Comparison between Base Metals and Platinum Group Metals in Nitrogen, M Codoped TiO₂ (M = Fe, Cu, Pd, Os) for Photocatalytic Removal of an Organic Dye in Water

Abstract

The photocatalytic performance of a number of nonmetal and metal codoped TiO2for the degradation of eosin yellow under simulated solar radiation was investigated. The synthesised materials were characterised by FTIR, Raman spectroscopy, XRD, DRUV-Vis, SEM, and TEM. The N, metal codoped TiO2containing 0.5 wt.% of the metal consisted mainly of the anatase phase, with a particle size range of 15–28 nm. The particles were largely spherical and shifted the absorption edge well into the visible region. Band gap reduction was more pronounced for the N, PGM codoped TiO2compared to N, base metal codoped samples. Codoping led to an enhancement in the photocatalytic activity of the materials for the degradation of eosin yellow. N, Pd codoped TiO2was the most effective photocatalyst (99.9% dye removal) while N, Cu codoped TiO2showed the least activity (25.5% removal). The mechanism for the photocatalytic enhancement was proposed on the basis of formation of an electron deficient Schottky barrier at the semiconductor-metal interface, which acts as an electron sink and thus retards electron-hole recombination. It was shown that the ability of the photocatalyst to degrade the dye depends on the nature and type of the metal dopant in the codoped TiO2system.

One-Electron Water Oxidation Intermediate on TiO2 P25 Probed by Ultrafast Attenuated Total Reflection

“…As shown in Figure b, FTIR spectra show several vibrational features with 3500 cm –1 due to surface hydroxyl stretch and broad features below 1000 cm –1 . Such broad features might be due to Ti–O stretches that have vibrational frequencies near 700–900 cm –1 , or broad electronic absorption due to dopants such as oxygen vacancies . Also, since the P25 we are using is a mixture of rutile and anatase, the vibrational frequency could be broad due to the presence of multiple Ti–O species.…”

Choline Chloride Assisted Synthesis of N and Metal Codoped TiO2 and their Photocatalytic Activity under Visible Light

“…Kuvarega et al . also reported the effect of metals (Fe, Cu, Pd, Os) on the photocatalytic activity and concluded that the ability of the photocatalyst to degrade the dye depends on the nature and type of metal dopant in the codoped TiO 2 system .…”

Enhancing Charge Transfer in Photocatalytic Hydrogen Production over Dye-Sensitized Pt/TiO2 by Ionic Liquid Coating

“…FTIR spectra of the synthesized photocatalysts are given in Figure . The FTIR spectra of TiO 2 and Pt/TiO 2 particles are nearly the same, indicating that Pt impregnation did not affect the physical state of TiO 2 as it was expected. , The broad peak between 500 and 1000 cm –1 is due to the Ti–O and Ti–O–Ti stretching modes. , Peaks at 1630 cm –1 and the wider peak at around 3300 cm –1 were attributed to the H–OH bending and the O–H stretching of the hydroxyl group, respectively. The hydroxyl groups on the surface of P25 and water adsorbed by the surface enhance the photocatalytic water splitting since they prevent the recombination reaction and promote charge transfer by acting as molecular adsorption and hole scavenging sites; − the peaks at 1630 and 3300 cm –1 are also apparent in other photocatalysts.…”