• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1481-1486
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• 2013

Bifunctional Fe-SBA-15-$SO_3H$ mesoporous materials with different Si/Fe molar ratios (3, 5, and 7) have been synthesized via a simple direct hydrothermal method and characterized by XRD, $N_2$-adsorption/desorption, TG/DTG and FT-IR techniques, and used as solid acid catalysts in the esterification of lactic acid with methanol. XRD and $N_2$ sorption characterizations show successful iron doping within the mesoporous channels of SBA-15-$SO_3H$. The FT-IR and TG/DTG characterizations also reveal the presence of iron. With the incorporation of Fe ions into the SBA-15-$SO_3H$, the acid sites substantially increased because of the self-separated acidity of the hydrolysis of $Fe^{3+}$ solutions. However, in the Si/Fe = 3 molar ratio, the catalytic conversion decreased which is caused by the reduced cooperation effect between the acid pairs due to the weakened hydrogen bonds and collapse of the pore structure. This further suggests that the mesoporous structure decreases with the decrease in Si/Fe ratio.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.231-231
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• 2009

In this work, we prepared the Ni-loaded porous SBA-15 (SBA-15) by a depositionprecipitation (D-P) method, in order to enhance the hydrogen storage capacity. The structure and morphology of the Ni/SBA-15 were characterized by X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). The results showed that, at the Ni loading used at the DP times in the range of 0-120 min, SBA-15 preserved the well-ordered hexagonal porous arrangement. The textural properties of the Ni/SBA-15 were analyzed using N2 adsorption isotherms at 77 K. Specific surface area and mesopore volume of the samples were determined from the Brunauer-Emmett-Teller (BET) equation and Barrett-Joiner-Halenda (BJH) method, respectively. The hydrogen storage capacity of the Ni/SBA-15 was evaluated at 298 K/10 MPa. The hydrogen storage capacity of the Ni/SBA-15 was increased in accordance with Ni content. Consequently, it was found that the presence of Ni on mesoporous SBA-15 created hydrogen-favorable sites which enhanced the hydrogen storage capacity by spillover effect.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3009-3016
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• 2012

This study evaluated the use of iron-impregnated SBA-15 (Fe/SBA-15) as a catalyst for the oxidative degradation of persistent phenol analogues, such as 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and 2,4,6-trichlorophenol (2,4,6-TCP) in water. The oxidation reactions were carried out with reaction time, concentration of the phenols, amount of the catalysts, reaction temperature, pH of the reaction mixture as the process variables with or without using hydrogen peroxide as the oxidizing agent. The conversion achieved with Fe/SBA-15 at 353 K for 2-CP, 4-CP, 2-NP, 4-NP, 2,4,6-TCP was 80.2, 71.2, 53.1, 62.8, 77.3% in 5h with a reactant to $H_2O_2$ mole ratio of 1:1, and 85.7, 65.8, 61.9, 63.7, 78.1% in the absence of $H_2O_2$, respectively. The reactions followed pseudo first order kinetics. The leachability study indicated that the catalyst released very little iron into water and therefore, the possibility of secondary pollution is negligible.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3535-3541
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• 2014

Bisphenol A is considered as pollutant, because it is toxic and hazardous to living organisms even at very low concentrations. Biological oxidation used for removing this organic from waste water is not suitable and consequently application of catalytic wet oxidation has been considered as one of the best options for treating bisphenol A. We have developed Fe/SBA-15, Ni/SBA-15 and Fe-Ni/SBA-15 as heterogeneous catalysts using the advanced impregnation method for oxidation of bisphenol A in water. The catalysts were characterized with physico-chemical characterization methods such as, powder X-ray diffraction (PXRD), FT-IR measurements, N2 adsorption-desorption isotherm, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. This work illustrates activity of the catalysts for heterogeneous catalytic degradation reaction revealed with excellent conversion and recyclability. The degradation products identified were not persistent pollutants. GC-MS analysis identified the products: 2,4-hexadienedioic acid, 2,4-pentadienic acid and isopropanol or acetic acid. The leachability study indicated that the catalysts release very little metals to water. Therefore, the possibility of water contamination through metal leaching was almost negligible.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 1부
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• pp.495-499
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• 2010

The biocatalytic capture of $CO_2$, and its precipitationas $CaCO_3$, over bovine carbonic anhydrase (BCA) immobilized on a pore-expanded SBA-15 support was investigated. SBA-15 was synthesized using TMB as a pore expander, and the resulting porous silica was characterized by XRD, BET, IR, and FE-SEM analysis. BCA was immobilized on SBA-15 through various approaches, including covalent attachment (BCA-CA), adsorption (BCA-ADS), and cross-linked enzyme aggregation (BCA-CLEA). The immobilization of BCA on SBA-15 was confirmed by the presence of zinc metal in the EDXS analysis. The effects of pH, temperature, storage stability, and reusability on the biocatalytic performance of BCA were characterized by examining para-nitrophenyl acetate (p-NPA) hydrolysis. The $K_{cat}/K_m$ values for p-NPA hydrolysis were 740.05, 660.62, and $680.11M^{-1}s^{-1}$, respectively, where as $K_{cat}/K_m$ for free BCA was $873.76M^{-1}s^{-1}$. The amount of $CaCO_3$ precipitate was measured quantitatively using anion-selective electrode and was found to be 12.41, 11.82, or 11.28 mg $CaCO_3$/mg for BCA-CLEA, BCA-ADS, or BCA-CA, respectively. The present results indicate that the immobilized BCA-CLEA, BCA-ADS, and BCA-CA are green materials, and are tunable, reusable, and promising biocatalysts for $CO_2$ sequestration.

• 공업화학
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• 제26권5호
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• pp.543-548
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• 2015

리튬이온 전지용 음극소재의 용량 및 사이클 성능을 향상시키기 위해서 Si/C/CNF 합성물의 특성이 조사되었다. 제조과정으로는 SBA-15를 합성하고 볼밀링을 이용한 마그네슘환원을 통해 Si/MgO를 얻은 다음, Phenolic resin과 CNF를 이용해 탄화과정을 거쳐 최종적으로 산처리하여 Si/C/CNF 활물질을 합성하였다. 합성된 Si/C/CNF는 BET, XRD, FE-SEM 그리고 TGA를 이용하여 분석하였다. $50^{\circ}C{\sim}70^{\circ}C$까지 온도에 따라 SBA-15를 합성한 결과 $60^{\circ}C$에서 가장 큰 비표면적을 갖는 결과를 얻었다. 또한 LiPF6 (EC : DMC : EMC = 1 : 1 : 1 vol%) 전해질을 사용하여, 충방전, 사이클, CV와 임피던스 등과 같은 전기화학적 테스트를 수행하여 Si/C/CNF 전극의 이차전지 음극활물질로서 성능을 조사하였다. Si/C/CNF (Si : CNF = 97 : 3 중량비)를 이용한 전지의 용량은 1,947 mAh/g으로 다른 합성물보다 우수한 결과를 보였다. CNF 첨가량이 3 wt%에서 11 wt%로 증가함에 따라 용량 보존율이 84~77%로 안정성이 감소되었다. Si/C/CNF 합성소재 전극이 이차전지의 사이클 성능과 전기전도도를 개선할 수 있다는 것을 알 수 있었다.

• 공업화학
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• 제27권2호
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• pp.190-194
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• 2016

Tricyclopentadiene (TCPD)는 차세대 고밀도에너지 연료인 tetrahydrotricyclopentadiene의 전구체로서 중요한 화합물이다. 본 연구에서는 이온성 액체가 담지된 메조포로스 실리카 촉매를 이용하여 dicyclopentadiene 소중합 반응을 통한 TCPD 합성에 관한 연구를 수행하였다. 나노기공의 크기가 다른 대표적인 메조포로스 실리카인 MCM-41과 SBA-15에 이온성 액체(IL)를 함침법을 이용하여 담지하고 소중합 촉매를 제조하였다. 음이온 전구체로 copper(I) chloride (CuCl) 또는 iron(III) chloride ($FeCl_3$), 양이온 전구체로 triethylamine hydrochloride (TEAC) 또는 1-butyl-3-methylimidazolium chloride(BMIC)를 사용하여 4가지 종류의 IL을 메조포로스 실리카에 담지하였다. 이온성 액체가 담지된 메조기공의 실리카를 사용하였을 때 이온성 액체만 사용하였을 때보다 TCPD 수율과 dicyclopentadiene (DCPD)의 전환율 측면에서 우수하였다. 특히, MCM-41에 루이스 산도가 낮은 CuCl계 이온성 액체를 담지할 때 TCPD 수율이 가장 높았다.

• Journal of Electrochemical Science and Technology
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• 제12권1호
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• pp.137-145
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• 2021

Among the non-precious metal catalysts, iron-nitrogen doped carbon (Fe-N/C) catalysts have been recognized as the most promising candidates for an alternative to Pt-based catalysts for the oxygen reduction reaction (ORR) under alkaline and acidic conditions. In this study, the nano replication method using mesoporous silica, which features tunable primary particle sizes and shape, is employed to prepare the mesoporous Fe-N/C catalysts with different shapes. Platelet SBA-15, irregular KIT-6, and spherical silica particle (SSP) were selected as a template to generate three different kinds of shapes of the mesoporous Fe-N/C catalyst. Physicochemical properties of mesoporous Fe-N/C catalysts are characterized by using small-angle X-ray diffraction, nitrogen adsorption-desorption isotherms, and scanning electron microscopy images. According to the electrochemical evaluation, there is no morphological preference of mesoporous Fe-N/C catalysts toward the ORR activity with half-cell configuration under alkaline electrolyte. By implementing X-ray photoelectron spectroscopy analysis of Fe and N atoms in the mesoporous Fe-N/C catalysts, it is possible to verify that the activity towards ORR highly depends on the portions of "Fe-N" species in the catalysts regardless of the shape of catalysts. It was suggested that active site distribution in the Fe-N/C is one important factor towards ORR activity.