http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Theoretical insights into selective electrochemical conversion of carbon dioxide
Byoung Koun Min,Chanyeon Kim,Chan Woo Lee 나노기술연구협의회 2019 Nano Convergence Vol.6 No.8
Electrochemical conversion of CO2 and water to valuable chemicals and fuels is one of the promising alternatives to replace fossil fuel-based processes in realizing a carbon–neutral cycle. For practical application of such technologies, suppressing hydrogen evolution reaction and facilitating the activation of stable CO2 molecules still remain major challenges. Furthermore, high production selectivity toward high-value chemicals such as ethylene, ethanol, and even n-propanol is also not easy task to achieve. To settle these challenges, deeper understanding on underlying basis of reactions such as how intermediate binding affinities can be engineered at catalyst surfaces need to be discussed. In this review, we briefly outline recent strategies to modulate the binding energies of key intermediates for CO2 reduction reactions, based on theoretical insights from density functional theory calculation studies. In addition, important design principles of catalysts and electrolytes are also provided, which would contribute to the development of highly active catalysts for CO2 electroreduction.
Kim, Min-woo,Yoon, Hyun,Ohm, Tae Yoon,Jo, Hong Seok,An, Seongpil,Choi, Sung Kyu,Park, Hyunwoong,Al-Deyab, Salem S.,Min, Byoung Koun,Swihart, Mark T.,Yoon, Sam S. Elsevier BV 2017 Applied Catalysis B Vol.201 No.-
<P><B>Abstract</B></P> <P>We report the fabrication and performance of a CuO/ZnO/TiO<SUB>2</SUB> nanofiber photocathode that achieved a photocurrent density (PCD) of −4.1mA/cm<SUP>2</SUP>, which is among the highest PCD values reported for a copper oxide based photocathode without a co-catalyst. To prepare this photocathode, we coated electrospun nanofibers with copper by electroplating, then dried them in air to produce cuprous oxide (Cu<SUB>2</SUB>O) nanofibers. Further annealing in air converted them to cupric oxide (CuO). The CuO nanofibers exhibit nanotextured surfaces, resembling the skin of the “thorny-devil” lizard of Australia, providing high accessible surface area for photocatalysis. These CuO nanofibers were uniformly coated with thin ZnO and TiO<SUB>2</SUB> layers by atomic layer deposition (ALD) to promote electron migration from CuO to TiO<SUB>2</SUB> and protect the CuO from corrosion. The nanofibrous photocathode films were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy, as well as by incident photon-to-electron conversion efficiency measurements.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The fabrication of a CuO/ZnO/TiO<SUB>2</SUB> nanofiber photocathode has been reported. </LI> <LI> We achieved a photocurrent density (PCD) of −4.1mA/cm<SUP>2</SUP> without a co-catalyst. </LI> <LI> Electrospun nanofibers were electroplated with copper and then air-dried and annealed. </LI> <LI> The cupric CuO nanofibers exhibited nanotextured surfaces. </LI> <LI> These CuO nanofibers were coated with ZnO and TiO<SUB>2</SUB> by atomic layer deposition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Solar-hydrogen Production by a Monolithic Photovoltaic-electrolytic Cell
Jeon, Hyo Sang,Min, Byoung Koun The Korean Electrochemical Society 2012 Journal of electrochemical science and technology Vol.3 No.4
Among the various solar-hydrogen production techniques a combination of a photovoltaic (PV) and an electrolytic cell into one single system, a monolithic PV-electrolytic cell, has been suggested as a promising one in terms of efficiency and stability. In this mini-review, we describe our recent efforts on the fabrication of the monolithic PV-electrolytic cell. Particularly, we focus on the electrocatalysts for water oxidation and its fabrication method suitable for a monolithic PV-electrolytic cell. We also introduce proto-type devices with a dye-sensitized solar cell module and an InGaP/GaAs photoelectrodes.
Byungwoo Kim,정혜근,Byoung Koun Min,김홍곤,김웅 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.12
We demonstrate that vertically aligned carbon nanotubes can be synthesized directly on tantalum substrate via waterassisted chemical vapor deposition and evaluate their properties as electrochemical capacitors. The mean diameter of the carbon nanotubes was 7.1 ± 1.5 nm, and 70% of them had double walls. The intensity ratio of G-band to D-band in Raman spectra was as high as 5, indicating good quality of the carbon nanotubes. Owing to the alignment and low equivalent series resistance, the carbon nanotube based supercapacitors showed good rate performance. Rectangular shape of cyclic voltammogram was maintained even at the scan rate of > 1 V/s in 1 M sulfuric acid aqueous solution. Specific capacitance was well-retained (~94%) even when the discharging current density dramatically increased up to 145 A/g. Consequently, specific power as high as 60 kW/kg was obtained from as-grown carbon nanotubes in aqueous solution. Maximum specific energy of ~20 Wh/kg was obtained when carbon nanotubes were electrochemically oxidized and operated in organic solution. Demonstration of direct synthesis of carbon nanotubes on tantalum current collectors and their applications as supercapacitors could be an invaluable basis for fabrication of high performance carbon nanotube supercapacitors.
Piao, Longhai,Lee, Kyung-Hoon,Min, Byoung-Koun,Kim, Woong,Do, Young-Rag,Yoon, Sung-Ho Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.1
Size-controlled Ag nanoparticles (NPs) were prepared from the decomposition of Ag(I) carboxylates using ethanolamine derivatives as a reducing agent without an additional stabilizing agent. The size of the Ag NPs with a narrow size distribution (sub-10 nm to ca. 40 nm) was controlled precisely by varying the processing parameters, such as the type of reducing agent and the chain length of the carboxylate in the Ag(I) carboxylate. The optical properties, surface composition and crystallinity of the Ag NPs were characterized by ultraviolet-visible spectroscopy, gas chromatography-mass spectrometry, thermal gravimetric analysis, transmission electron microscopy and X-ray diffraction.
Kim, Byung-Woo,Chung, Hae-Geun,Min, Byoung-Koun,Kim, Hong-Gon,Kim, Woong Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.12
We demonstrate that vertically aligned carbon nanotubes can be synthesized directly on tantalum substrate via water-assisted chemical vapor deposition and evaluate their properties as electrochemical capacitors. The mean diameter of the carbon nanotubes was $7.1{\pm}1.5\;nm$, and 70% of them had double walls. The intensity ratio of G-band to D-band in Raman spectra was as high as 5, indicating good quality of the carbon nanotubes. Owing to the alignment and low equivalent series resistance, the carbon nanotube based supercapacitors showed good rate performance. Rectangular shape of cyclic voltammogram was maintained even at the scan rate of > 1 V/s in 1 M sulfuric acid aqueous solution. Specific capacitance was well-retained (~94%) even when the discharging current density dramatically increased up to 145 A/g. Consequently, specific power as high as 60 kW/kg was obtained from as-grown carbon nanotubes in aqueous solution. Maximum specific energy of ~20 Wh/kg was obtained when carbon nanotubes were electrochemically oxidized and operated in organic solution. Demonstration of direct synthesis of carbon nanotubes on tantalum current collectors and their applications as supercapacitors could be an invaluable basis for fabrication of high performance carbon nanotube supercapacitors.