• 한국분말재료학회지
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• 제18권6호
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• pp.538-545
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• 2011

This study shows that catalytic activity of bimetallic RhPt nanoparticle arrays under CO oxidation can be tuned by varying the size and composition of nanoparticles. The tuning of size of RhPt nanoparticles was achieved by changing concentration of rhodium and platinum precursors in one-step polyol synthesis. Two-dimensional RhPt bimetallic nanoparticle arrays in different size and composition were prepared through Langmuir-Blodgett thin film technique. CO oxidation was carried out on these two-dimensional nanoparticle arrays, revealing higher activity on the smaller nanoparticles compared to the bigger nanoparticles. X-ray photoelectron spectroscopy (XPS) results indicate the preferential surface segregation of Rh compared to Pt on the smaller nanoparticles, which is consistent with the thermodynamic analysis. Because the catalytic activity is associated with differences in the rates of $O_2$ dissociative adsorption between Pt and Rh, this paper suppose that the surface segregation of Rh on the smaller bimetallic nanoparticles is responsible for the higher catalytic activity in CO oxidation. This result suggests a control mechanism of catalytic activity via synthetic approaches of colloid nanoparticles, with possible application in rational design of nanocatalysts.

• 폴리머
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• 제24권2호
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• pp.252-258
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• 2000

4-비닐피리딘과 N,N'-1,6-헥사메틸렌비스아크릴아미드를 라디칼중합하여 여러 가지 가교도를 가지는 가교 폴리(4-비닐피리딘) (CHP4VP)을 합성하였고, 이들 가교고분자와 구리(II)와의 착물을 평형흡착법으로 제조하였다. 제조한 착물들을 ascorbic acid (AA)의 산화반응 촉매로 사용하여 촉매활성을 조사하였다. CHP4VP-Cu(II) 착물에 의한 AA 산화반응은 Michaelis-Menten형 동력학적 거동을 나타내었다. CHP4VP-Cu(II) 촉매계의 촉매활성은 CHP4VP의 가교도가 증가할수록 증가하였고, 또 CHP4VP-Cu(II) 착물은 재사용 후에도 촉매활성이 거의 감소하지 않았다. 그러나 CHP4VP-Cu(II) 착물은 전보의 N,N'-메틸렌비스아크릴아미드가 가교제로 포함된 가교 폴리(4-비닐피리딘)-구리(II) 착물보다 AA 산화반응에 대한 촉매활성이 감소하는 경향을 나타내었다. 이들 결과로 부터 촉매계에 포함된 CHP4VP의 가교도와 가교제의 소수성이 AA 산화반응에 중요한 역할을 함을 알 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.304-304
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• 2010

The study on the catalytic oxidation of carbon monoxide (CO) to carbon dioxide ($CO_2$) using the noble metals has long been the interest subject and the recent progress in nanoscience provides the opportunity to develop new model systems of catalysts in this field. Of the noble metal catalysts, we selected ruthenium (Ru) as metal catalyst due to its unusual catalytic behavior. The size of colloid Ru NPs was controlled by the concentration of Ru precursor and the final reduction temperatures. For catalytic activity of CO oxidation, it was found that the trend is dependent on the size of Ru NPs. In order to explain this trend, the surface oxide layer surrounding the metal core has been suggested as the catalytically active species through several studies. In this poster, we show the influence of surface oxide on Ru NPs on the catalytic activity of CO oxidation using chemical treatments including oxidation, reduction and UV-Ozone surface treatment. The changes occurring to UV-Ozone surface treatment will be characterized with XPS and SEM. The catalytic activity before and after the chemical modification were measured. We discuss the trend of catalytic activity in light of the formation of core-shell type oxide on nanoparticles surfaces.

• 한국응용과학기술학회지
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• 제33권1호
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• pp.100-109
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• 2016

본 연구에서는 촉매 상 $H_2O_2$ 전환에 의해 건식산화제가 생성되었으며, 이를 이용한 NO 산화 공정에 대한 연구를 진행하였다. 건식산화제를 생성하기 위한 $H_2O_2$ 촉매 전환에 관한 실험을 수행한 결과, Mn계 촉매의 성능이 가장 우수하였으며, 이를 통해 생성된 건식산화제를 NO 산화공정에 주입하여 다양한 운전조건에서 NO 산화특성을 조사하였다. 그 결과, $H_2O_2$ 주입량, 산화반응온도, 그리고 공간속도가 NO 산화율에 크게 영향을 미치는 것을 확인하였다. 그리고, 산화반응온도와 $H_2O_2$ 주입량이 증가할수록 NO 산화효율이 증가하였으며, 공간속도가 증가할수록 NO 산화효율이 감소하였다.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.151-156
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• 2010

In this paper, we characterized bimetallic Pt-Ru/C alloy catalysts having four different compositions and compared the catalytic activities of the prepared alloys for CO oxidation. ICP-AES, EDS, XRD, TEM, and XAS were used to investigate the composition, degree of alloying, particle size, and electronic structure of the prepared Pt-Ru/C catalysts. Those results indicated the synthesis of the alloy catalysts with intended composition and uniform size. The electrochemical study of the characterized alloys showed higher catalytic activity for CO oxidation than that of the commercial Pt/C (E-TEK, Inc., 20 wt %) catalyst. Especially, it was shown that the alloy catalyst with Ru composition of 50 atomic % gave the highest catalytic activity for CO oxidation.

• 공업화학
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• 제25권3호
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• pp.237-241
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• 2014

벤젠은 발암성을 가진 유해성 대기 오염물질로 특별한 관리가 필요하다. 특히 벤젠은 실외 뿐만 아니라 실내에서도 존재하기 때문에 실내외를 구분하여 적절한 처리 방법이 요구된다. 실외의 공정에서 배출되는 VOC는 촉매 산화법을 통하여 $300-400^{\circ}C$에서 제거하는 것이 바람직하지만, 실내의 경우는 $100^{\circ}C$ 이하 혹은 실온에서 제거되는 것이 바람직하다. 본 총설은 촉매산화법, 촉매오존산화법 등 다양한 촉매 벤젠 산화법의 최근 동향을 다루고 있으며, 특히 저온산화반응을 위해 Mn 기반 촉매에 중점을 두고 조사하였다. Mn 기반 촉매는 다른 귀금속 촉매에 비하여 경제적으로 매우 이로우며, 특히 다양한 제조법을 적용하여 보다 효율적인 Mn 기반 벤젠 제거 촉매가 개발되고 있다. 또한 오존을 이용하여 $100^{\circ}C$ 이하, 특히 상온에서도 효율적으로 벤젠을 제거할 수 있기 때문에, Mn 기반 촉매의 효율성은 더욱더 증가할 것으로 판단된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.213-213
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• 2011

Gold catalysts supported on TiO2 have shown a unique catalytic behavior on CO oxidation, depending on surface effects. Particle size has an influence on the surface activity. To make monodisperse Au nanoparticles, organic capping ligands, such as alkylthiols, were used by a "greener" synthesis method [1,2] and Au nanoparticles were deposited on TiO2. However, organic capping ligands must be removed for high catalytic activities by the Au nanoparticles without changing the Au size [3]. We used UV ozone treatment to decompose thiol ligands. The samples have been characterized by X-ray photoelectron spectroscopy to examine the surface modification by UV ozone treatment. We show the size distribution of the gold nanoparticles by light scattering analysis and transmission electron microscopy. Au/TiO2 have been prepared using the wetness impregnation method. The catalytic performance of CO oxidation over Au supported on TiO2 under oxidizing reaction conditions (40 Torr CO and 100 Torr O2) were tested. The results show that the catalytic activity depends on particle size and the time of UV ozone exposure, which suggests the role of sulfur bonding in determining the catalytic activity of Au/TiO2 catalysts.

• 대한화학회지
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• 제57권3호
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• pp.322-328
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• 2013

Copper iodide was employed as a modifier for preparation of a new carbon ceramic electrode. For the first time, the catalytic oxidation of amoxicillin (AMX) was demonstrated by cyclic voltammetry, chronoamperometry and amperometry methods at the surface of this modified carbon ceramic electrode. The copper iodide modified sol-gel derived carbon ceramic (CIM-SGD-CC) electrode has very high catalytic ability for electrooxidation of amoxicillin. The catalytic oxidation peak current was linearly dependent on the amoxicillin concentration and the linearity range obtained was 100 to 1000 ${\mu}mol\;L^{-1}$ with a detection limit of 0.53 ${\mu}mol\;L^{-1}$. The diffusion coefficient ($D=(1.67{\pm}0.102){\times}10^{-3}\;cm^2\;s^{-1}$), and the kinetic parameter such as the electron transfer coefficient (${\alpha}$) and exchange current density ($j_0$) for the modified electrode were calculated. The advantages of the modified CCE are its good stability and reproducibility of surface renewal by simple polishing, excellent catalytic activity and simplicity of preparation.

• 한국입자에어로졸학회지
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• 제4권2호
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• pp.51-67
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• 2008

In this study, we devoted to kinetic measurement of the catalytic oxidation of iron-containing flame soot particles and better understanding the role of catalytic particles on carbon oxidation in particular at low temperature, targeting on autothermal regeneration of diesel particulate filter by diesel exhaust gas. Carbon-based Fe-containing particles generated by spraying ferrocene-doped diesel fuel in an oxy-hydrogen flame are tested and compared with a commercial carbon black powder for thermogravimetric analysis (TGA), secondary ion mass spectrometry (SIMS), Fourier-transform infrared spectroscopy (FTIR), Induced coupled plasma-Atomic emission spectroscopy (ICP-AES), and High-resolution transmission electron microscopy (HR-TEM). As a result, we found that a small amount of the ferrocene addition led to significant reductions in a on-set temperature and an activation energy of the carbon oxidation as well. An oxygenated surface complex forming at the particle surface could be thought as active species that would be readily consumed in particular at low temperature.

• 한국환경과학회지
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• 제18권4호
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• pp.445-450
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• 2009

In this study, the fundamental experiments were performed for catalytic oxidation of NO (50 ppm) on $MnO_2$ in the presence of ozone. The experiments were carried out at various catalytic temperatures ($30-120^{\circ}C$) and ozone concentrations (50-150 ppm) to investigate the behavior of NO oxidation. The honeycomb type $MnO_2$ catalyst was rectangular with a cell density of 300 cells per square inch. Due to $O_3$ injection, NO reacted with $O_3$ to form $NO_2$, which was adsorbed at the $MnO_2$ surface. The excessive ozone was decomposed to $O^*$ onto the $MnO_2$ catalyst bed, and then that $O^*$ was reacted with $NO_2$ to form $NO_3^-$. It was found that the optimal $O_3$/NO ratio for catalytic oxidation of NO on $MnO_2$ was 2.0, and the NO removal efficiency on $MnO_2$ was 83% at $30^{\circ}C$. As a result, NO was converted mainly to $NO_3^-$.