텅스텐카바이드(WCs) 기반의 전기화학적 촉매에 관한 연구

DoctorTransition metal carbides (TMCs) have been attracted as catalysts because of their noticeable catalytic properties. In addition, their refractory properties can give resistance against sintering and corrosion under reaction such as acidic and basic condition. They have outstanding catalysis in many reactions, particularly those hydrogen involved reactions such as hydrotreating, hydrogenation, dehydrogenation, isomerization, hydrogenolysis, reforming, and aromatization so on. Recently they are also receiving attention as elecrocatalysts. In many of these reactions, metal carbides behave like Group 8？10 metals (noble metals such as Pt) of high cost and limited supply and have potential to reduce or replace them. Especially, in low temperature fuel cell system, tungsten carbide is most attractive material due to their Pt-like behavior, high electric conductivity and CO resistance so on. Thus tungsten carbide based materials have been applied to low temperature fuel cells (DMFC, PEMFC) as anodic and cathodic electrode materials. However, the intrinsic catalysis of tungsten carbide itself is too much lower than that of platinum. In many catalytic system, small amount of metals including noble species have been used with tungsten carbides for synergistic effect between tungsten carbides and metals for high electrochemical activities related with low temperature fuel cells.Tungsten carbides have been specified by various phases such as tungsten mono-carbide (WC), tungsten di-carbide (W2C) and tungsten partial oxidized form (WC1-x). Among them, WC has been reported as high electrochemical activity and stability in acidic condition like low temperature fuel cells than other tungsten carbides. In this point of view, various tungsten carbides have been synthesized and analyzed including the electrochemical characterization concentrated tungsten mono-carbide (WC). In this work, tungsten carbides (WCs) which preserved the outstanding physicochemical properties were fabricated via new economic strategy specified by polymer induced carburization. The phases of tungsten carbides were controlled throughout the various synthetic pathways in polymer formation step such as refluxing and hydrothermal reaction. The polymer intermediates were calcined under inert and reducing atmosphere specified by using gases at high temperature. Conventionally, metal oxides have been utilized by the precursor for metal carbides fabricated by temperature programmed reaction (TPR) process. The physicochemical properties of metal oxides could affect to the final product, metal carbides. For 1-D nanowire types tungsten oxides were synthesized by microwave-assisted hydrothermal method, and these 1-D structures would be employed by precursor for 1-D tungsten carbides. For this unique structural tungsten oxides were made by effective strategy, and the fundamental electrochemical properties focused on the hydrogen evolution reaction (HER) were included due to the pivotal possibility to tungsten carbides.In methanol oxidation reaction (MOR), the objective was a reduction of Pt amount with tungsten carbides. Generally, WCs have played a role as booster species for methanol oxidation to generate the methoxy group not easily shown in Pt metal due to the outstanding dehydrogenation property. The generated methoxy groups were spilled over on Pt metals, and the sequent reaction was actively occurred. And also, the CO tolerance via bifunctional effect was one of the pivotal roles of WCs shown in Ru containing electrocatalysts. Thus the amount of Pt could be reduced, and Ru could be almost replaced by WCs. For these information, Pt and PtRu alloy were loaded on fabricated tungsten carbides (WCs) via chemical reduction method (CR) and polyol method (Polyol), and metal loaded WCs were evaluated for application to the methanol oxidation reaction (MOR) in initial stage. Among the same metal loaded WCs, mesoporous tungsten mono-carbide (WC) nanoparticles indicated the outstanding electroactivity in MOR analyzed by half and single cell conditions. Therefore, mesoporous WC nanoparticles were focused on the best electrocatalysts and support materials for other metals. Firstly, the single cell performances were embodied with small amount of PtRu loaded WC nanoparticles, and the mass activity was higher than that of same amount of PtRu loaded carbon electrocatalysts.For hydrogen oxidation reaction (HOR), the efforts to find out the non-Pt electrocatalysts based on the WC nanoparticles via the combination with non-Pt metals. In HOR, WC nanoparticles have shown the electroactivity. However, when Pd based metals were loaded on WC nanoparticles, the electroactivity and stability could show the comparable grades to overcome the each foible of Pd and WC with Pt/C commercial electrocatalyst which has been in state-of-the-art. The synergistic phenomenon was observed by various techniques, and the unique and grand synergistic effects for HOR were introduced with the originations. For hydrogen evolution reaction (HER), the electrolysis of water has been a strategy of hydrogen production from renewable. The efficiency of water electrolysis has depended critically on cathode materials. The most popular cathode material for HER in acidic media was Pt metal. However, high loadings of these expensive noble metals have been needed, which makes the cost of water electrolysis prohibitively high. New cathodic materials have been urgently needed to replace these noble metals with less expensive materials, or reduce their usage. Therefore, cathodic electrocatalysts would be introduced by tungsten di-carbides and 1-D tungsten oxide nanowires which could be precursors for 1-D tungsten carbides.Synthesis, material characterization, various metal loading (including the characterizations) and electrochemical investigations will be treated in regular sequence

Enhanced electroactivities of Tungsten carbides supported catalysts for low temperature fuel cells

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Enhanced Electrochemical activity of PtNi decorated Mesoporous WC Nanoparticles for Low Temperature Fuel Cells

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Electrochemical hydrogen evolution over WO3 and MoO3 nanowires produced by microwave-assisted hydrothermal reaction

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Synthesis of Electrocatalysts for Electrooxidation of Methyl Formate and Their Activity under Half Cell and Single Cell Condition

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Electrocatalysts for Electrooxidation of Methly Formate

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A deep-sea eelpout Pachycara matallanasi (Perciformes: Zoarcidae: Lycodinae) from the Eastern North Pacific Ocean

The zoarcid genus Pachycara Zugmayer, 1911 comprising 27 deep-sea eelpouts, all inhabiting the upper bathyal to abyssal zone, 13 species in the Pacific Ocean and 14 species in the Atlantic, Indian and/or Antarctic Oceans. And then type specimens of 27 species were collected between 300 m and 4,450 m depth. Considerable systematic confusion exists in the genus Pachycara and various reviews have tried to establish diagnostic characters. The Pachycara is defined by a combination of the following characters: body robust flesh firm pelvic fins, scales, lateral line(s) and pseudobranch filaments present or absent suborbital pores 5-7 vomerine and palatine teeth present mental crest absent suborbital bones 6-8 parasphenoid wing below mid-height of trigeminofacialis foramen platopterygoid series well developed pyloric caeca present total vertebrae 92-125. A deep-sea eelpout Pachycara matallanasi Corbella and Møller, 2014 was described from the Solomon Sea, Western South Pacific at 7°49′4″S, 156°02′8″E, December 2006, around 4,400 m depth. And, three specimens of P. matallanasi were additionally collected from the Eastern North Pacific at 10°32′4″N, 131°55′4″W during the Korea Deep Ocean Study (KODOS) of KIOST, R/V ONNURI, February 2014, by a Bait-trap Lander, around 5,100 m depth. Until now, only known from a single type locality in the Solomon Sea, and from the locality to the sampling site of this stimens of 27 species were collected between 300 m and 4,450 m depth. Considerable systematic confusion exists in the genus Pachycara and various reviews have tried to establish diagnostic characters. The Pachycara is defined by a combination of the following characters: body robust flesh firm pelvic fins, scales, lateral line(s) and pseudobranch filaments present or absent suborbital pores 5-7 vomerine and palatine teeth present mental crest absent suborbital bones 6-8 parasphenoid wing below mid-height of trigeminofacialis foramen platopterygoid series well developed pyloric caeca present total vertebrae 92-125. A deep-sea eelpout Pachycara matallanasi Corbella and Møller, 2014 was described from the Solomon Sea, Western South Pacific at 7°49′4″S, 156°02′8″E, December 2006, around 4,400 m depth. And, three specimens of P. matallanasi were additionally collected from the Eastern North Pacific at 10°32′4″N, 131°55′4″W during the Korea Deep Ocean Study (KODOS) of KIOST, R/V ONNURI, February 2014, by a Bait-trap Lander, around 5,100 m depth. Until now, only known from a single type locality in the Solomon Sea, and from the locality to the sampling site of this st2

Device for reducing pollution of sea water when distribute it

본 발명은 오염저감형 해수 시료 분배 기구를 공개한다. 이 기구는, 해수 시료의 분배에 있어서, 해수 시 료의 중간저장을 위한 저장용기 및 상기 저장용기가 거치되는 거치대 를 포함하며, 상기 저장용기는, 상 기 저장용기의 캡(cap)에 배치되며 니스킨 채수기(Niskin water sampler)로부터 해수 시료를 공급받기 위 한 취수부 상기 취수부와 연결되며 상기 취수부로 해수가 역류하지 않도록 상기 저장용기의 바닥면과 가 깝게 배치되는 역류방지관(overflow pipe) 및 상기 저장용기의 캡에 배치되며 상기 저장용기로부터 해수 시료를 분배하기 위한 분배부 를 포함하고, 상기 거치대는, 상기 저장용기가 놓이는 거치부 상기 거치부 에 배치되며 상기 저장용기를 고정시키기 위한 고정부 및 상기 거치부를 지지하는 지지부 를 포함한다

Characterizing Geomorphological Properties of Western Pacific Seamounts for Cobalt-rich Ferromanganese Crust Resource Assessment

We characterize the spatial distribution of Cobalt-rich ferromanganese crusts covering the summit and slopes of a seamount in the western Pacific, using acoustic backscatter from multibeam echo sounders (MBES) and seafloor video observation. Based on multibeam bathymetric data, we identify that ~70% of the summit area of this flattopped seamount has slope gradients less than 5∘ . The histogram of the backscatter intensity data shows a bi-modal distribution, indicating significant variations in seabed hardness. On the one hand, visual inspection of the seafloor using deep-sea camera data exhibits that the steep slope areas with high backscatter are mainly covered by manganese crusts. On the other hand, the visual analyses for the summit reveal that the summit areas with relatively low backscatter are covered by sediments. The other summit areas, however, exhibit high acoustic reflectivity due to coexistence of manganese crusts and sediments. Comparison between seafloor video images and acoustic backscatter intensity suggests that the central summit has relatively flat topography and low backscatter intensity resulting from unconsolidated sediments. In addition, the rim of the summit and the slopes are of high acoustic reflectivity because of manganese crusts and/or bedrock outcrops with little sediments. Therefore, we find a strong correlation between the acoustic backscatter data acquired from sea-surface multibeam survey and the spatial distribution of sediments and manganese crusts. We propose that analyzing acoustic backscatter can be one of practical methods to select optimal minable areas of the ferromanganese crusts from seamounts for future mining. 서태평양 공해 해저산의 다중빔 음향측심자료와 해저면 영상관측 자료를 활용하여 해저산 정상부와 경사면에 피복된 망간각의 공간 분포 변화 양상을 파악하였다. 다중빔 음향측심기를 이용하여 구분된 해저산의 지형 특성은 정상부 면적의 약 70% 이상이 경사가 5∘ 미만으로 비교적 평평한 지대로 이루어져 있으나 후방산란강도는 해저면의 매질변화를 지시하는 이봉분포를 보였다. 이 이봉분포에서 -30 dB이상의 높은 최빈값은 경사면과 정사부 가장자리 지역에서 우세하였으며 -30 dB이하의 낮은 최빈값은 정상부 중앙지역에서 우세하였다. 해저면 표층의 영상자료와 후방산란 자료의 연관성을 분석한 결과, 정상부 중앙지역은 경사면에 비해 상대적으로 완만한 기울기와 미교결 퇴적물만 존재하여 후방산란이 낮게 나타난다. 반면, 정상부 가장자리 및 경사면은 퇴적물이 없어 기반암이 노출되거나 망간각이 피복되어 후방산란이 높게 나타남을 보여준다. 따라서 다중빔 음향측심조사를 통해 획득된 후방산란 자료와 해저면의 퇴적물 및 망간각 분포 사이의 상관관계가 높다는 것을 알 수 있다. 이 연구결과는 다중빔 음향측심조사를 통해 획득된 후방산란 자료를 활용하면 기요형태의 해저산에 피복된 망간각의 전체적인 분포 규모를 확인할 수 있음을 의미한다. 따라서 해저산 지역의 망간각 개발 유망구역을 선별하는데 후방산란 자료가 유용하게 활용될 수 있을 것이다.22Nkc

Promoted Palladium on Tungsten Carbides as Platinum-free Anode Catalysts for Polymer Electrolyte Fuel Cell

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