• 한국수소및신에너지학회논문집
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• 제24권6호
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• pp.550-557
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• 2013

A glucose hydrothermal method is described for preparing hollow carbon spheres (HCS), which have a regular morphology and a high Brunauer-Emmett-Teller surface area of 28.6 m2/g. Scanning electron microscopy shows that they have thin shells and diameter between 2 and 8 ${\mu}m$. The HCSs were modified for the enhanced room temperature hydrogen storage by employing Ni nanoparticles on their surface. The Ni-decorated HCSs were characterized by X-ray diffraction, transmission electron microscopy coupled with an energy dispersive spectroscope, and an inductively coupled plasma spectrometer, indicating that fine and well-distributed Ni nanoparticles can be accomplished on the HCSs. The hydrogen uptake capacity in HCSs with and without Ni loading was evaluated using a high-pressure microbalance at room temperature under a hydrogen pressure upto 9 MPa. As much as 1.23wt.% of hydrogen can be stored when uniformly distributed Ni nanoparticles are formed on the HCSs, while the hydrogen uptake capacity of as-received HCSs was 0.41 wt.%. For Ni nanoparticle-loaded HCSs, hydrogen molecules could be easily dissociated into atomic hydrogen and then chemically adsorbed by the sorbents, leading to an enhanced capacity for storing hydrogen.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.232-232
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• 2009

최근 WGS반응용 Pt 촉매의 성능 향상을 위한 다양한 담체 및 조촉매(Promotor) 개발에 대한 연구가 활발하게 진행되고 있다. 선행 연구결과, 입방(Cubic)구조를 가지는 $Ce_{0.8}Zr_{0.2}O_2$ 담체는 정방 입계(Tetragonal)구조를 가지는 $Ce_{0.2}Zr_{0.8}O_2$ 담체 또는 혼합산화물(Mixed oxide)구조를 가지는 $Ce_{0.5}Zr_{0.5}O_2$ 담체 보다 높은 활성과 안전성을 가진다. 이것은 촉매의 성능 향상이 Ce-$ZrO_2$의 결정구조에 의존한다는 것을 나타낸다. 따라서 WGS 반응에서 Ce/Zr 비에 따라 변화된 담체 특성이 Pt 촉매의 활성에 영향이 있을 것으로 예상되며 실험결과 1% Pt/$CeO_2$ 촉매가 가장 높은 활성을 나타내었다. 따라서 Pt/Ce-$ZrO_2$ 촉매의 성능 향상을 위해 Ce-$ZrO_2$ 담체에 조촉매인 Ni을 첨가하여 촉매적 활성을 비교하여 보았다. 촉매는 2%의 Pt과 15%의 Ni로 고정하였고 Ce/Zr 비를 제조변수로 하였다. 제조된 모든 담체는 공침법(Co-precipitation)을 사용하여 제조하였으며 $500^{\circ}C$에서 6시간 소성하였다. Pt 촉매는 함침법 (Incipient wetness impregnation)으로 담지 시켰다. 2% Pt/Ce-$ZrO_2$ 촉매와 2% Pt/15% Ni-Ce-$ZrO_2$ 촉매는 저온영역($200^{\circ}{\sim}320^{\circ}C$)에서 비슷한 CO 전환율을 나타내었으나 고온영역($360^{\circ}C{\sim}400^{\circ}C$)에서는 2% Pt/15% Ni-Ce-$ZrO_2$ 촉매가 더 높은 CO의 전환율을 나타내었다. 이것은 Ni의 영향으로 고온에서 부반응인 메탄화 반응(Methanation reaction)이 생긴 것으로 판단되어 메탄($CH_4$)의 선택도를 살펴본 결과 2% Pt/15% Ni-Ce-$ZrO_2$ 촉매가 고온영역($360^{\circ}{\sim}400^{\circ}C$)에서 급격하게 증가하는 것으로 나타나 메탄화 반응이 일어난 사실을 증명한다.

• 센서학회지
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• 제13권4호
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• pp.298-302
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• 2004

Thick films of $LaNiO_{3}$ having perovskite structure impregnated with indium and bismuth oxides have been used as sensing material for acetonitrile ($CH_{3}CN$) gas. The sensor response for $CH_{3}CN$ is quite good with an excellent recovery for partial pressure from 3 ppm to 20 ppm between 200 and $250^{\circ}C$. $LaNiO_{3}$ alone has exhibited low response, but after impregnation of $In_{2}O_{3}$ and $Bi_{2}O_{3}$ have given increased sensitivity even with 3 ppm partial pressure of $CH_{3}CN$ at $200^{\circ}C$. It is assumed that $CH_{3}CN$ is undergoing oxidation reaction on surface of the film.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3213-3218
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• 2014

A metal organic framework-supported Nickel nanoparticle (Ni-MOF-5) was successfully synthesized using a simple impregnation method. The obtained solid acid catalyst was characterized by Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption and thermogravimetric analysis (TGA). The catalyst was highly crystalline with good thermodynamic stability (up to $400^{\circ}C$) and high surface area ($699m^2g^{-1}$). The catalyst was studied for the oxidation of ethyl benzene, and the results were monitored via gas chromatography (GC) and found that the Ni-MOF-5 catalyst was highly effective for ethyl benzene oxidation. The conversion of ethyl benzene and the selectivity for acetophenone were 55.3% and 90.2%, respectively.

• Bulletin of the Korean Chemical Society
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• 제20권1호
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• pp.89-94
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• 1999

Carbon dioxide reforming of methane on Ni/γ-Al2O3 catalyst was studied. A new 10 wt% Ni/γ-Al2O3 catalyst prepared by the liquid phase oxidation method (L10O) exhibited much higher activity as well as resistances to both sintering and coke formation during the reaction than the catalyst prepared by the conventional impregnation method (D10). The electrically strong attractive interaction between nickel and support during the liquid phase oxidation process and the resultant high nickel dispersion made the L10 have superior activity and stability to the D10. To elucidate the results, the experiments with nickel catalysts on the other supports as well as 7-AI203 were performed. The effect of sodium as a promoter was also studied.

• 한국응용과학기술학회지
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• 제27권1호
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• pp.29-36
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• 2010

The effects of La addition to Ni/$CeO_2$ methane partial oxidation catalysts were investigated. Catalysts were prepared by the impregnation and urea methods. In the preparation of catalysts, La content was changed from 1 wt% to 3wt%. Catalysts that contain 2wt% La showed the highest methane conversion of about 80% and CO selectivity of 84% and $H_2$ selectivity of 70%. This result may be stemmed from that, when La content is 2wt%, a fluorite oxide-type structure is well formed and carbon deposition is also decreased. Among the catalysts, 2.5wt% Ni/Ce(La)Ox showed the highest catalytic activity. From the experiment of changing reaction temperature with 2.5wt% Ni/Ce(La)Ox catalyst, it was found that the optimum reaction temperature is $750^{\circ}C$ and at this temperature methane conversion was about 90%, CO and $H_2$ selectivities were 94 and 80%, respectively.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1273-1279
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• 2007

The NiSO4 supported on Fe2O3 catalysts were prepared by the impregnation method. No diffraction line of nickel sulfate was observed up to 30 wt %, indicating good dispersion of nickel sulfate on the surface of Fe2O3. The addition of nickel sulfate to Fe2O3 shifted the phase transition of Fe2O3 (from amorphous to hematite) to higher temperatures because of the interaction between nickel sulfate and Fe2O3. 20-NiSO4/Fe2O3 containing 20 wt % of NiSO4 and calcined at 500 oC exhibited a maximum catalytic activity for ethylene dimerization. The initial product of ethylene dimerization was found to be 1-butene and the initially produced 1-butene was also isomerized to 2-butene during the reaction. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method.

• Bulletin of the Korean Chemical Society
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• 제20권3호
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• pp.291-296
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• 1999

The immobilization of APTMS(3-(2-aminoethylamino)propyltrimethoxysilane) and AAPTMS(3-(2-(2-aminoethyl)aminoethylanino)propyltrimethoxysilane) on the surface of high quality mesoporous molecular sieves MCM-41 and MCM-48 have been confirmed by F.T.-IR spectroscopy, Raman spectroscopy, 29Si solid state NMR, and a surface polarity measurement using Reichardt's dye. The formation of metal (Co(Ⅱ), Ni(Ⅱ), and Cu(Ⅱ)) complexes by immobilized aminosilanes have been investigated by photoacoustic spectroscopy(PAS). The assignment of UV-Vis. PAS bands makes it possible to identify the structure of metal complexes within mesoporous molecular sieves. Co(Ⅱ) ion may be coordinated mainly in a tetrahedral symmetry by two APTMS onto MCM-41, and in an octahedral one by two AAPTMS. Both Ni(Ⅱ) and Cu(Ⅱ) coordinated by aminosilanes within MCM-41 form possibly the octahedral complexes such as [Ni(APTMS)2(H20)2]2+, [Ni(AAPTMS)2]2+, [Cu(APTMS)2(H2O)2]2+, and [Cu(AAPTMS)(H2O)3]2+, respectively. The PAS band shapes of complexes onto MCM-48 are similar to those of corresponding MCM-41 with the variation of PAS intensity. Most of metal ion(Ⅱ) within MCM-41 and MCM-48 are coordinated by aminosilanes without the impregnation on the surface.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.1-7
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• 2012

This study was performed to develop a low Pt content catalyst as a catalyst for HI decomposition in S-I process. Bimetallic catalysts added various amounts of Pt on a silica supported Ni catalyst were prepared by impregnation method. HI decomposition was carried out using a fixed bed reactor. As a result, Ni-Pt bimetallic catalyst showed enhanced catalytic activity compared with each monometallic catalyst. Deactivation of Ni-Pt catalyst was not observed while deactivation of Ni monometallic catalyst was rapidly occurred in HI decomposition. The HI conversion of Ni-Pt bimetallic catalyst was increased similar to Pt catalyst with increase of the reaction temperature over a temperature range 573K to 773K. From the TG analysis, it was shown that $NiI_2$ remained on the Ni(5.0)-Pt(0.5)/$SiO_2$ catalyst after the HI decomposition reaction was decomposed below 700K. It seems that small amount of Pt in bimetallic catalyst increase the decomposition of $NiI_2$ generated after the decomposition of HI. Consequently, it was considered that the activity of Ni-Pt bimetallic catalyst was kept during the HI decomposition reaction.

• 한국수소및신에너지학회논문집
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• 제21권1호
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• pp.26-34
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• 2010

The electrocatalystic prperties of Pt-Co and Pt-Ni with heteropolyacids (HPAs) entrapped in covalently cross-linked sulfonated poly(ether ether ketone) (CL-SPEEK)/HPA membranes were investigated for water electrolysis. The HP As, including molybdophosphoric acid (MoPA), and tungstophosphoric acid (TPA) were both used as membrane additives and electrocatalysts. The membrane electrode assembly (MEA) was prepared by a nonequilibrium impregnation-reduction (I-R) method. $Pt(NH_3)_4Cl_2$, $NiCl_2$ and $CoCl_2$ as electrocatalytic materials and $NaBH_4$ as reducing agent were used. I order to enhance electrocatalytic activity, the catalyst layer prepared above was electrodeposited (Dep) with HP A. Surface morphologies and physico-chemical properties of MEA were investigated by means of SEM, EDX and XRD. The electrocatalytic properties of composite membranes such as the cell voltage and coulombic charge in CV were in the order of magnitude: CL-SPEEK/MoPA40 (wt%) > CL-SPEEK/TPA30 > Nafion117. In the optimum cell applications for water electrolysis, the cell voltage of Pt/CL-SPEEK-MoPA40/Pt-Co (Dep-MoPA) and Pt/CL-SPEEK-TPA30/Pt-Co (Dep-TPA) was 1.75 Vat $80^{\circ}C$ and $1\;A/cm^2$ and voltage efficiency was 87.1%. Also, the observed activity of Pt-Co (84:16 atomic ratio by EDX) is a little higher than that of Pt-Ni (86: 14). The current density peak of electrodeposited electrodes were better a little than those of unactivated electrodes based on the same membranes.