• Ceramist
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• v.22 no.3
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• pp.230-242
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• 2019

Functional ceramics are widely utilized in a variety of application fields such as structural materials, sensors, energy devices, purification filter and etc due to their high strength, stability and chemical activity. With the breakthrough development of nanotechnology, many researchers have studied new types of nanomaterials including nanoparticle, nanorod, nanowire and nanoplate to realize high-performance ceramics. Especially several groups have focused on the 3D nanostructured ceramics because of their large surface area, efficient load transfer, ultra-fast ion diffusion and superior electrical (or thermal) conductivity. In this review, we introduce the reported fabrication strategies of the 3D nanostructured and functional ceramics, also summarized the 3D nanostructured ceramic based high-performance applications containing photocatalysts, structural materials, energy harvesting and storage devices.

• Journal of the Korean Ceramic Society
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• v.47 no.1
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• pp.47-53
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• 2010

Ceramics with perovskite-type structure are interesting functional materials for several energy conversion processes due to their flexible structure and a variety of properties. Prominent examples are electrode materials in fuel cells and batteries, thermoelectric converters, piezoelectrics, and photocatalysts. The very attractive physical-chemical properties of perovskite-type phases can be modified in a controlled way by changing the composition and crystallographic structure in tailor-made soft chemistry synthesis processes. Improved thermoelectric materials such as cobaltates with p-type conductivity and n-type manganates are developed by following theoretical predictions and tested to be applied in oxidic thermoelectric converters.

• Rapid Communication in Photoscience
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• v.2 no.1
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• pp.9-17
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• 2013

Visible light-sensitive $TiO_2$ and ZnO nanostructure materials have attracted great attention as the promising material for solar energy conversion systems such as photocatalysts for water splitting and environmental purification as well as nano-biosensors. Success of their applications relies on how to control their surface state behaviors related to the exciton dynamics and optoelectronic properties. In this paper, we briefly review some recent works on single nanoparticle photoluminescence (PL) technique and its application to observation of their surface state behaviors which are raveled by the conventional ensemble-averaged spectroscopic techniques. This review provides an opportunity to understand the temporal and spatial heterogeneities within an individual nanostructure, allowing for the potential use of single-nanoparticle approaches in studies of their photoenergy conversion and nano-scale optical biosensing.

• Journal of environmental and Sanitary engineering
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• v.20 no.4 s.58
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• pp.51-58
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• 2005

Photocatalytic degradation using $TiO_2$ Particles suspended in a reactor was experimentally performed to degrade the formaldehyde of indoor pollutants. Exponential increase of degradation appears to prove light availability due to the scattering of W light by particles themselves. Comparative removal studies of formaldehyde were done in both cases of dipping and spraying immobilized techniques of $TiO_2$ Particles suspended in solution. Experiments were performed under several different experimental conditions such as initial concentration of formaldehyde, UV intensity and concentration of photocatalysts. Optimal conditions to degrade formaldehyde were obtained under the conditions of $30\;mg/cm^2$ concentration of catalyst and UV intensity of 30 Watt at the distance of 30 cm using immobilized technique by dipping coating.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.5
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• pp.196-203
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• 2007

We have studied a method for the preparation of hybrid $carbon/TiO_2$ complexes involving pitch coating, pitch binding and the penetration of titanium n-butoxide(TNB) solution with porous carbon. The photocatalysts were investigated with surface textural properties and SEM morphology, structural crystallinity and elemental identification between porous carbon and $TiO_2$, and dye decomposition performance. For the all $carbon/TiO_2$ complexes prepared by some kinds of different methods, the excellent photocatalytic effect for dye degradation should be attributed to the both effects between photo-decomposition of the supported $TiO_2$ and adsorptivity of the porous carbons.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.155-160
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• 2012

This paper reported a simple deposition-precipitation method, introducing the metal (Ni, Ag and Sn) and $Na_2S{\cdot}5H_2O$ to preparedispersion metal sulfide nanoparticles on the surface of the Multi-walled carbon nanotube for synthesis of CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composite photocatalysts. The characterization of the prepared CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composites was performed by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis and BET analysis. Furthermore, the MB degradation rate constant for CNT-SnS composite was $5.68{\times}10^{-3}$ under visible light irradiation, which was much higher than the corresponding values for other samples. The detailed formation and photocatalytic mechanism are also provided here.

• Transactions of the Korean hydrogen and new energy society
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• v.1 no.1
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• pp.9-14
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• 1989

Mixed photocatalyst containing cadmium sulfide and zinc sulfide was prepared on silica gel powder and Nafion film. Photo-irradiation of aqueous mixture containing the photocatalysis generated hydrogen by water cleavage reaction. Use of sodium sulfide as sacrificial reagent help the photo-reaction. Evolution of the hydrogen was measured by gas chromatographic analysis. Composition of the catalyst was determined by atomic absorption spectrophotometer. 0.2 mL of of hydrogen was generated per hour. The maximun catalytic activity was obtained after 8-12 hours later. Hydrogen generation efficiency by the two different catalytic system was compared and showed that the Nafion-based catalyst is more efficient than the silicagel-based catalyst for the photoreaction.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.70-70
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• 2011

본 논문에서는 에너지 절감형 선박평형수 처리장치를 개발하기 위하여 $TiO_2$ 광촉매와 자외선 램프를 적용한 선박평형수 처리장치에 대하여 기술하였다. 제작된 처리장치의 정격 출력과 처리용량은 각각 2.16 kW 및 $100m^3/h$이다. 처리장치의 살균효율은 플랑크톤을 사용하여 IMO 규정에 따라 평가하였다. 실험결과로부터 시제작 선박평형수 처리장치의 살균효율은 동물성 플랑크톤에서 99.7 %, 식물성 플랑크톤에서 98.84 %로 나타났다.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.577-582
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• 2004

The photocatalytic degradation of atrazine and PCP, a endocrine disruptors, has been investigated over $TiO_2$ photocatalysts under ultraviolet (UV) light irradiation. The effect of operational parameters, i.e., pH, light intensity and persulphate concentration on the degradation rate of aqueous solution of atrazine and PCP has been examined. The results presented in this work demonstrate that, as pH and the light intensity increased, the photocatalytic reaction rates were enhanced. Individual use of $TiO_2$-persulphate was far more effective than using only $TiO_2$ in atrazine and PCP removal. Based on the overall experimental results, the photocatalytic oxidation of atrazine and PCP with the coated $TiO_2$ photocatalyst is found to be very effective under the operational conditions delineated in this study.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.40-47
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• 2002

Because UV wavelength lights can activate photocatalysts, plasma is used as a light source of a photocatalytic reactor. Even though plasma has good intensity for photo reaction, substrate of catalyst coating was limited by the geometry of plasma generator. Usually bead type substrate was used for a pack bed type reactor. Honeycomb monolith type substrate was used with UV lamps instead plasma, due to the light penetration the honeycomb monolith length was too short to show good activity In this study a photocatalytic reactor, which is using a honeycomb monolith substrate, was investigated with plasma as an activation light source. As a parametric study the effects of 1311owing factors on plasma generation and power consumption are examined; supply voltage, substrate length, environment condition, catalyst loading and ratio. Using the test results, the practicability test was done with simulated synthetic gases representing bad smells and automotive exhaust gases.