• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.1276-1276
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• 2005

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.402.2-402.2
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• 2016

In photoelectrochemical (PEC) water splitting, Cu2ZnSnS4 (CZTS) compound has attracted intense attention as a photocathode due to not only large optical absorption coefficient, but also earth-abundance of constituent elements and suitable band alignment. With rapid development of nanotechnology, one-dimensional nanostructures of CZTS have been investigated as a potential form to achieve high efficiency because the nanostructures are expected to be capable of capturing more light and enhancing charge separation and transport. Here, we report a well-controlled fabrication route for vertically-aligned CZTS nanorod arrays on anodic aluminium oxide (AAO) template via simple sol-gel process followed by deposition of ZnS or CdS buffer layers on the CZTS nanorod to enhance charge separation. The structure, morphology, composition, optical absorption, and PEC properties of the resulting CZTS nanorod samples were characterized using X-ray diffraction, Raman spectroscopy, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy, and UV-vis spectroscopy.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.401-401
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• 2016

Although vertically aligned one-dimensional (1D) structure has been considered as efficient forms for photoelectrode, development of efficient 1D nanostructured photocathode are still required. In this sense, we recently demonstrated a simple fabrication route for CuInS2 (CIS) nanorod arrays from aqueous solution by template-assisted growth-and-transfer method and their feasibility as a photoelectrode for water splitting. In this study, we further evaluated the photoelectrochemical properties surface-modified CIS nanorod arrays. Surface modification with CdS and ZnS was performed by successive ion layer adsorption and reaction (SILAR) method, which is well known as suitable technique for conformal coating throughout nanoporous structure. With surface modification of CdS and ZnS, both photoelectrochemical performance and stability of CuInS2 nanorod arrays were improved by shifting of the flat-band potential, which was analyzed both onset potential and Mott-schottky plot.

• KIEAE Journal
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• 제4권2호
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• pp.37-40
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• 2004

New visible photocatalyst(Nanovis$^{(R)}$) has been synthesized to overcome the barrier of limitation of UV light utilization of current $TiO_2$ photocatalyst. It was found that red shift of absorption spectrum to 550nm was achieved. Its physical properties were characterized by XRD, BET and TEM. It is also observed that Nanovis$^{(R)}$ has a photocatalytic activity for photodegradation of Trichloroethylene under visible light irradiation. V,VII group doped into substitutional sites of $TiO_2$ has proven to be indispensable for band-gap narrowing and photocatalytic activity. These test results lead us to conclude that Nanovis$^{(R)}$ can be used for IAQ improvemen and for photocatalytic water splitting to hydrogen.

• 태양에너지
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• 제8권1호
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• pp.49-56
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• 1988

Thermally treated Korean ilmenite was characterized and used for water splitting to obtain hydrogen by photo-catalytic reaction. Experiments on specific surface area, X-ray diffraction and EDS showed that the formation of FeO, $Fe_2O_3$ and $TiO_2$ ilmenite crystal surface increased the specific surface area with maximum value, phase change of $TiO_2$ at $600^{\circ}C$ and hetrogeneity. The hydrogen evolved in caustic soda solution on these ilmenites indicated that there was a maximum yield point at about $600^{\circ}C$. This point was explained with the change of the surface area due to sintering of newly formed FeO, $Fe_2O_3$ and $TiO_2$, as well as crystal phase change of anatase to rutile at $600^{\circ}C$. Produced hydrogen increased also as the concentration of caustic soda, but become constant at the near 1N solution.

• 한국막학회:학술대회논문집
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• 한국막학회 2005년도 추계 총회 및 학술발표회
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• pp.119-123
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• 2005

The thermochemical splitting of water has been proposed as a clean method for hydrogen production. The IS process is one of the thermochemical water splitting processes using iodine and sulfur as reaction agents. HI decomposition procedure to obtain hydrogen is one of the key operations in the process, because equilibrium conversion of HI is low (22% at $450^{\circ}C$). The silica membranes prepared by CVD. method were applied to the decomposition reaction of HI vapor. The permeation characteristics of hydrogen and nitrogen belong to the Knudsen flow pattern.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.101-101
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• 2015

Photoelectrochemical water splitting is considered as a promising method of transforming solar energy into chemical energy stored in the type of hydrogen. An n-type $WO_3$ semiconductor is one of the most promising photoanodes for hydrogen production from water splitting. Films annealed at lower temperatures consisted of amorphous, whereas films annealed above $500^{\circ}C$ comprised solely of monoclinic $WO_3$. In this study, we observed photoactivity of $WO_3$ as increasing thickness of $WO_3$. And it shows good photoacivity as thickness increases. Also we tried to improve photoactivity through surface modification and bulk modification by using hydrogen treatment and conducting polymer. The photocurrent was measured in potentiostatic method with the three electrode system. A Pt wire and Ag / AgCl electrode were used as the counter electrode and the reference electrode, respectively. photocurrent-time (I-T) curve was measured at a bias potential of 0.79 V.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.39-45
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• 2020

The Cu/Cu2O/CuO photoelectrode has been successfully fabricated by Rapid Thermal Annealing technique. The structural characterization of fabricated photoelectrode was performed using X-Ray diffraction, while elemental composition of the prepared material has been checked with X-Ray Photoelectron Spectroscopy. The synthesis parameters are optimized on the basis of photoelectrochemical performance. The best photoelectrochemical performance has been observed for the Cu/Cu2O/CuO photoelectrode fabricated at 550 ℃ oxidation temperature and oxidation time of 50 seconds with highest photocurrent density of -3 mA/㎠ at -0.13 V vs. RHE.

• Rapid Communication in Photoscience
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• 제3권2호
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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.

• 한국태양에너지학회 논문집
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• 제37권2호
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• pp.13-22
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• 2017

Two-step water splitting thermochemical cycle with $CeO_2/ZrO_2$ foam device was investigated by using a solar simulator composed of 2.5 kW Xe-Arc lamp and mirror reflector. The hydrogen production of $CeO_2/ZrO_2$ foam device depending on heat recovery of Thermal-Reduction step and Water-Decomposition step was analyzed, and the hydrogen production of $CeO_2/ZrO_2$ and $NiFe_2O_4/ZrO_2$ foam devices was compared. Resultantly, the quantity of hydrogen generation increased by 52.02% when the carrier gas of Thermal-Reduction step is preheated to $200^{\circ}C$ and, when the $N_2/steam$ is preheated to $200^{\circ}C$ in the Water-Decomposition step, the quantity of hydrogen generation increased by 35.85%. Therefore, it is important to retrieve the heat from the highly heated gases discharged from each of the reaction spaces in order to increase the reaction temperature of each of the stages and thereby increasing the quantity of hydrogen generated through this.