Nd/TiO2 Anatase-Brookite Photocatalysts for Photocatalytic Decomposition of Methanol

Abstract

Neodymium enriched TiO2 anatase-brookite powders were prepared by unconventional method via using pressurized hot fluids for TiO2 crystallization and purification. The photocatalysts were tested in the CH3OH photocatalytic decomposition and they were characterized with respect to the textural (nitrogen adsorption), structural (XRD, XPS, and Raman spectroscopies), chemical (XRF), and optical (DR UV-Vis spectroscopy) and photoelectrochemical measurement. All prepared materials were nanocrystalline, had biphasic (anatase- brookite) structure and relatively large specific surface area (125 m2.g−1). The research work indicates that the doping of neodymium on TiO2 photocatalysts significantly enhances the efficiency of photocatalytic reaction. The photocatalytic activity increased with increasing portion of hydroxyl oxygen to the total amount of oxygen species. It was ascertained that the optimal amount of 1 wt% Nd in TiO2 accomplished the increasing of hydrogen production by 70% in comparison with pure TiO2. The neodymium doped on the titanium dioxide act as sites with accumulation of electrons. The higher efficiency of photocatalytic process was achieved due to improved electron-hole separation on the modified TiO2 photocatalysts. This result was confirmed by electrochemical measurements, the most active photocatalysts proved the highest photocurrent responses.

Successful Immobilization of Lanthanides Doped TiO2 on Inert Foam for Repeatable Hydrogen Generation from Aqueous Ammonia

“…% by using Elva X energy-dispersive x-ray fluorescence spectrometer (Elvatech Ltd., Kiev, Ukraine). The resulting value was determined as the average of three measurements [20,22]. The nitrogen adsorption-desorption isotherms of the materials showed a similar shape (IV type of the IUPAC classification, Figure 1a), which corresponded to the mesoporous character of all investigated materials with negligible participation of microporosity.…”

“…The textural, structural, optical, and electronic properties of the studied photocatalysts were characterized by nitrogen physisorption [19,20], powder x-ray diffraction (XRD, Rigaku SmartLab diffractometer, Rigaku, Tokyo, Japan) [19,20], x-ray fluorescence (XRF, Elva X energy-dispersive X-ray fluorescence spectrometer, Elvatech Ltd., Kiev, Ukraine) [20], diffuse reflectance UV-Vis spectroscopy (DRS UV-Vis, GBS CINTRA 303 spectrometer, GBC Scientific Equipment, Braeside, Australia) [20,21], x-ray photoelectron spectroscopy (XPS, VG SCIENTA R3000, Prevac Ltd., Rogów, Poland), Raman spectroscopy with a difference 532 nm laser source was used, electron paramagnetic resonance (EPR, EMXplus, Bruker, Bruker Daltonics Ltd., Billerica, Massachusetts, USA), and photoelectrochemical measurements [19]. More details are given in the mentioned references.…”

“…In principle, another reason for changing the value of the band gap energy could be the presence of different phases of titanium dioxide. However, the preparation of these materials always led to the presence of the pure anatase form in TiO 2 , La/TiO 2 , and Nd/TiO 2 (Figure 3) [18,20].…”

The Role of Fluorine in F-La/TiO2 Photocatalysts on Photocatalytic Decomposition of Methanol-Water Solution

“…Textural, structural, optical, and electronic properties of all photocatalysts were characterized in detail by nitrogen physisorption [22,23], powder X-ray diffraction (XRD) [22,23], X-ray fluorescence (XRF) [20], diffuse reflectance UV-vis spectroscopy (DRS UV-Vis) [22,24], X-ray photoelectron spectroscopy (XPS) [22], and photoelectrochemical measurements [23] (see Supplementary Materials). Chemical components and the binding energies of CdS/CN were analyzed by XPS (Thermo Scientific ESCALAB 250Xi A1440 system, Waltham, MA, USA).…”

“…The photocatalytic decomposition of the methanol-water solution was carried out in a batch photoreactor with a 8 W Hg lamp (λ = 365 nm, see Supplementary Materials) [22].…”