Curcumin modified Titanium Dioxide Nanotubes with Enhanced Visible Light Photocatalytic Performance

Abstract

In this study, curcumin modified TiO2 nanotubes (Cur-TNT) were prepared by a modified impregnationelectrochemical anodization method with 0.01, 0.025, 0.05 mM of curcumin concentrations. The physical properties of the Cur-TNT were studied by several techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fouriertransformed infrared spectroscopy (FT-IR), and UV-Vis diffused reflectance spectroscopy (DRS). The XRD patterns data revealed anatase phase for both the TNT sample and the Cur-TNT samples. The high magnification images from SEM technique showed that the TNT sample and the Cur-TNT samples possess nanotube-like structures with an average diameter of 85 nm. The FT-IR spectra exhibited the characteristic bands of the TiO2 and hydroxyl groups on the TNT surface. Instead of hydroxyl groups, the characteristic bands of curcumin were observed on the surface of the Cur-TNT samples. The EDS results complementarily confirmed the existence of Ti, O, C as the main elements of the Cur-TNT samples. Interestingly, the DRS spectra of the Cur-TNT samples extended into the visible region. The photocatalytic properties of the Cur-TNT samples were evaluated from the degradation of methylene blue under visible light irradiation. It was found that the Cur-TNT samples exhibited higher photocatalytic performance than the TNT sample. A possible photocatalytic mechanism has also been proposed.

Brazilein modified zinc oxide nanorods with enhanced visible light-responsive photocatalytic efficiency

“…Using terephthalic acid as a hydroxyl radical ( • OH) scavenger, the formed • OH during the photocatalytic reaction was investigated. The experiment details were similar to the previous work [19,20,32]. The emission peak was at 424 nm under excitation wavelength 315 nm by using fluorescence analysis (Perkin Elmer LS-50B Luminescence Spectrometer).…”

“…The surface chemical compositions of ZnO and Bra-ZnO nanorods were investigated with FTIR as shown in Figure 5. The FTIR spectra of both ZnO and Bra-ZnO nanorods revealed vibration bands of the Zn-O bond at 400 cm -1 to 750 cm -1 [33], the broad band of O-H stretching mode of the hydroxyl group at 3000 cm -1 to 3600 cm -1 [19,33], and O-H bending mode of the hydroxyl group at 1640 cm -1 [19,33]. The results also showed the existence of brazilein molecules on the surface of the Bra-ZnO nanorods, with intensities of C=O at 1415 cm -1 and C=C bands at 1595 cm -1 and C-H band in the aromatic ring within the wavenumber range of 650 cm -1 to 860 cm -1 and aliphatic C-H band at around 2871 cm -1 to 2925 cm −1 were also observed [34][35][36].…”

“…However, the application of pure ZnO in photocatalysis under visible and solar light is restricted due to its wide band gap and quick recombination of electron-hole pairs [6,7]. To solve these drawbacks, many researchers developed various methods, such as metal and nonmetal doping [8][9][10][11], coupling with other narrow-band gap semiconductors [12][13][14] and dye-sensitized semiconductors [15][16][17][18][19][20]. The use of dye molecules to sensitize ZnO particles is considered to be an effective way to expand light absorption into the visible region while also improving their photocatalytic activities.…”

Double layer lanthanide –Pt/TiO2 nanotube arrays electrode as a cost-highly efficient electrocatalyst for hydrogen evolution in acid media

“…Normally, the formation of TNTAs during anodization process depends on three simultaneous reactions. The first is field-assisted oxidation of Ti metal to form TiO 2 , followed by field-assisted etching of the oxide layer by the electric field weakening the bond between Ti and O, and cause the chemical dissolution of TiO 2 by fluoride ions [26]. The presence of fluoride ions in the electrolyte is due to migration through the oxide film to form water soluble [TiF 6 ] 2species, Equation (6), or due to chemical attack of the formed TiO 2 , Equation (7) [27][28][29][30].…”

TiO2–Au composite nanofibers for photocatalytic hydrogen evolution

“…6b, the Tauc plots based on the UV-vis curves determine the band gaps, that are 3.15 eV and 2.75 eV for TiO 2 NFs and TiO 2 -Au composite NFs, respectively. 43,44 The reduced band gap of TiO 2 -Au composite NFs suggests that the presence of gold NPs can effectively increase the absorption edge and enhance the photocatalytic efficiency. It is also bene-cial for extending the light absorption to the visible light range, that is one of the vital factors to improve the photocatalytic H 2 generation performance.…”