Influence of transition metal doping on the structural, optical, and magnetic properties of TiO2 films deposited on Si substrates by a sol-gel process.
TL;DR: It is found that the magnetizations of the TM-doped TiO2 films decrease with increasing dopant content, which is related to electric disorder due to the ART.
Abstract: Transition metal (TM)-doped TiO2 films (TM = Co, Ni, and Fe) were deposited on Si(100) substrates by a sol–gel method. With the same dopant content, Co dopants catalyze the anatase-to-rutile transformation (ART) more obviously than Ni and Fe doping. This is attributed to the different strain energy induced by the different dopants. The optical properties of TM-doped TiO2 films were studied with spectroscopic ellipsometry data. With increasing dopant content, the optical band gap (EOBG) shifts to lower energy. With the same dopant content, the EOBG of Co-doped TiO2 film is the smallest and that of Fe-doped TiO2 film is the largest. The results are related to electric disorder due to the ART. Ferromagnetic behaviors were clearly observed for TM-doped TiO2 films except the undoped TiO2 film which is weakly magnetic. Additionally, it is found that the magnetizations of the TM-doped TiO2 films decrease with increasing dopant content.
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TL;DR: Among the samples, Fe-1wt% doped TiO2 nanoparticles showed the highest photocatalytic decolorization of RR198 under visible light irradiation.
136 citations
TL;DR: In this article, structural, magnetic and ferroelectric properties of Ni doped barium titanate were investigated using solid state sintering technique and it was revealed from structural studies that the phase transformation from tetragonal to hexagonal phase is strongly influenced by Ni doping concentration.
92 citations
TL;DR: In this paper, undoped and Ni-doped TiO 2 ( x Ni ǫ = 0.00, 0.50, 1.00 and 2.50 ) thin films fabricated on glass substrates by using a combination of solid-state reaction and dip coating techniques.
67 citations
11 Jan 2018
TL;DR: The enhanced rate capability and cycling stability were attributed to the enlargement of the NaO2 slab in the crystal structure because of Ti doping, which promoted Na-ion diffusion and prevented the phase transition from the P2 to the OP4/″Z″ structure.
Abstract: In this study, we developed a doping technology capable of improving the electrochemical performance, including the rate capability and cycling stability, of P2-type Na0.67Fe0.5Mn0.5O2 as a cathode material for sodium-ion batteries. Our approach involved using titanium as a doping element to partly substitute either Fe or Mn in Na0.67Fe0.5Mn0.5O2. The Ti-substituted Na0.67Fe0.5Mn0.5O2 shows superior electrochemical properties compared to the pristine sample. We investigated the changes in the crystal structure, surface chemistry, and particle morphology caused by Ti doping and correlated these changes to the improved performance. The enhanced rate capability and cycling stability were attributed to the enlargement of the NaO2 slab in the crystal structure because of Ti doping. This promoted Na-ion diffusion and prevented the phase transition from the P2 to the OP4/″Z″ structure.
62 citations
TL;DR: In this paper, the Fe-Ni co-doped and Ag deposited anatase TiO2 (Fe-Ni/Ag/TiO2) nanocomposites were successfully prepared by a simple one-pot solvothermal approach.
55 citations
References
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TL;DR: In this paper, the influence of Co doping on the anatase-to-rutile transformation of TiO 2 thin films was investigated by Raman spectroscopy and X-ray diffraction.
Abstract: The influences of Co doping on the anatase-to-rutile transformation of TiO 2 thin films have been investigated by Raman spectroscopy and X-ray diffraction. Raman spectra and XRD patterns for the samples of various Co concentrations present a clear evolution of TiO 2 with different anatase-to-rutile ratios. The fraction of rutile phase increases gradually with increasing Co contents. When Co content exceeds 7 mol%, anatase phase is not detected in the samples. The results may be related to the oxygen vacancies, which are introduced by Co doping. According to the Adachi model, optical constant was extracted by spectroscopic ellipsometry. It is found that the refractive index n increases with increasing Co content from 2.29 to 2.4, and that the optical band gap decreases and varies with increment of Co content between 3.6 and 3.38 eV. This may be related to the changes in film density and band gap tailed due to the Co doping.
9 citations
"Influence of transition metal dopin..." refers methods in this paper
...In our previous studies, the optical constants of some materials have been successfully obtained using the SE technique [42,43]....
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...ε(Ε) = ε∞ + {A0[2 − (1 + χ0) 1/2 − (1 − χ0) ]}/(EOBG χ0 (2)), where, E is the incident photon energy, ε∞ is the high-frequency dielectric constant, χ0 = (E + iΓ), EOBG is the optical gap energy, and A0 and Γ are the strength and broadening parameters of the EOBG transition, respectively [42,44]....
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29 Mar 2004
TL;DR: In this paper, the formation behavior and photo-oxidation abilities of nanostructured TiO2 powders were investigated through a direct crystallization from aqueous TiOCl2 solutions containing various metal-chlorides at 100°C.
Abstract: Formation behavior and photo-oxidation abilities of nanostructured TiO2 powders were investigated through a direct
crystallization from aqueous TiOCl2 solutions containing various metal-chlorides at 100°C. The obtained TiO2 powders without any additives and those added with Ni2+, Fe3+ and Nb5+ ions, which have a similar positive ionic radius to Ti4+, were mainly crystallized with rutile phase, whereas those added with Al3+ and Zr4+ ions, which have a quite different positive ionic radius, were mainly crystallized with anatase phase. On the other hand, the secondary particles in the TiO2 powder consisted of acicular and spherical primary particles corresponding to rutile and anatase phases, respectively. From these results, it seems that the positive ionic radius of the additives would affect phase formation as well as morphology of TiO2 precipitates. Among the TiO2 powders prepared, Ni-added powder, which consisted mainly of rutile phase with a small amount of anatase phase, showed excellent photocatalytic ability in decomposition of 4-chlorophenol.
3 citations
"Influence of transition metal dopin..." refers result in this paper
...Thus, the rutile content of Co- or Ni-doped TiO2 films is more than that of the Fe-doped TiO2 films....
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...Figure 2 shows a high-resolution XPS spectrum of the Ti 2p region for Ni-doped TiO2 thin films, respectively....
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...The M values of doped samples decrease with increasing metal element contents, which is similar to the Ni-doped TiO2 powders [21] and Fe-doped TiO2 films [52]....
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...Tian J, Gao H, Deng H, Sun L, Kong H, Yang P, Chu J: Structural, magnetic and optical properties of Ni-doped TiO2 thin films deposited on silicon (100) substrates by sol–gel process....
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...These results indicate that the addition of dopant catalyzes the anatase-to-rutile transformation (ART), which are similar to those of the Co-doped [23,33], Ni-doped [34,35], and Fe-doped [36-39] TiO2 powders....
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