• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.163-172
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• 2018

In this study, selective catalytic reductions (SCR) of NO commercial catalysts were used to investigate the effect of ammonia gasification from urea solution. The effects of catalytic chemical composition on the reaction temperature and space velocity were studied. $V_2O_5/TiO_2$ catalysts, which are widely used as SCR catalysts for removal of nitrogen oxides, have better ammonia formation compare to $TiO_2$ and $WO_3-V_2O_5/TiO_2$ catalysts. The $TiO_2$ catalyst not supporting the active metal was not affected by the space velocity as compared with the catalyst supporting $V_2O_5$ or $WO_3-V_2O_5$. The active metal supported catalysts decreased in the ammonia formation as the space velocity increased.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.599-606
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• 2021

In this study, an experiment and a reaction characteristic study were conducted to enhance the reaction activity of V₂O₅/WO₃/TiO₂ at 300 ℃ or less by adding selenium to the support, in a selective catalytic reduction method using ammonia as a reducing agent to remove nitrogen oxides. Se-TiO₂ and TiO₂ were synthesized using the sol-gel method, and used as a support when preparing V₂O₅/WO₃/TiO₂ and V₂O₅/WO₃/Se-TiO₂ catalysts. The reaction activity of our catalyst was compared with that of a commercial catalyst. The denitration efficiency of the catalyst using TiO₂ prepared by the sol-gel method was lower than that of the catalyst prepared using commercial TiO₂, but was improved by the addition of selenium. Thus, the effect of selenium addition on the catalyst structure was analyzed using BET, XRD, Raman, H₂-TPR, and FT-IR measurements and the effect of the increase in specific surface area by selenium addition and the formation of monomer and complex vanadium species on reaction characteristics were confirmed.

• Transactions of the Korean hydrogen and new energy society
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• v.3 no.2
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• pp.25-33
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• 1992

With the aim to obtain $TiO_2$ films with an increased photorespones and absorbance in the visible region of the solar spectrum, the direct oxidation of titanium alloys were performed. In this study, $Ti-Ga_2O_3$ alloy was prepared by mixing, pressing and arc melting of appropriate amounts of titanium and $Ga_2O_3$ powder. Electrochemical measurements were performed in three electrode cell using electrolyte of 1M NaOH solution. The oxide films on $Ti-Ga_2O_3$ alloy was composed of $Ti_2O$, TiO, $TiO_2$, $Ga_2TiO_5$. The free energy efficiency (${\eta}e$) of $Ti-Ga_2O_3$ oxide films had 0.8~1.3 % and were increased with the increase of $Ga_2O_3$ content up to 10wt %. The onset potential ($V_{on}$) had -0.8V~0.9V ranges and were shifted to anodic direction with the increase of $Ga_2O_3$ content. The spectral response of Ti-$Ga_2O_3$ oxides were similar to the response of the $TiO_2$ and their $E_g$ were observed to 2.90~3.0eV. Variations of onset potential($V_{on}$) associated with electrolyte pH were -59mV/pH. This probably reflects the nature of the bonding of $OH^-$ ion to the $TiO_2$ surface, a common phenomena in the transition-metal oxides.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.161-163
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• 2008

$TiO_2-V_2O_5$ sol was fabricated using sol-gel method and $TiO_2-V_2O_5$, thin films were fabricated using dip-coating method. $V_2O_5$ sol was added 0.01mole, 0.03mole, 0.05mole into $TiO_2$ sol. Capacitance of thin films decreased with increasing $V_2O_5$ additive and it increased largest at 0.01mole. Because adsorption time and desorption time of thin films was about 2 minutes 40 seconds and about 3 minutes 40 seconds respectively, adsorption time was faster about 1 minutes than desorption time.

• Journal of the Korean institute of surface engineering
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• v.36 no.4
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• pp.329-333
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• 2003

The high-temperature oxidation behavior of Ti39Al-10V alloy that consisted primarily of $\beta$-Ti, ${\gamma}$-TiAl, and $\alpha_2$ $-Ti_3$Al phases was studied. The relatively thick and porous oxide scales formed consisted primarily of an outermost, thin TiO$_2$ layer, and an outer, thin $Al_2$$O_3$-rich layer, and an inner, very thick (TiO$_2$, $Al_2$$O_3$) mixed layer. Vanadium was present uniformly throughout the oxide scale. The formation and subsequent evaporation of V-oxides such as VO, $VO_2$, and $V_2$O$_{5}$ deteriorated oxidation resistance and scale adherence of the TiAl alloy significantly.y.

• Journal of the Korean Ceramic Society
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• v.22 no.3
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• pp.19-24
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• 1985

The phtoelectrochemical porperties of $Nb_2O_5$, $Sb_2O_3$ and $V_2O_5$ doped and pure $SrTiO_3$ ceramic electodes were investigated. Shapes of I-V and I-λ characteristics of the pure $SrTiO_3$ ceramic electrode are similar to those of SrTiO3 single crystal electorde ; the anodic current strats at -0.9V (vs. Ag/AgCI) in 1 N-NaOH aqueous solution and the photoresponse appears at a wavelength of about 390nm and the quantum efficiency is about 3.5% at wavelength of 390nm under 0.5V vs. Ag/AgCl. Photocurrents of $Nb_2O_5$, $Sb_2O_3$ and $V_2O_5$ doped electrodes and $V_2O_5$ doped ceramic electrode appears at wavelength of 390nm and 500nm respectively.

• Journal of Environmental Science International
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• v.15 no.4
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• pp.333-340
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• 2006

A (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ catalyst were prepared by co-precipitation method and used for low-temperature selective catalytic reduction (SCR) of $NO_x$ with ammonia in the presence of oxygen. The properties of the catalysts were studied by X-ray diffraction (XRD), temperature programmed reduction (TPR) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS). The experimental results showed that (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ catalyst yielded 81% NO conversion at temperature as low as $150^{\circ}C$ and a space velocity of $2,400\;h^{-1}$. Crystalline phase of $Mn_{2}O_3$ was present at ${\ge}\;15%$ Mn on $V_{2}O_{5}/TiO_{2}$. XRD confirmed the presence of manganese oxide ($Mn_{2}O_{3}$) at $2{\theta}=32.978^{\circ}(222)$. The XRD patterns presented of (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ did not show intense or sharp peaks for manganese oxides and vanadia oxides. The TPR profiles of (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ catalyst showed main reduction peat of a maximum at $595^{\circ}C$.

• Current Photovoltaic Research
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• v.3 no.3
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• pp.71-74
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• 2015

Soluble polyaniline was synthesized by attaching titanium isoproxide ($Ti(OPr)_4$) to the amine group of the aniline. Approximately 1 to 1 molar ratio of aniline and $Ti(OPr)_4$ was mixed and polymerized with ammonium persulfate. The FTIR result showed clear difference between $TiO_2$-aniline composite ($TiO_2An$) and $TiO_2$-polyaniline composite ($TiO_2PAn$). Although the $TiO_2An$ had negligible UV-visible absorption, the $TiO_2PAn$ showed strong absorption in the UV-visible region. Photoluminescence (PL) peaks of $TiO_2An$ were shifted toward red with the reduction of the excitation energy, which could be due to the multiple emission centers. The luminescence peak shift stopped at 501 nm. The PL spectra of $TiO_2PAn$ exhibited three emission peaks at 2.88 eV (430 nm), 2.48 eV (501 nm) and 2.22 eV (558 nm). The new emission center (2.22 eV) was observed after polymerization. Field emission scanning electron microscope image showed crack-free composite film.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.284-291
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• 1997

The electrode characteristics of two kinds of metal hydride electrodes using V-Ti (V-rich) based alloy were studied, in which one electrode was prepared by sintering the mixture of V-Ti alloy and Ni powders by a rapid thermal annealing technique and the other one was prepared using V-Ti-Ni ternary alloy, The discharge capacities of all electrodes during the charge-discharge cycling were completely deteriorated within 10 cycles. It appeared that the deterioration of the electrodes was caused by the dissolution of V in the near-surface region into the electrolyte and the formation of $TiO_2$ layer on the alloy particle surface. This degradation mechanism was supported by the facts that V is main hydride forming element and $TiO_2$ has very low electrical conductivity and hydrogen diffusivity.

• Journal of the Korean Electrochemical Society
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• v.17 no.1
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• pp.13-17
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• 2014

The $TiO_2$ nanotube/Ti electrode are used as an anode in thin-film lithium microbatteries is known to have high oxidation-reduction potential of 1.8 V (vs. $Li/Li^+$). It can prevent from dendrite growth of lithium during charging. The $TiO_2$ nanotube/Ti electrode was prepared by anodizing at constant voltages for thin-film lithium microbatteries. The capacities of $TiO_2$ nanotube/Ti anode prepared by anodizing at 10 V, 20 V and 30 V were observed to be $23.9{\mu}Ah\;cm^{-2}$, $43.1{\mu}Ah\;cm^{-2}$ and $74.0{\mu}Ah\;cm^{-2}$. We identified it was found that the capacity of $TiO_2$ nanotube/Ti increases with increasing anodizing voltage and the anatase structure of $TiO_2$ nanotube/Ti compared with amorphous structure has batter cycle performance than amorphous $TiO_2$ nanotube/Ti.