N-Doped TiO₂ Nanoparticle Based Visible Light Photocatalyst by Modified Peroxide Sol−Gel Method

Abstract

The peroxide gel route is employed to synthesize N-doped TiO2 nanoparticles (NP) at low temperature using titanium tetraisopropoxide, ethylmethylamine, and hydrogen peroxide as precursors. Structural studies show anatase phase in the undoped titania NPs as well as at 5 at. % N-doped titania NPs, although with a degree of matrix disorder in the latter case. The annealing of N-doped titania NPs at different temperatures shows that above 400 °C nitrogen escapes the O−Ti−O matrix and at 500 °C the sample becomes crystalline. Transmission electron microscopy reveals that the particle size is in the range of 20−30 nm for the undoped TiO2 but only 5−10 nm for N-doped TiO2. At higher nitrogen concentration (10 at. %) bubble-like agglomerates form. FTIR and photoluminescence quenching also confirm the incorporation of nitrogen in anatase TiO2. Optical properties reveal an extended tailing of the absorption edge toward the visible region upon nitrogen doping. X-ray photoelectron spectroscopy is used to examine the electronic state of doped nitrogen and the associated possible electronic modification of the TiO2 matrix. Under visible light irradiation the undoped TiO2 NPs do not show any significant photocatalytic activity, as expected; however, the 5 at. % N-doped TiO2 NPs show excellent activity.

Synergistic effect of Ag deposition and nitrogen doping in TiO2 for the degradation of phenol under solar irradiation in presence of electron acceptor

“…Insertion of N in substitution position in the lattice of titanium dioxide is confirmed by the Vegard's law as mentioned in our earlier work [21]. Ogale et al, have also shown this marginal shift and they have accounted it to the nitrogen incorporation into the TiO 2 matrix [27]. They suggested a significant modification in the electronic states, which takes place due to the replacement of oxygen by nitrogen on N doping.…”

Low-Temperature Sol-Gel Synthesis of Nitrogen-Doped Anatase/Brookite Biphasic Nanoparticles with High Surface Area and Visible-Light Performance

“…To further confirm the existence of anatase and brookite phases, high-resolution TEM (HRTEM) analysis of NA-165 was performed. As shown in Figure 2a [30]. Moreover, the Ti 2p2/3 and Ti 2p1/2 core levels were located at 458.4 and 464.2 eV (Figure 3b), which shift toward lower binding energies as compared to the reported pure TiO2 due to the nitrogen doping [31].…”

“…The XPS results along with XRD patterns and HRTEM images reveal that nitrogen-doped anatase/brookite biphasic nanoparticles were successfully synthesized. [30]. Moreover, the Ti 2p2/3 and Ti 2p1/2 core levels were located at 458.4 and 464.2 eV (Figure 3b), which shift toward lower binding energies as compared to the reported pure TiO2 due to the nitrogen doping [31].…”

“…The absorbance of the N-doped samples was stronger than that of P25 in the visible light region. The band gap energies of NA-185, NA-165, NA-145, HA-165, and P25 were 3.05, 3.03, 3.01, 3.09, and 3.12 eV, respectively, which were calculated from Equation (1): [30]. Moreover, the Ti 2p2/3 and Ti 2p1/2 core levels were located at 458.4 and 464.2 eV (Figure 3b), which shift toward lower binding energies as compared to the reported pure TiO 2 due to the nitrogen doping [31].…”

Silver metalized mixed phase manganese-doped titania: Variation of electric field and band bending within the space charge region with respect to the silver content

“…The peak in the spectrum arises due to the recombination of the free charge carriers [15,[23][24][25][26][27]. Many binding states exist between CB and VB which are created due to the presence of defects such as oxygen vacancies, surface states and other impurities like dopant [28].…”