scholarly journals Characterization, X-ray Absorption Spectroscopic Analysis and Photocatalytic Activity of Co/Zn Co-Doped TiO2 Nanoparticles Synthesized by One-Step Sonochemical Process

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1254
Author(s):  
Wanichaya Mekprasart ◽  
Sorapong Pavasupree ◽  
C. K. Jayasankar ◽  
Balaji Rao Ravuri ◽  
Chakkaphan Wattanawikkam ◽  
...  

A novel one-step preparation of sonochemical method was applied to synthesize Co/Zn co-doped TiO2 nanoparticles using a sonicator of 750 W, 20 kHz for 30 min at room temperature. The formation of the anatase TiO2 phase for all as-prepared samples was observed from XRD results with a crystalline size in nanoscale. The use of ultrasound allowed for the successful doping of both Co and Zn into the TiO2 lattice, which was confirmed by Synchrotron light including X-ray near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy. Ti K-edge, Co K-edge, and Zn K-edge XANES spectra exhibited the dominating +4, +2, and +2 valence state of Ti, Co, and Zn in as-prepared samples, respectively. A detailed XANES and EXAFS data analysis give strong evidence that the Co/Zn dopants partially replace the Ti atom of the TiO2 host. The Co/Zn co-doping extends the light absorption of the host to the visible region and restricts the e+/h+ recombination. The photocatalytic activity of samples was tested for degradation of Rhodamine B dye solution under visible light irradiation. The as-synthesized of the co-doped catalyst was presented as highly efficient, with 2.5 and 5 times dye degradation compared with single-doped and bare TiO2.

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 235
Author(s):  
Hayette Benkhennouche-Bouchene ◽  
Julien G. Mahy ◽  
Cédric Wolfs ◽  
Bénédicte Vertruyen ◽  
Dirk Poelman ◽  
...  

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.


2018 ◽  
Vol 71 (5) ◽  
pp. 315 ◽  
Author(s):  
Xiongbo Dong ◽  
Zhiming Sun ◽  
Xiangwei Zhang ◽  
Xue Li ◽  
Shuilin Zheng

A C/N co-doped TiO2/diatomite composite with exposed (001) facet was prepared through a facile sol–gel method using tetrabutyl titanate as a titanium precursor and hexamethylenetetramine as C/N dopant. The as-prepared photocatalyst composites were characterised by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS), photoluminescence spectroscopy (PL), as well as X-ray photoelectron spectroscopy (XPS). The TiO2 nanoparticles were immobilised and uniformly distributed on the surface of diatomite with a smaller grain size compared with pure TiO2. In addition, compared with pure TiO2 and the undoped TiO2/diatomite composite, the photocatalytic activity of the C/N co-doped TiO2/diatomite composite under solar light illumination was obviously enhanced. Results indicate that the introduction of a C/N dopant can effectively promote the growth of the highly active anatase (001) facet of TiO2. On the other hand, the N impurity was doped into the interstitial spaces of the TiO2 lattice, which accelerated the charge transfer and hindered the recombination of photogenerated electron–hole pairs. The results show that the as-prepared composite exhibited promising applications in dye wastewater degradation owing to its outstanding reusability and cost-effectiveness.


Author(s):  
Chelaramani K. ◽  
Varshney R. ◽  
Bhardwaj A.

The TiO2 and Ag and Zn doped TiO2 nanoparticles were synthesized by sol-gel method.The sol-gel method is one of the versatile method to prepare doped and co-doped nanoparticles. sol gel method has emerged as simpler and better option than physical and chemical procedures as it is fast, clean and eco-friendly alternative that does not involve any costly instruments .Synthesis of doped and co-doped nanoparticles having good photocatalytic activity have great potential for the degradation of dye. We have tried to develop new effective antimicrobial reagents with good photocatalytic activities which are not resistant to disease causing microbes.


2010 ◽  
Vol 25 (4) ◽  
pp. 711-717 ◽  
Author(s):  
Wei-Qiang Han ◽  
Dong Su ◽  
Michael Murphy ◽  
Matthew Ward ◽  
Tsun-Kong Sham ◽  
...  

PtPd@Pt core-shell ultrathin nanowires were prepared using a one-step phase-transfer approach. The diameters of the nanowires range from 2 to 3 nm, and their lengths are up to hundreds of nanometers. Line scanning electron energy loss spectra showed that PtPd bimetallic nanowires have a core-shell structure, with a PtPd alloy core and a Pt monolayer shell. X-ray absorption near edge structure (XANES) spectra reveal that a strong Pt-Pd interaction exists in this nanowire system in that there is PtPd alloying and/or interfacial interaction. Extended x-ray absorption fine structures (EXAFS) further confirms the PtPd@Pt core-shell structure. The bimetallic nanowires were determined to be face-centered cubic structures. The long-chain organic molecules of n-dodecyl trimethylammonium bromide and octadecylamine, used as surfactants during synthesis, were clearly observed using aberration-corrected TEM operated at 80 KV. The interaction of Pt and surfactants was also revealed by EXAFS.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Xiaojiang Nie ◽  
junkun Wang ◽  
Wenchao Duan ◽  
zilong zhao ◽  
Liang Li ◽  
...  

The crystallization of amorphous TiO2 nanotubes which prepared by anodic oxidation was crystallized by water-assisted at low temperature. The crystalline phase and morphology of TiO2 nanotubes were observed by X-ray...


2018 ◽  
Vol 2017 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Desireé M. de los Santos ◽  
Sara Chahid ◽  
Rodrigo Alcántara ◽  
Javier Navas ◽  
Teresa Aguilar ◽  
...  

Abstract Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO2 was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO2 and x%MoS2/Cu/TiO2 nanoparticles were prepared, where x is the theoretical quantity of MoS2 added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO2 structure was doped with the Mo6+ and Cu2+ ions in the position of the Ti4+. The x%MoS2/Cu/TiO2 samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO2 sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS2/Cu/TiO2) there were significant increases of up to 93% in the photocatalytic activity.


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