Nitrogen/Palladium-Codoped TiO₂for Efficient Visible Light Photocatalytic Dye Degradation

Abstract

Elimination of toxic organic compounds from wastewater is currently one of the most important subjects in water pollution control. Eosin Yellow, an anionic xanthene fluorescent dye, known to be carcinogenic, originates mainly from textile industrial processes and is resistant to conventional chemical or biological water treatment methods. Photocatalysis using non metal/platinum group metal-codoped TiO2 may provide effective means of removing such dyes from contaminated water. In this study, nitrogen/palladium-codoped TiO2 photocatalysts were prepared by calcination of the hydrolysis product of titanium isopropoxide, Ti(OC3H7)4, with aqueous ammonia. Samples were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), diffuse reflectance UV–vis spectrophotometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Anatase phase particles of size range 10–20 nm were confirmed by XRD, Raman, TEM, and SEM analysis. Codoping imparted a red shift in the absorption edges of the materials. Codoped TiO2 showed greater photocatalytic Eosin Yellow degradation efficiency compared to singly doped N–TiO2 or Pd–TiO2 under visible light irradiation. The highest initial reaction rate of 2.238 × 10–2 min–1 was observed for N/Pd–TiO2 (0.8% Pd). The results demonstrated that the N/Pd-codoped TiO2 (0.6% Pd) sample could completely degrade the dye in 3 h, while the commercial TiO2, (Degussa P25) showed the lowest dye degradation efficiency.

A review on plasmonic metal⿿TiO2 composite for generation, trapping, storing and dynamic vectorial transfer of photogenerated electrons across the Schottky junction in a photocatalytic system

“…The high photoactivity of Pd/N-TiO 2 (0.6% Pd) for eosin yellow decomposition under visible light arises from the synergistic effects of palladium deposition and nitrogen doping [198]. The palladium on TiO 2 surface creates a Schottky junction between the metal and the semiconductor, which acts as a sink for photogenerated electrons.…”

Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

“…Doping NTO with metals and non-metals creates new energy levels between the VB and CB of TiO 2 [121], which in turn reduces its band gap and helps the doped catalyst to absorb in the visible region (Figure 4). Recently, researchers have reported the successful doping of vanadium [122], iron [123], rhodium [50], palladium [124], and silver [125] metals, and carbon [105,126], nitrogen [51,96,105,121,124,127,128], sulfur [98,129], fluorine [96], and iodine [130] non-metals in NTO to achieve the visible light photocatalytic degradation of various chemicals and Escherichia coli in aqueous solution (Table 3). In all reports, except in silver doping, the visible light photocatalytic activity was mainly attributed to the associated red shift that originated from the creation of local bands between the VB and CB of NTO (Figure 4).…”

Photocatalytic degradation of tetracycline using nanosized titanium dioxide in aqueous solution

“…Doping TiO 2 with metals or non-metals can decrease the band gap of the doped catalyst and makes possible the light absorption in the visible region. The improved catalysts seem to be photo-stable in aqueous solution and can be used in photocatalytic water purification (Kuvarega et al 2011;Barolo et al 2012). 5.…”