Fluorine‐doped TiO₂ nanoparticles sensitized by tetra(4‐carboxyphenyl)porphyrin and zinc tetra(4‐carboxyphenyl)porphyrin: Preparation, characterization, and evaluation of photocatalytic activity

Abstract

In this study, TiO2 nanoparticles have been doped with fluorine (F‐TiO2) and consequently sensitized with tetra(4‐carboxyphenyl)porphyrin (TCPP/F‐TiO2) or zinc tetra(4‐carboxyphenyl)porphyrin (ZnTCPP/F‐TiO2) to extend their light absorption into the visible region. The prepared photocatalysts were characterized by SEM, XRD, FTIR, and UV‐Vis assays. F‐TiO2 nanoparticles were completely in anatase phase with particle size range of 50−200 nm. Fluorine‐doping of the TiO2 nanoparticles led to a red shift in their absorption spectrum, while did not significantly changed their band gap (from 2.9 to 2.8 eV). ZnTCPP/F‐TiO2 and particularly TCPP/F‐TiO2 nanoparticles displayed improved visible light absorbency with decreased band gap values (1.5 and 2.4 eV, respectively). The photocatalytic activity of the nanoparticles has been studied through degradation of Rhodamine B in aqueous media under UV and visible light irradiation. The prepared photocatalysts showed lower activity than Degussa P‐25 under UV light irradiation. However, under visible light irradiation, F‐TiO2 nanoparticles better photocatalyzed the RhB degradation than Degussa P‐25. Meanwhile, ZnTCPP/F‐TiO2 and mainly TCPP/F‐TiO2 nanoparticles were completely photoactive under visible light irradiation. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1341–1348, 2015

Influences of Doping on Photocatalytic Properties of TiO2 Photocatalyst

“…The origin of the visible light activity of F-doped TiO 2 has been systematically investigated by many researchers via comprehensive theoretical and experimental studies [134,[143][144][145]. It is widely accepted that the three-coordinated surface F atoms with higher 1s binding energy are identified to be the origin of the visible light activity.…”

Synergistic Effect of Fluorinated and N Doped TiO2 Nanoparticles Leading to Different Microstructure and Enhanced Photocatalytic Bacterial Inactivation

“…A single peak is observed; the peak maximum is at 684.5 eV. This peak is attributed to the fluorine anions adsorbed at the surface of the nanoparticles (surface fluorination, i.e., to a terminal Ti–O–F or Ti–F bond), if we compare with literature data [ 44 ]. Furthermore, Senna et al, whom worked also with PTFE as a source of fluorine ion, attributed the peak at 684 eV to a change in electronic states due to fluorine incorporated into P25 near the surface region [ 28 ].…”

Visible‐Light Response and High‐Efficiency Photocatalytic Elimination of Polycyclic Organic Pollutants of Layer‐By‐Layer Assembled Ternary Nanotubular Catalysts

“…As we known, pure TiO 2 irradiated by UV light (λ<400 nm) can photoexcite electrons and holes, but most of electrons and holes quickly recombine, resulting in low photocatalytic efficiency. However, the H 2 TCPP molecules have the large spectral response range and high quantum yields in visible light, and sensitize the TiO 2 with formation of the Ti−O‐C=O chemical bond to improve light‐harvesting ability of H 2 TCPP‐TiO 2 composites in visible light, and further enhance photocatalytic performance of the H 2 TCPP‐TiO 2 composites . Meanwhile, the CNTs as the electron acceptor and the transporter greatly facilitate transfer of electrons, and greatly improve photodegradation of organic contaminants …”

“…However, the H 2 TCPP molecules have the large spectral response range and high quantum yields in visible light, [13] and sensitize the TiO 2 with formation of the TiÀ O-C=O chemical bond to improve light-harvesting ability of H 2 TCPP-TiO 2 composites in visible light, and further enhance photocatalytic performance of the H 2 TCPP-TiO 2 composites. [28] Meanwhile, the CNTs as the electron acceptor and the transporter greatly facilitate transfer of electrons, and greatly improve photodegradation of organic contaminants. [14] Base on the above results, a possible mechanism for the composite catalysts is proposed, as shown in Scheme 2.…”