Enhancement of Visible Light-Responsive Photocatalytic Efficiency by Using a Laccaic Acid-Modified Titanium Dioxide Photocatalyst

Abstract

In this study, a laccaic acid-modified TiO2 photocatalyst (Lac-TiO2) was prepared via an impregnation method with 0.50, 1.00, 2.50, and 5.00 wt.% laccaic acid. The products’ physical properties were examined through X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoemission spectroscopy (XPS), UV-Vis diffused reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption, and photoluminescence (PL) spectroscopy. A possible photocatalytic mechanism was also proposed. XRD patterns revealed the anatase phase of TiO2 and Lac-TiO2 samples. High-magnification FE-SEM images showed that the TiO2 and Lac-TiO2 samples exhibited spherical-like structures. XPS results complementarily confirmed the presence of Ti, O, and C as the main elements of the Lac-TiO2 samples. Interestingly, the DRS spectra of the Lac-TiO2 samples extended into the visible region. FTIR spectra presented the characteristic bands of TiO2 and hydroxyl groups on the TiO2 surface. Instead of hydroxyl groups, the characteristic bands of laccaic acid were observed on the surface of the Lac-TiO2 samples. The photocatalytic properties of the Lac-TiO2 samples were evaluated in terms of methyl orange degradation under visible light irradiation. The Lac-TiO2 samples showed higher photocatalytic performance than the TiO2 sample.

Carbon Dots Modification Surface of Titanium Dioxide and Their Photocatalytic Activity

“…The highest activity was observed in the 1.0wt%C-dots/TiO2 samples indicating that the modification of c-dots onto the TiO2 surface significantly enhanced the photocatalytic activity. The high loading c-dots content decreased the photocatalytic efficiency [26,27]. At higher c-dots content, the agglomerated c-dots could become a recombination center of electron-holes that produced lower photocatalytic degradation efficiency.…”

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).…”

“…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.…”