• 제목/요약/키워드: supported metal

검색결과 359건 처리시간 0.026초

금속 나노 촉매를 활용한 선택적 알코올 산화 반응 (Supported Metal Nanoparticles: Their Catalytic Applications to Selective Alcohol Oxidation)

  • 무하마드 아시프 후세인;느얀즈 조셉;강온유;조용훈;엄병헌;김정원
    • 공업화학
    • /
    • 제27권3호
    • /
    • pp.227-238
    • /
    • 2016
  • 본 리뷰 논문은 지지화된 또는 고정화된 금속들 중 선택적 알코올 산화 반응에 적용된 나노 크기의 여러 금속 촉매들에 대해 집중적으로 서술한다. 금속 나노 촉매들은 넓은 표면적을 지닌 고체 지지체들의 표면 위에 금속 나노 입자들의 고른 분산을 통해 얻어진다. 이러한 나노 촉매들은 유기 합성, 연료 전지, 바이오 디젤 생산, 오일 크래킹, 에너지변환 및 저장, 의약, 수처리, 고체 로켓 추진체, 염료 제조 등 학문적 산업적 측면 모두 다양하게 사용될 수 있다. 더욱이, 응용성이 풍부한 중간체들을 생산하는 호기성 알코올 산화 반응에서 금속 나노 재료는 촉매로써 매우 중요하다. 금, 팔라듐, 류테늄, 바나디움 등과 같은 지지화된 금속 나노 촉매들의 알코올 산화 반응은 기존의 화학 당량적 반응과 달리 비용을 경감시키고 부반응물들을 줄임으로써 경제적이고 친환경적이다. 뿐만 아니라, 상온에서 진행된 나노 촉매 알코올 산화 반응에 대해서도 소개된다.

활성탄에 담지된 귀금속 촉매를 이용한 셀룰로우스의 폴리올로의 전환 (Conversion of Cellulose into Polyols over Noble Metal Catalysts Supported on Activated Carbon)

  • 유수진;김샛별;김용태;박은덕
    • 청정기술
    • /
    • 제16권1호
    • /
    • pp.19-25
    • /
    • 2010
  • 결정성의 셀룰로우스를 수소분위기하에서 다양한 귀금속 촉매를 이용하여 폴리올로 전환시키는 연구를 수행하였다. 촉매는 단일 귀금속(Pt, Ru, Ir, Rh, Pd)을 활성탄에 습식함침법으로 담지시켜서 제조하였으며, Pt/$\gamma-Al_2O_3$와 Pt/H-mordenite를 비교촉매로 사용하였다. 생성물은 고압액체크로마토그래피로 분석하였다. 촉매는 질소흡착, X-선 회절법, 유도결합플라즈마분광법(ICP-AES), 수소-승원환원분석($H_2$-TPR), 그리고 일산화탄소 화학흡착을 통하여 분석하였다. 셀룰로우스의 전환율은 사용한 촉매와 연관관계가 낮은 것으로 나타났으며 활성탄에 담지된 귀금속 촉매중에서 Pt/AC가 높은 폴리올의 수득률에 바람직한 것으로 조사되었다.

고체산화물 연료전지를 위한 물성치 모델 및 단전지 해석 (Physical Property Models and Single Cells Analysis for Solid Oxide Fuel Cell)

  • 박준근;김선영;배중면
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
    • /
    • pp.379-381
    • /
    • 2009
  • The simulation model for metal-supported Solid Oxide Fuel Cell(SOFC) is developed in this study. Open circuit voltage is calculated using Nernst equation and Gibbs free energy is required by thermodynamic. The exchange current densities are compared with experimental results since exchange current density is most effective factor for the activation loss. Liu's study is used for the exchange current density of cathode, BSCF, and Koide's result is applied for the exchange current density of anode, Ni/YSZ. For the ohmic loss, ionic conductivity of YSZ is described from Kilner's mode and the data are compared with Wanzenberg's experimental data. Diffusivity is an important factor for the mass transfer through the porous medium. Both binary diffusion and Knudsen diffusion are considered as the diffusion mechanism. For validation, simulation results at this work are compared with our experimental results.

  • PDF

디에틸렌트리아민을 지지시킨 폴리스틸렌수지에 대한 전이금속이온의 흡착속도와 메카니즘 (Rates and Mechanism of Adsorption of Transition Metal Ions on Polystyrene Resins Supported Diethylenetriamine)

  • 김선덕;신윤열;김창수
    • 분석과학
    • /
    • 제12권6호
    • /
    • pp.465-471
    • /
    • 1999
  • 클로로메틸화폴리스틸렌에 디에틸렌트리아민을 선형과 집게형으로 지지시킨 수지를 합성하고 이 수지에 전이금속이 흡착되는 속도를 limited-bath법으로 측정하였다. 이 결과에서 확산계수, 활성화 엔트로피와 활성화 자유에너지를 구하였다. 속도론적 데이터에서 전이금속이 수지에 흡착되는 반응 과정의 속도결정단계는 확산과정임을 알 수 있었다.

  • PDF

Oxidation of Ethylbenzene Using Nickel Oxide Supported Metal Organic Framework Catalyst

  • Peng, Mei Mei;Jeon, Ung Jin;Ganesh, Mani;Aziz, Abidov;Vinodh, Rajangam;Palanichamy, Muthiahpillai;Jang, Hyun Tae
    • Bulletin of the Korean Chemical Society
    • /
    • 제35권11호
    • /
    • pp.3213-3218
    • /
    • 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.

텅스텐산화물/금속기판의 광전극 특성 (Photoelectrochamical characteristics of $WO_3$ on metal substrate for hydrogen production)

  • 고근호;;서선희;이동윤;이원재
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2011년도 추계학술대회 초록집
    • /
    • pp.99.2-99.2
    • /
    • 2011
  • Transparent conducting oxides (TCOs) supported on glass are widely used as substrates in PEC studies for photovoltaic hydrogen generation applications However, high sheet resistane ($10{\sim}15{\Omega}/cm^2$) and fragileness of glass-supported TCO substrates are the obstacles to produce the large area PEC cells. Such internal sheet resistance is detrimental to efficient collection of photogenerated majority charge carriers at the photoactive material and electrolyte interface. Moreover, these TCO substrates are very expensive and consume about 40~60% cost of the devices. Hence, a low sheet resistance of the substrate is a key point in improving the performance of PEC devices. Metallic substrates coated with a photoactive material would be a good choice for efficient charge collection. Such metal substrates based photanodes are best candidate for large-scale phtoelectrochemical water splitting for hydrogen generation. In this study, we report the enhanced PEC performance of $WO_3$ film on metal(chemical etched, bare) substrate. It is proposed that interface between $WO_3$ and the metal substrate is responsible for efficient charge transfer and demonstrated significant improvement in the photoelectrochmical performance. X-ray diffration and FESEM suduies reveled that $WO_3$ films are monoclinic, porous, polycrystalline with average grain size of ~50nm. Photocurrent of $WO_3$ prepared on metal substrates was measured in 0.5M $H_2SO_4$ electroyte under simulated $100mW/cm^2$ illumination.

  • PDF

마이크로파 조사에 따른 금속이 담지 된 활성탄의 특성 연구 (A Study on the Characteristics of Activated Carbons Supported Metal by Microwave Irradiation)

  • 김성욱;김정배;최성우
    • 한국환경과학회지
    • /
    • 제18권5호
    • /
    • pp.501-508
    • /
    • 2009
  • In this study, the characteristics of granular activated carbon (GAC) supported metal was investigated in an area influenced by flame discharge and temperature variation during irradiating microwave. The modified GAC was formulated by impregnating metal hydroxides of nickel (Ni/GAC), barium (Ba/GAC), copper (Cu/GAC), zinc (Zn/GAC), cobalt (Co/GAC) and lanthanum (La/GAC). Ba/GAC was selected as it showed lack of spark discharge and temperature increasing aspects. Comparison of adsorption and desorption amount of GAC and Ba/GAC showed that adsorption and desorption rate of the GAC were higher than those of Ba/GAC. The results show that the presence of barium can decrease adsorption/desorption rate because of plugging pore of GAC. Toluene regeneration rate of Ba/GAC was better than that of GAC due to barium loading. Finally, GAC with barium can be controled a rapid increasing temperature and spark discharge, increased the regeneration rate of toluene during desorption by irradiating microwave.

Polyol Process를 통한 PEM Fuel Cell용 Pt/C촉매 제조 (Preparation of Pt/C catalyst for PEM fuel cells using polyol process)

  • 오형석;김한성
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2006년도 추계학술대회
    • /
    • pp.443-446
    • /
    • 2006
  • Carbon-supported Platinum (Pt) is the potential electro-catalyst material for anodic and cathodic reactions in fuel cell. Catalytic activity of the metal strongly depends on the particle shape, size and distribution of the metal in the porous supportive network. Conventional preparation techniques based on wet impregnation and chemical reduction of the metal precursors often do not provide adequate control of particle size and shape. We have proposed a novel route for preparing nano sized Pt colloidal particles in solution by oxidation of ethylene glycol. These Pt nano particles were deposited on large surface area carbon support. The process of nano Pt colloid formation involves the oxidation of solvent ethylene glycol to mainly glycolic acid and the presence of its anion glycolate depends on the solution pH. In the process of colloidal Pt formation glycolate actsas stabilizer for the Pt colloidal particle and prevents the agglomeration of colloidal Pt particles. These mono disperse Pt particles in carbon support are found uniformly distributed in nearly spherical shape and the size distribution was narrow for both supported and unsupported metals. The average diameter of the Pt nano particle was controlled in the range off to 3 nm by optimizing reaction parameters. Transmission electron microscopy, CV and RRDE experiments were used to compliment the results.

  • PDF