CoTCPP@P25. This finding demonstrated that FeTCPP@P25 and ZnTCPP@P25 possess higher photo-excited electrons under visible irradiation resulting in higher photocatalytic performance. Based on the PL and EIS analysis, FeTCPP@P25 exhibited longest lifetime and fast electron transition compared to ZnTCPP@P25. The spent FeTCPP@P25 were reusable after three cycles, the efficiency remained at approximately 80 %.