• Proceeding of EDISON Challenge
• /
• 2015.03a
• /
• pp.367-370
• /
• 2015

Monolayer transition metal dicalcogenide (TMDC) materials are currently attracting extensive attention due to their distinctive electronic, transport, and optical properties. For example, monolayer $MoS_2$ exhibits a direct band gap in the visible frequency range, which makes it an attractive candidate for the photocatalytic water splitting. For the photoelectrochemical water splitting, the appropriate band edge positions that overlap with the water redox potential are necessary. Similarly, appropriate band level alignments will be crucial for the light emitting diode and photovoltaic applications utlizing heterojunctions between two TMDC materials. Carrying out first-principles calculations, we here investigate how the band edges of $MoS_2$ can be adjusted by surface ligand functionalization. This study will provide useful information for the realization of ligand-based band engineering of monolayer $MoS_2$ for various electronic, energy, and bio device applications.

• Transactions of the Korean hydrogen and new energy society
• /
• v.18 no.1
• /
• pp.95-108
• /
• 2007

There are several methods for the hydrogen production such as steam reforming of natural gas, photocatalytic method, biological method, electrolysis and thermochemical method, etc. These days it has been widely studying for the hydrogen production method having low hydrogen production cost and high efficiency. In this paper, patents in the hydrogen production by water electrolysis were gathered and analyzed. The search range was limited in the open patents of USA(US), European Union(EP), Japan(JP), and Korea(KR) from 1996 to 2005. Patents were gathered by using key-words searching and filtered by filtering criteria. The trends of the patents was analyzed by the years, countries, companies, and technologies.

• Ceramist
• /
• v.20 no.4
• /
• pp.55-73
• /
• 2017

As one of the most versatile semiconductors, zinc oxide (ZnO) with one-dimensional (1-D) nanostructures has been significantly developed for the application of ultraviolet (UV) lasers, photochemical sensors, photocatalysts, and so on. Such 1-D nanowires could be easily achieved due to the anisotropic growth rate along the [0001] direction. However, such typical growth habit leads to decrease the surface area of the (0001) plane, which plays a central role in not only UV lasing action but also photocatalytic reaction. This fact lead us to develop ZnO crystal with enhanced polar surface area through crystal growth control. The purpose of this review is to provide readers a simple route to plate-type ZnO crystal with highly enhanced polar surfaces and their applications for UV-laser, photocatalyst, and antibacterial agents. In addition, we will highlight the recent study on pilot-scale synthesis of plate-type ZnO crystal for industrial applications.

• Proceedings of the Safety Management and Science Conference
• /
• 2012.04a
• /
• pp.421-433
• /
• 2012

The objective of this study is to obtain the optimal process condition and the maximum decomposition efficiency by measuring the decomposition efficiency, electricity consumption, and voltage in accordance with the change of the process variables such as the frequency, maintaining time period, concentration, electrode material, thickness of the electrode, the number of windings of the electrode, and added materials etc. of the harmful atmospheric contamination gases such as NO, $NO_2$, and $SO_2$etc. with the plasma which is generated by the discharging of the specially designed and manufactured $TiO_2$ catalysis reactor and SPCP reactor.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.1
• /
• pp.121-132
• /
• 2013

The objective of this study is to maintain the same frequency as the electrode material, concentration, duration of decomposition efficiency, power consumption and voltage measurements using a composite catalyst according to the change of process parameters to obtain the optimum state of the process and the maximum decomposition efficiency. In this paper, known as a major cause of air pollution, such as NO, NO2, SO2, frequency, flow rate, concentration, the material of the electrodes, and using TiO2 catalyst reactor with surface discharge caused by discharging the reactor plasma NOx, SOx decompose the harmful gas want to remove.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.1561-1565
• /
• 2008

More than 3.4 million people use Hong Kong metro a day. It was first constructed in 1979, and extended to 9 operating lines with 168.1km length operated by Hong Kong Mass Transit Railway Corporation (MTR). In Hong Kong, airborne viruses such as avian influenza (bird's flu) and severe acute respiratory syndrome (SARS), air pollution by high-density traffics, bacteria and mold due to relatively high humidity are major concerns on air quality management. In this study, we focused on the cases for improving indoor air quality conducted by Hong Kong MTR currently. The case includes the photocatalytic coatings on knobs (or hand straps) to prevent outbreak of bird's flu and SARS, the high voltage ionizers installed at metro platform, and the periodical radon monitoring.

• Elastomers and Composites
• /
• v.51 no.1
• /
• pp.31-37
• /
• 2016

In this study, we studied the photocatalytic functionality such as deodorant, antibacterial, antistatic of polyester fabrics treated with visible-light responsive photocatalyst. According to UV/visible spectrometry result, the UV-visible peak of visible-light responsive photocatalyst was found to be red shift at 420 nm sensitive in the visible light region. Also, the deodorizing and antimicrobial performance were shown to be retained more than 99% both before washing and even after 25 times washing. According to washing durability of polyester fabrics treated with visible-light responsive photocatalyst, the reduction effects for gas such as ammonia, trimethylamine, formaldehyde and toluene after 25 times washing appeared to be retained as much as before washing. At both before washing and after 25 times washing, antistatic property showed frictional voltage of approximately 250V.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.87-88
• /
• 2002

환경오염물질 정화를 위하여 다양하게 시도되고 있는 광촉매는 특별한 장치나 시설 없이 자외선을 에너지원으로 오염물질을 효과적으로 산화분해 시킬 수 있기 때문에 환경 친화적일 뿐만 아니라 경제적인 잇점을 가지고 있다. 그러나 아직까지 본격적인 실용화를 위해서는 선결해야 될 몇 가지 문제가 남아 있다 특히, 환경정화분야에서 광촉매를 적용하기 위해서는 광촉매 입자의 효과적인 코팅이 필수적이다. 광촉매 입자의 코팅은 지지체의 종류와 광촉매의 특성에 따른 최적조건을 찾아 주어야 하는데, 기본적으로 지지체와 광촉매 입자간의 결합 상태가 우수해야하며, 동시에 대상물질제거에 부합할 만한 광촉매 활성을 만족시켜야 한다. (중략)

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.955-956
• /
• 2006

Fe-doped $TiO_2$ nanopowders were prepared by mechanical alloying (MA) varying Fe contents up to 8.0 wt.%. The UV-vis absorption showed that the UV absorption for the Fe-doped powder shifted to a longer wavelength (red shift). The absorption threshold depends on the concentration of nano-size Fe dopant. As the Fe concentration increased up to 4 wt.%, the UV-vis absorption and the magnetization were increased. The benefical effect of Fe doping for photocatalysis and ferromagnetism had the critical dopant concentration of 4 wt.%. Based on the UV absorption and magnetization, the dopant level is localized to the valence band of $TiO_2$.

• Current Photovoltaic Research
• /
• v.5 no.4
• /
• pp.122-134
• /
• 2017

As a promising solution to global warming and growing energy demand, photocatalytic $CO_2$ conversion to useful fuels is widely studied to enhance the activity and selectivity of the $CO_2$ photoreduction reactions. In this review, an overview of fundamental aspects of the $CO_2$ reduction photocatalysts is provided. The recent development of the photocatalyst is also discussed, focusing on the mechanisms of light harvesting and charge transfer. Besides, this review sets its sight on inspiring new ideas toward a practical $CO_2$ conversion technology.