Synthesis, characterization and photoluminescence properties of tetra(aminophenyl) porphyrin covalently linked to multi-walled carbon nanotubes

Abstract

Synthesis of a new nano hybrid of 5,10,15,20-mesotetra(4-aminophenyl) porphyrin (TAP) functionalized with multi-walled carbon nanotubes (MWCNTs) through an amide linkage is reported for the first time. This MWCNT-TAP hybrid was characterized by Raman, Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA), absorption and emission spectroscopy. TGA analysis reveals that there is a ∼60% weight loss when heated from 150-750 • C, which is attributed to the amount of TAP molecules that were attached to MWCNTs. Electronic properties of MWCNTs were improved in the hybrid compared to raw MWCNTs as evidenced by Raman spectra. The absorption and emission spectra of TAP and nano-hybrid indicate strong positive solvatochromism with increasing solvent polarity. Fluorescence quenching of TAP in different solvents were observed in the emission spectra in the MWCNT-TAP hybrid, indicating that covalent functionalization facilitated effective energy or electron transfer from porphyrin moiety to the MWCNT.

Accelerating the Photocatalytic Degradation of Green Dye Pollutants by Using a New Coating Technique for Carbon Nanotubes with Nanolayered Structures and Nanocomposites

“…The G peak position of the treated CNTs‐LDHs (1578 cm −1 ) exhibited a shift to lower frequency (≈3 cm −1 ) compared with untreated CNTs‐LDHs (1581 cm −1 ). In general, hybrid carbon nanomaterials exhibit this type of low‐frequency shift (softening) when functionalized with an electron‐donor molecule . The lower frequency shift observed for the treated CNTs‐LDHs confirmed the charge transfer between the nanocomposite and the CNTs, in which aluminum zinc oxide acts as an electron donor and CNTs act as an electron acceptor.…”

“…In general,h ybrid carbon nanomaterials exhibit this type of low-frequencys hift (softening)w hen functionalized with an electron-donor molecule. [35,38] The lower frequencys hift observed fort he treated CNTs-LDHsc onfirmed the charget ransfer between the nanocomposite and the CNTs, in whicha luminum zinc oxide acts as an electron donor and CNTsa ct as an electron acceptor.T his lower-frequency shift and the higher ratio of the Da nd Gb and intensitiesr evealed the functionalization and coatingo fC NTsw ith aluminum zinc oxide nanocomposite and confirmed their vital role in accelerating photocatalytic reactions (discussedb elow). This explana- tion agreesw ith the findings of previousr esearchers, who reported that the Gband shifted to al ower wavenumber and the I D /I G ratio increased when CNTsw ere coupled with metal oxides because of the electron-donor characteristics of metal toward the CNTs.…”

“…Its intensityr elative to the Gband is often used to determine the quality of nanotubes. The I D /I G ratio of pure CNTsi s0 .8 to 0.9, [35,36] whereas the ratio for CNTs-LDHs was 1.6, which indicatesa ne nhancement in the Dpeak relative to pure CNTs. This enhancement is believed to be due to disorders and defects associatedw ith the process of coating LDHs onto CNTs.…”

Co(II) Porphyrin-MWCNT Nanoconjugate as an Efficient and Durable Electrocatalyst for Oxygen Reduction Reaction

“…The peaks at 1634 and 1461 cm −1 in CoTPP-NH 2 are assigned to the vibrations of benzene and pyrrole ring skeletons. 32 Thermogravimetric Analysis (TGA). To know the degree of functionalization of porphyrin on MWCNTs, we performed the thermogravimetric analysis technique in a nitrogen atmosphere (Figure 3).…”

Multiwall Carbon Nanotubes Non-covalently Functionalized by Porphyrin–Sn Networks for Protein Adsorption

“…26 The strong emission peak for the composite MPT is blue-shifted to 601.0 nm without affecting the weaker one at 653.5 nm upon the excitation at 420 nm, which is due to the alteration of the S 1 electronic energy level of TCPP upon the formation of a multilayer TCPP−Sn complex network in the composite. 27 In addition, the formation of the TCPP−Sn complex network also decreases the electron density at the TCPP, which is more conducive to the occurrence of negative solvatochromism, 28 i.e., a blue shift. In addition, as the mass ratio of the MWCNTs increases from 0.2 to 1.0, the fluorescence intensity of MPT is gradually quenched, which is similar to the UV−vis absorption trend, which is ascribed to the photoinduced electron/energy transfer from the TCPP−Sn complex to MWCNTs.…”