As a promising anode for sodium-ion batteries (SIBs), cobalt sulfide ( CoS2) has attracted extensive attention due to its high theoretical capacity, easy preparation, and superior electrochemical activity. However, its intrinsic low conductivity and large volume expansion result in poor cycling ability. Herein, nitrogen-doped carbon-coated CoS2 nanoparticles (N–C@ CoS2) were prepared by a C3N4 soft-template-assisted method. Carbon coating improves the conductivity and prevents the aggregation of CoS2 nanoparticles. In addition, the C3N4 template provides a porous graphene-like structure as a conductive framework, affording a fast and constant transport path for electrons and void space for buffering the volume change of CoS2 nanoparticles. Benefitting from the superiorities, the Na-storage properties of the N–C@CoS2 electrode are remarkably boosted. The advanced anode delivers a long-term capacity of 376.27 mAh g− 1 at 0.1 A g− 1 after 500 cycles. This method can also apply to preparing other metal sulfide materials for SIBs and provides the relevant experimental basis for the further development of energy storage materials.

Recently, hollow carbon spheres (HCS) have aroused great interests in the field of energy storage and conversion owing to their unique morphology, structure and other charming properties. Nevertheless, unsatisfactory electrical conductivity and relatively poor volumetric energy density caused by inevitable gaps between discrete carbon spheres greatly impede the practical application of HCS. In this work, for the first time we propose a novel dual-template strategy and successfully fabricate interconnected 3D hollow N-doped carbon network (HNCN) by a facile and scalable pyrolysis process. By systematical characterization and analysis, it can be found that HNCN is assembled by HCS and lots of mesoporous carbon. Compared to the counterparts, the obtained HNCN exhibits unique 3D interconnected architecture, larger specific surface area, hierarchical meso/macropore structure, higher structure defects, higher N doping amount and more optimized N configurations (especially for pyridinic-N and graphitic-N). As a result, these advantageous features endow HNCN with remarkably promoted electrochemical performance for supercapacitor and oxygen reduction reaction. Clearly, our proposed dual-template strategy provides a good guidance on overcoming the intrinsic shortcomings of HCS, which undoubtedly broadens their application in energy storage and conversion.

본 연구에서는 고순도의 모데나이트(Mordenite) 입자를 합성하기 위하여 천연 제올라이트를 시드로 사용하여 시 드의 농도 및 수열합성 시간에 따른 천연 제올라이트 시드가 합성에 미치는 영향을 고찰하였다. 그 결과 시드가 입자의 형성 에 큰 영향을 끼치는 것을 확인할 수 있었고 시드를 3 g/100 g batch 주입하여 140°C에서 72시간 동안 수열합성을 진행하였 을 때 1-2 μm 사이즈의 고순도 모데나이트 입자를 합성할 수 있었다. 이를 통해 모데나이트 입자의 성장 기구를 규명할 수 있었으며, 모데나이트 입자 형성에 있어 시드는 첫째, 구형 모데나이트 전구체 형성 자리 공급의 역할과, 둘째 모데나이트 원 료 물질 소스 역할을 한다는 것을 알 수 있었다. 합성된 모데나이트 입자의 가스 흡착량 분석 결과 CO2 기체의 흡착량이 97.19 mg/g로 다른 가스들에 비해 비교적 높은 흡착성능을 보였으며, CO2/H2의 선택도가 가장 우수한 것으로 나타났다. 따라 서 이러한 결과들을 바탕으로 용도에 맞는 고순도 상의 모데나이트 입자를 합성할 수 있음을 확인하였고 보다 낮은 가격으로 우수한 분리성능을 갖는 분리막 소재개발에 활용할 수 있을 것이라 판단된다.

본 연구에서는 고순도의 모데나이트 입자를 합성하기 위하여 천연 제올라이트를 시드로 사용하여 시드 농도 및 수열합성 시간에 따라 시드가 미치는 영향 을 고찰하였다. 시드를 3 g/100g batch 주입하여 140°C에서 72시간 동안 수열 합성 하였을 때 1-2 μm 사이즈의 고순도 모데나이트 입자를 안정적으로 합성할 수 있었다. 이를 통해 천연 제올라이트 시드는 모데나이트 입자의 성장에서 구형 모데나이트 전구체 형성 자리를 공급하고 모데나이트 원료 물질 소스 역 할을 한다는 것을 알 수 있었다. 이러한 결과들을 바탕으로 용도에 맞는 고순도 의 모데나이트 입자를 합성할 수 있음을 확인하였고 천연제올라이트를 사용함으로써 낮은 가격으로 우수한 성능을 갖는 소재개발에 활용할 수 있을 것이라 판단된다.

In this work, uniform and nanosize(75nm) silicalite-1 crystals was hydrothermally synthesized by using 9TPAOH:0.16NaOH:25Si:495H2O solution at 80 ℃. They were applied as seed in the secondary growth process for preparing silicalite-1 membrane by template-free method. The highest ethanol/water separation factor of 119 with flux 0.58kg/m². Furthermore, these membranes (nano seed, template free silicalite-1 membrane) exhibit high permselectivity of He over SF6(123), and small gas permeation mechanism and Knudsen diffusion studies suggest that the membranes contain negligible intercrystalline or non-zeolite pores.

Perforated polygonal cobalt oxide (Co3O4) is synthesized using electrospinning and a hydrothermal methodfollowed by the removal of a carbon nanofiber (CNF) template. To investigate their formation mechanism, thermogravi-metric analysis, field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy are examined. To obtain the optimum condition of perforated polygonal Co3O4, we pre-pare three different weight ratios of the Co precursor and the CNF template: sample A (Co precursor:CNF template-10:1), sample B (Co precursor:CNF template-3.2:1), and sample C (Co precursor:CNF template-2:1). Among them, sam-ple A exhibits the perforated polygonal Co3O4 with a thin carbon layer (5.7-6.2 nm) owing to the removal of CNF tem-plate. However, sample B and sample C synthesized perforated round Co3O4 and destroyed Co3O4 powders, respectively,due to a decreased amount of Co precursor. The increased amount of the CNF template prevents the formation of polygonalCo3O4. For sample A, the optimized weight ratio of the Co precursor and CNF template may be related to the suc-cessful formation of perforated polygonal Co3O4. Thus, perforated polygonal Co3O4 can be applied to electrode materialsof energy storage devices such as lithium ion batteries, supercapacitors, and fuel cells.

Vertically oriented nickel nanowire arrays with a different diameter and length are synthesized in porous anodic aluminium oxide templates by an electrodeposition method. The pore diameters of the templates are adjusted by controlling the anodization conditions and then they are utilized as templates to grow nickel nanowire arrays. The nickel nanowires have the average diameters of approximately 25 and 260 nm and the crystal structure, morphology and microstructure of the nanowires are systematically investigated using XRD, FE-SEM and TEM analysis. The nickel nanowire arrays show a magnetic anisotropy with the easy axis parallel to the nanowires and the coercivity and remanence enhance with decreasing a wire diameter and increasing a wire length.

In this work, uniform and nanosize(75nm) silicalite-1 crystals was hydrothermally synthesized by using 9TPAOH:0.16NaOH:25Si:495H2O solution at 80 ℃. They were applied as seed in the secondary growth process for preparing silicalite-1 membrane by template-free method. And silicalite-1 membrane, which was coated by nano-size seed, showed a high EtOH/H2O separation factor of 128. The high separation factor could be explained by the role of nanosize seed. The application of nanosize seed successfully retarded the formation of interfacial voids between silicalite-1 grains. Therefore, it could be concluded that template-free hydrothermal process can produce silicalite-1 membrane with well performance.

Cobalt nano-rods were fabricated using a template-free electrochemical-deposition process. The structure of cobalt electro-deposits strongly depends on the electrolyte composition and on the density of the applied current. In particular, as the content of boric acid increased in the electrolyte, deposits of semi-spherical nuclei formed, and then grew into one-dimensional nano-rods. From analysis of the electro-deposits created under the conditions of continuous and pulsed current, it is suggested that the distribution of the active species around the electrode/electrolyte interface, and their transport, might be an important factor affecting the shape of the deposits. When transport of the active species was suppressed by lowering the deposition temperature, more of the well-defined nano-rod structures were obtained. The optimal conditions for the preparation of well-defined nano-rods were determined by observing the morphologies resulting from different deposition conditions. The maximum height of the cobalt nano-rods created in this work was 1μm and it had a diameter of 200 nm. Structural analysis proved that the nano-rods have preferred orientations of (111).

Single crystalline Cu nanowires with controlled diameters and aspect ratios have been synthesized using electrochemical deposition within confined nanochannels of a porous anodic aluminium oxide(AAO) template. The diameters of nano-sized cylindrical pores in AAO template were adjusted by controlling the anodization conditions. Cu nanowires with diameters of approximately 38, 99, 274 nm were synthesized by the electrodeposition using the AAO templates. The crystal structure, morphology and microstructure of the Cu nanowires were systematically investigated using XRD, FE-SEM, TEM and SAED. Investigation results revealed that the Cu nanowires had the controlled diameter, high aspect ratio and single crystalline nature.

양극산화 알루미나(AAO)막의 나노 사이즈 미세공(세공 크기 20 nm, 10 nm 및 200 nm)을 주형으로 사용하여 전도성 고분자인 폴리피롤, 폴리아닐린 중합체 및 폴리피롤/폴리아닐린 공중합체 나노와이어를 제조하였다. 미세공 주형 내에서 전도성 고분자의 성장은 세공의 벽면을 따라 튜브 형태로서 성장하였으며, 3시간 이후에는 내부가 완전히 채워진 나노와이어가 형성되었다. AAO 막을 수산화나트륨 용액으로 퍼리하여 세공 내에 형성된 전도성 고분자 나노와이어를 회수 하였으며. 회수된 나노와이어 직경과 길이는 주형 막의 세공 형상과 일치하였다. 통상의 용액 중합법으로 제조된 전도성 고분자 분말과 비교하여 주형 합성법으로 제조된 전도성 고분자 나노와이어는 결정성과 열적 안정성이 향상되었으며, 전기 저항은 4~60% 감소하였다.

As a growth-template of ZnO nanorods (NR), a hexagonal β-Ni(OH)2 nanosheet (NS) was synthesized with the low temperature hydrothermal process and its microstructure was investigated using a high resolution scanning electron microscope and transmission electron microscope. Zinc nitrate hexahydrate was hydrolyzed by hexamethylenetetramine with the same mole ratio and various temperatures, growth times and total concentrations. The optimum hydrothermal processing condition for the best crystallinity of hexagonal β-Ni(OH)2 NS was determined to be with 3.5 mM at 95˚C for 2 h. The prepared Ni(OH)2 NSs were two dimensionally arrayed on a substrate using an air-water interface tapping method, and the quality of the array was evaluated using an X-ray diffractometer. Because of the similarity of the lattice parameter of the (0001) plane between ZnO (wurzite a = 0.325 nm, c = 0.521 nm) and hexagonal β-Ni(OH)2 (brucite a = 0.313 nm, c = 0.461 nm) on the synthesized hexagonal β-Ni(OH)2 NS, ZnO NRs were successfully grown without seeds. At 35 mM of divalent Zn ion, the entire hexagonal β-Ni(OH)2 NSs were covered with ZnO NRs, and this result implies the possibility that ZnO NR can be grown epitaxially on hexagonal β-Ni(OH)2 NS by a soluble process. After the thermal annealing process, β-Ni(OH)2 changed into NiO, which has the property of a p-type semiconductor, and then ZnO and NiO formed a p-n junction for a large area light emitting diode.