Carbon materials with tailorable structures and superior properties have great potential applications in environmental protection, energy conversion, and catalysis. Plant biomass as abundant and green non-toxic raw materials has been considered as good precursors for synthesizing heteroatom-doped carbon materials. However, few studies have been reported on the different natures of carbon materials derived from different parts of the same plant biomass. In this study, we prepared carbon materials from the petioles and blades of apricot leaves by direct pyrolysis without additives. Detailed characterizations indicate that these two carbon materials are similar in element composition and graphitization degree, but differ greatly in surface area and pore volume. These differences can be attributed to the different contents of inorganic salts, vascular bundles, and proteins in petioles and blades. When used as catalysts for the oxidation of ethylbenzene, the petiole-derived carbon shows better catalytic performance than the blades derived carbon due to its high surface area, large average pore size, and doped nitrogen atoms. Furthermore, the carbon catalysts derived from the petioles and blades of poplar leaves and parasol tree leaves show the same difference in catalytic reaction, implying that the above-mentioned conclusion is rather universal, which can provide reference for the synthesis of carbon materials from leaves.

It is necessary to fabricate uniformly dispersed nanoscale catalyst materials with high activity and long-term stability for polymer electrolyte membrane fuel cells with excellent electrochemical characteristics of the oxygen reduction reaction and hydrogen oxidation reaction. Platinum is known as the best noble metal catalyst for polymer electrolyte membrane fuel cells because of its excellent catalytic activity. However, given that Pt is expensive, considerable efforts have been made to reduce the amount of Pt loading for both anode and cathode catalysts. Meanwhile, the atomic layer deposition (ALD) method shows excellent uniformity and precise particle size controllability over the three-dimensional structure. The research progress on noble metal ALD, such as Pt, Ru, Pd, and various metal alloys, is presented in this review. ALD technology enables the development of polymer electrolyte membrane fuel cells with excellent reactivity and durability.

We have studied a method to prepare polydopamine-modified reduced graphene oxide-supported Pt nanoparticles (Pt– PDA–RGO). The Pt–PDA–RGO nanocomposites were synthesized by a wet-coating process, which was induced by selfpolymerization of dopamine. As an eco-friendly and versatile adhesive source in nature, dopamine could be easily adhered to surfaces of organic material and inorganic material via polymerization processes and spontaneous adsorption under weak alkaline pH conditions. To apply the unique features of dopamine, we synthesized Pt–PDA–RGO nanocomposites with a different quantity of dopamine, which are expected to preserve the improved Pt adsorption on graphene, resulting in the enhanced electrocatalytic performance. The morphology and micro-structure were examined by field emission scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Compared to pristine Pt–deposited RGO (Pt–RGO), Pt–PDA–RGO (30 wt% dopamine against RGO) nanocomposites showed a superior electrochemical active surface area for a methanol oxidation. This could be related to the fact that the optimized c

The present polymer have a conjugated polymer backbone system with the designed substituents. The photoluminescence peak of polymer was observed at 525nm, which is corresponded to the photon energy of 2.36 eV and the band gap of poly(EBA) was 2.38 eV. The cyclovoltamograms of the polymer exhibited the irreversible electrochemical behaviors. It was found that the kinetics of the redox process of this conjugated polymer might be mainly controlled by the diffusion process from the experiment of the oxidation current density of polymer versus the scan rate.

Nitrogen (N)-doped protein-based carbon as platinum (Pt) catalyst supports from tofu for oxygen reduction reactions are synthesized using a carbonization and reduction method. We successfully prepare 5 wt% Pt@N-doped protein-based carbon, 10 wt% Pt@N-doped protein-based carbon, and 20 wt% Pt@N-doped protein-based carbon. The morphology and structure of the samples are characterized by field emission scanning electron microscopy and transmission electron micro scopy, and crystllinities and chemical bonding are identified using X-ray diffraction and X-ray photoelectron spectroscopy. The oxygen reduction reaction are measured using a linear sweep voltammogram and cyclic voltammetry. Among the samples, 10 wt% Pt@N-doped protein-based carbon exhibits exellent electrochemical performance with a high onset potential of 0.62 V, a high E1/2 of 0.55 V, and a low ΔE1/2= 0.32 mV. Specifically, as compared to the commercial Pt/C, the 10 wt% Pt@N-doped proteinbased carbon had a similar oxygen reduction reaction perfomance and improved electrochemical stability.

Activated carbon (AC) was modified by ammonium persulphate or nitric acid, respectively. AC and the modified materials were used as catalyst supports. The oxygen groups were introduced in the supports during the modifications. All the supports were characterized by N2-physisorption, Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and thermogravimetric analysis. Methanol synthesis catalysts were prepared through wet impregnation of copper nitrate and zinc nitrate on the supports followed by thermal decomposition. These catalysts were measured by the means of N2-physisorption, X-ray diffraction, XPS, temperature programmed reduction and TEM tests. The catalytic performances of the prepared catalysts were compared with a commercial catalyst (CZA) in this work. The results showed that the methanol production rate of AC-CZ (23 mmol- CH3OH/(g-Cu·h)) was higher, on Cu loading basis, than that of CZA (9 mmol-CH3OH/ (g-Cu·h)). We also found that the modification methods produced strong metal-support interactions leading to poor catalytic performance. AC without any modification can prompt the catalytic performance of the resulted catalyst.

본 연구는 폴리에틸렌 중합에 이용되는 Ziegler-Natta 촉매와는 다른 Indene및 Cyclopent adien을 기반으로 하는 다양한 메탈로센 촉매를 사용하여 폴리에틸렌 왁스를 중합하고 중합한 폴리에틸렌 왁스 의 특성에 대해 분석하고 평가하였다. 폴리에틸렌 왁스 중합은 각 다른 구조의 리간드를 포함하는 메탈로 센 촉매에 대하여 중합온도, 연쇄이동제로 사용되는 수소와 에틸렌가스의 비율을 조정하여 다양한 조건하에서 중합을 시도 하였으며 그에 따른 분자량과 분자량 분포, 촉매 수율을 비교 분석하였다. 결과적으로 본 연구를 통하여 저분자량을 가지며 좁은 분자량 분포를 가지기에 적합한 메탈로센 촉매의 구조를 제안하였으며 이상적인 폴리에틸렌 왁스를 중합 할 수 있었다.

Well-dispersed platinum catalysts on ruthenium oxide nanofiber supports are fabricated using electrospinning, post-calcination, and reduction methods. To obtain the well-dispersed platinum catalysts, the surface of the nanofiber supports is modified using post-calcination. The structures, morphologies, crystal structures, chemical bonding energies, and electrochemical performance of the catalysts are investigated. The optimized catalysts show well-dispersed platinum nanoparticles (1-2 nm) on the nanofiber supports as well as a uniform network structure. In particular, the well-dispersed platinum catalysts on the ruthenium oxide nanofiber supports display excellent catalytic activity for oxygen reduction reactions with a half-wave potential (E1/2) of 0.57 V and outstanding long-term stability after 2000 cycles, resulting in a lower E1/2 potential degradation of 19 mV. The enhanced electrochemical performance for oxygen reduction reactions results from the well-dispersed platinum catalysts and unique nanofiber supports.

본 연구는 메탈로센 촉매를 이용한 폴리에틸렌 왁스의 중합과 그 특성에 관한 연구를 진행 하였다.폴리에틸렌 왁스 중합에 사용되는 다양한 중합 조건을 시도하였다. 낮은 분자량을 갖는 폴리에틸 렌 중합에 널리 이용되는 Ziegler-Natta 촉매와는 다른 여러가지 구조의 리간드를 갖는 다양한 메탈로 센 촉매가 중합 특성에 미치는 영향에 대한 연구와 촉매의 수소 반응성에 관한 연구를 진행하였다. 또 한 연쇄이동제인 수소량에 따른 분자량의 변화와 에틸렌 가스의 비율에 따른 분배를 관찰하였다. 마지막 으로 본 연구에서는 폴리에틸렌 왁스의 중합에 적합한 메탈로센 촉매 구조를 제안하였다.

본 연구는 폴리스타렌(PS) 수지의 유화공정 효율성 향상을 위해 저온열분해 회분식 반응기를 이용하여, 단일 PS 수지와 Co 및 Mo 촉매를 각각 첨가한 PS 수지를 반응온도(425, 450, 475℃), 반응 시간(20~80분, 15분 간격), 촉매 농도변화에 따른 PS수지의 액화생성물 전환율을 측정하였다. 최적의 열분해 조건은 반응온도 450℃, 반응시간 35분으로 판단되며, 전환된 액화생성물의 주요 성분은 GC/MS 분석결과 스타이렌 및 벤젠유도체가 대부분으로 나타났다. 생성물은 산업통상자원부에서 고시 한 증류성상 온도에 따라 가스, 가솔린, 등유, 경유, 중유로 분류하여 그 수율을 측정하였다. 그리고 45 0℃ 반응온도에서 촉매 사용에 따른 전환율은 Co 촉매 > Mo 촉매 > 무촉매 순이었으며, 생성물 중 가 스, 등유, 경유수율은 Mo 촉매, 가솔린은 무촉매, 중유는 Co 촉매에서 우수한 것으로 나타났다. Co 및 Mo 촉매 혼합 농도별 전환율 및 열분해 생성물 수율은 Co 촉매 100% 사용 시 가장 우수한 것으로 판 단된다.

Flower-like nickel oxide (NiO) catalysts were coated on NiCrAl alloy foam using a hydrothermal method. The structural, morphological, and chemical bonding properties of the NiO catalysts coated on the NiCrAl alloy foam were investigated by field-emission scanning electron microscopy, scanning electron microscopy-energy dispersive spectroscopy, Xray diffraction, and X-ray photoelectron spectroscopy, respectively. To obtain flower-like morphology of NiO catalysts on the NiCrAl alloy foam, we prepared three different levels of pH of the hydrothermal solution: pH-7.0, pH-10.0, and pH-11.5. The NiO morphology of the pH-7.0 and pH-10.0 samples exhibited a large size plate owing to the slow reaction of the hydroxide (OH−) and nickel ions (Ni+) in lower pH than pH-11.5. Flower-like NiO catalysts (~4.7 μm-6.6 μm) were formed owing to the fast reaction of OH− and Ni2+ by increased OH− concentration at high pH. Thus, the flower-like morphology of NiO catalysts on NiCrAl alloy foam depends strongly on the pH of the hydrothermal solution.

금속 산화물과 혼합한 Pt-Sn/Al2O3 촉매의 프로판 탈수소 반응 성능의 향상 가능성에 대해 서 연구하였다. 금속 산화물로서 Cu-Mn/γ-Al2O3, Ni-Mn/γ-Al2O3, Cu/α-Al2O3를 제조하여 Pt-Sn/Al2O3 촉매와 혼합하고, 프로판 탈수소 반응 성능을 측정하였다. 이 결과들을 불활성 물질인 glass bead를 혼합한 Pt-Sn/Al2O3 촉매를 기준샘플로 삼아 비교하였다. 촉매와 금속산화물을 환원처리 하지 않고 반응 실험한 경우, 576.5℃에서 기준샘플의 전환율 8% 대비, Cu-Mn/γ-Al2O3를 혼합한 Pt-Sn/Al2O3 촉매가 14.9%의 높은 전환율과 96.8%의 선택도를 보였다. 촉매와 금속산화물을 환원 처 리하여 반응활성을 측정한 경우, Cu/α-Al2O3과 Pt-Sn/Al2O3의 혼합촉매가 기준샘플대비 초기에 높은 수율을 보였다. 그러나, 촉매를 환원 처리한 경우 전반적으로 전환율 상승이 크지 않았고, 이것으로 Cu-Mn/γ-Al2O3의 격자산소가 탈수소반응의 전환율 증가 영향을 주었음을 알 수 있었다.

Cu-Mn과 Cu-Zn 촉매를 침전제로 다르게 하거나, 금속의 몰비율, 소성온도를 다르게 하여 공침법으로 제조하였고 CO산화반응을 수행하여 혼합산화물 촉매에서 Cu, Mn과 Zn의 영향 및 소성온 도가 미치는 영향을 조사하였다. 촉매의 물리·화학적 특성을 알아보기 위하여 XRD, N2 흡착 및 SEM 의 분석을 수행하였다. Na2CO3로 침전시켜 270℃로 소성하여 제조한 2Cu-1Mn 산화물 촉매가 저온에 서 CO 산화반응 활성이 가장 좋았으며 2Cu-1Mn 산화물 촉매는 43 m2/g으로 가장 높은 비표면적과 촉매 활성을 나타내었다. XRD로 촉매의 결정구조를 분석하였을 때 Cu0.5Mn2.5O4의 결정구조를 갖는 촉 매는 낮은 활성을 보였다. 270℃에서 소성한 촉매가 좋은 활성을 나타냈으며 Pt 촉매와 비교하여도 저 온에서 CO산화반응이 더욱 우수함을 알 수 있었다.

Pt@Cu/C core-shell catalysts were successfully prepared by impregnation of a carbon support with copper precursor, followed by transmetallation between platinum and copper. The Pt@Cu/C core-shell catalysts retained a core of copper with a platinum surface. The prepared catalysts were used for hydrogen production through catalytic dehydrogenation of decalin for eventual application to an onboard hydrogen supply system. Pt@Cu/C core-shell catalysts were more efficient at producing hydrogen via decalin dehydrogenation than Pt/C catalysts containing the same amount of platinum. Supported coreshell catalysts utilized platinum highly efficiently, and accordingly, are lower-cost than existing platinum catalysts. The combination of impregnation and transmetallation is a promising approach for preparation of Pt@Cu/C core-shell catalysts.

NiO catalysts/Al2O3/FeCrAl alloy foam for hydrogen production was prepared using atomic layer deposition (ALD)and subsequent dip-coating methods. FeCrAl alloy foam and Al2O3 inter-layer were used as catalyst supports. To improve thedispersion and stability of NiO catalysts, an Al2O3 inter-layer was introduced and their thickness was systematically controlledto 0, 20, 50 and 80nm using an ALD technique. The structural, chemical bonding and morphological properties (includingdispersion) of the NiO catalysts/Al2O3/FeCrAl alloy foam were characterized by X-ray diffraction, X-ray photoelectronspectroscopy, field-emission scanning electron microscopy and scanning electron microscopy-energy dispersive spectroscopy. Inparticular, to evaluate the stability of the NiO catalysts grown on Al2O3/FeCrAl alloy foam, chronoamperometry tests wereperformed and then the ingredient amounts of electrolytes were analyzed via inductively coupled plasma spectrometer. We foundthat the introduction of Al2O3 inter-layer improved the dispersion and stability of the NiO catalysts on the supports. Thus, whenan Al2O3 inter-layer with a 80nm thickness was grown between the FeCrAl alloy foam and the NiO catalysts, it indicatedimproved dispersion and stability of the NiO catalysts compared to the other samples. The performance improvement can beexplained by optimum thickness of Al2O3 inter-layer resulting from the role of a passivation layer.

Carbon-supported Pt catalyst systems containing defect adsorption sites on the anode of direct methanol fuel cells were investigated, to elucidate the mechanisms of H2 dissociation and carbon monoxide (CO) poisoning. Density functional theory calculations were carried out to determine the effect of defect sites located neighboring to or distant from the Pt catalyst on H2 and CO adsorption properties, based on electronic properties such as adsorption energy and electronic band gap. Interestingly, the presence of neighboring defect sites led to a reduction of H2 dissociation and CO poisoning due to atomic Pt filling the defect sites. At distant sites, H2 dissociation was active on Pt, but CO filled the defect sites to form carbon π-π bonds, thus enhancing the oxidation of the carbon surface. It should be noted that defect sites can cause CO poisoning, thereby deactivating the anode gradually.