• Journal of Industrial Technology
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• v.24 no.B
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• pp.133-138
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• 2004

The photodegradation of phenol and toluene with the $TiO_2$-coated polyethylene (PE) particles were investigated in the slurry type photocatalytic reactor, changing the $TiO_2$ particle sizes, initial phenol and toluene concentrations, and the oxygen flow rate. The nano-sized $TiO_2$ photocatalyst particles were prepared by the diffusion flame reactor and they were coated onto PE particles by using the hybridization system for the efficient recollection of $TiO_2$-coated particles after photodegradation experiments. The degradation efficiencies of phenol and toluene with the $TiO_2$-coated PE particles were more than 90% after photodegradation of 80 minutes for most cases. The efficiencies of photodegradation with the $TiO_2$-coated PE particles were found to be lower than those by the pure $TiO_2$ particles by 50%, because of the decrease in specific surface area of $TiO_2$ particles in PE particles.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.5
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• pp.404-409
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• 2009

The present works were performed that titanium foil was anodized in various dilution ratios of seawater and distilled water with 10V external voltage applied, then annealed at $450^{\circ}C$ to obtain $TiO_2$ on the Ti substrate. The prepared samples were characterized by instruments (XRD, SEM, and photocurrent) and used to investigate rate of hydrogen production in photoelectrochemical cell as well as Cr(VI) reduction. As the results of experiments, the anodized $TiO_2$ in seawater electrolytes, which are ranged from 15 to 50 times dilution of seawater, was showed a relatively higher hydrogen production (ca. 97~110 umol/hr-$cm^2$) and Cr(VI) reduction (ca. 95% reduction).

• Journal of Environmental Science International
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• v.16 no.4
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• pp.433-440
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• 2007

The photodegradation and by-products of the gaseous toluene with $TiO_2$ (P25) and short-wavelength UV ($UV_{254+185nm}$) radiation were studied. The toluene was decomposed and mineralized efficiently owed to the synergistic effect of photochemical oxidation in the gas phase and photocatalytic oxidation on the $TiO_2$ surface. The toluene by the $UV_{254+185nm}$ photoirradiated $TiO_2$ were mainly mineralized $CO_2$ and CO, but some water-soluble organic intermediates were also formed under severe reaction conditions. The ozone and secondary organic aerosol were produced as undesirable by-products. It was found that wet scrubber was useful as post-treatment to remove water-soluble organic intermediates. Excess ozone could be easily removed by means of a $MnO_2$ ozone-decomposition catalyst. It was also observed that the $MnO_2$ catalyst could decompose organic compounds by using oxygen reactive species formed in process of ozone decomposition.

• Carbon letters
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• v.9 no.2
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• pp.131-136
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• 2008

In order to investigate the effect of doping C, N, B and F elements on $TiO_2$ for reducing the band gap, the heat treatment of $TiO_2$ was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F doped anatase $TiO_2$ was confirmed. According to the increase of temperature during treatment, the particle size was increased due to aggregation of $TiO_2$ with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye under solar light, the degradation of acridine orange and methylene blue was conducted. The degradation of dyes was carried out successfully under solar light indicating the effect of doping elements (B, C, N and F) on $TiO_2$ for reducing the band gap effectively.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.169-176
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• 2010

The Fe-treated CNT/$TiO_2$ photocatalysts mixed with anatase and rutile phase have been developed for the decomposition of non-biodegradable different organic dyes like methylene blue (MB), rhodamine B (Rh.B), and methyl orange (MO) in two conditions as ultraviolet and visible light respectively. The results indicate that all the Fe-CNT/$TiO_2$ composites proved to be more efficient photocatalysts since degradation of MB at higher reaction rates, tthe decomposition rate of different dyes increases with an increase of $Fe^{3+}$ concentration in composites the highest rate of decomposition of different dyes was noted under UV irradiation. These results can indicate that the large CNT network is facilitate the electron transfer and strongly adsorb dye molecules on the texted photocatalysts, iron is reactive in the photo-Fenton process resulting in high production of OH radicals and also high activity of the photocatalyst. And Fe particles can generate more photoinduced electrons to conduction band of $TiO_2$ under visible light irradiation. The composites of Fe-CNT/$TiO_2$ photocatalysts synthesized by a sol-gel method were characterized by BET, TEM, SEM, XRD and EDX.

• Journal of the Korean Ceramic Society
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• v.51 no.1
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• pp.1-6
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• 2014

Here we report improved photo-catalytic effect of $Ag_2S$ under visible light using carbon nano-tubes (CNT) modified with $Ag_2S$ nanoparticles. The optical properties, structural properties and compositional analysis, as well as the photo-electrochemical properties of the prepared composites were investigated. It was found that the photocurrent density, and the photo-catalytic effect, was increased by modification of CNT in this way. Compared with the separate effects of $Ag_2S$ and CNT nanoparticles, the photocatalytic effect of CNT-modified-with-$Ag_2S$ composites, increased significantly due to a synergistic effect between the CNT and the $Ag_2S$ nanoparticles.

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.43-46
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• 2000

$H_4Nb_6/O_{17}$/CdS nanocomposites which intercalated CdS particles, less than 0.8nm thickness, in the interlayer of $H_4Nb_6/O_{17}$ were prepared by the successive ion exchange reactions of $H_4Nb_6/O_{17}$ with $Cd^{2+}$ and $C_3H_7NH_3_+$, followed by the reaction with $H_2S$ gas. $H_4Nb_6/O_{17}$/CdS photocatalytically reduced $NO_3$￣ to $NO_2$￣ and $NH_3$in the presence of sacrificial hole acceptor such as methanol under visible light irradiation (wavelength>400nm), although unsupported CdS showed no noticeable photocatalytic activity for $NO_3$￣ reduction. The catalytic activity of $H_4Nb_6/O_{17}$/CdS greatly enhanced with co-doping of Pt particles in the interlayer.

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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• pp.415-422
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• 2005

The photocatalytic decolorization of Reactive Red 2B(RR2B) was studied using immobilized photocatalyst/UV System. Two pairs of 20 W UV-B and UV-C lamps were employed as the light source. Immobilization of $TiO_2$ was carried out using sponge (as the photocatalyst body) and silicone sealant(as the binder). The effects of parameters such as the thickness, pore size of sponge photocatalyst and attached material on the reactor bottom were investigated. The results showed that the optimum thickness of sponge photocatalyst was 1 cm. Decolorization of reactor which had the bottom coated $TiO_2$ was higher than that of reactor attached aluminum plate. Decolorization of photocatalyst with large pore size(mean pore size, 3.8 mm) was higher than that of the small(mean pore size, 1.75 mm). Initial decolorization of RR2B could be descrived using the Langmuir-Hinshelwood(L-H) model and gave constant values of $0.55mg/l{\cdot}min(k)\;and\;2.65{\times}10^{-2}l/mg(K)$, respectively.

• Rapid Communication in Photoscience
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• v.3 no.2
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• pp.35-37
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• 2014

PEC (photoelectrochemical) water splitting for $O_2/H_2$ production is one of the promising but difficult way to utilize solar energy. Among photocatalytic materials for PEC water oxidation, $BiVO_4$ (Eg = 2.4 eV) has been recently intensively studied since it has various advantageous properties. But its maximum efficiency has not been realized owing to kinetic factors - slow water oxidation at surface & insufficient stability. These problems can be simultaneously solved by application of oxygen evolution catalyst (OEC) such as $CoO_x$, Co-Pi, $IrO_x$ etc. Herein we report the first successful application of $NiFeO_x$ OEC on $BiVO_4$, showing good performance compared to other effective OEC applied on $BiVO_4$ under basic conditions. The enhanced activity of OEC loaded $BiVO_4$ has been supported by the surface charge separation efficiency and electrochemical impedance studies.

• Rapid Communication in Photoscience
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• v.2 no.2
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• pp.64-66
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• 2013

Photoreduction of $CO_2$ into hydrocarbon fuels on the surface of photocatalyst is one of the breakthroughs in the field of photocatalysis. At present various approaches have been investigated with the aim of increasing the $CO_2$ conversion efficiency. The reactor for photoconversion of $CO_2$ plays a vital role in experimental setup. In this work an attempt was made to testify a newly designed the photoreactor for conversion of $CO_2$ into useful products. The photoreactor was specifically designed for simple operation bearing features of temperature and pressure control. The reactor has been tested successively with the standard titania, Degussa P25 yielding methane with moderate production rate of 30.8 $ppm{\cdot}g^{-1}{\cdot}h^{-1}$ under UV lamp with 365 nm wavelength. The methane yield obtained is comparable to the values reported in literature. Thus we anticipate that this experimental setup equipped with newly designed photoreactor can yield competitive amounts of fuels from $CO_2$ photoredcution via 365 nm UV light illumination on various photocatalysts.