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개미산 분해 반응에서 수소 생산성 증대를 위한 Pd/Pd<sub>3</sub>Fe 합금 촉매: 범밀도 함수 이론 연구
조진원 ( Jinwon Cho ),한종희 ( Jonghee Han ),윤성필 ( Sung Pil Yoon ),남석우 ( Suk Woo Nam ),함형철 ( Hyung Chul Ham ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.2
본 연구에서는 양자 역학 계산 이론 중 하나인 Density Functional Theory (DFT)를 사용하여 Pd/Pd<sub>3</sub>Fe 촉매 표면에서 개미산(HCOOH) 분해 반응으로부터 수소를 생산하는 반응 메커니즘을 분석하였다. 기존 연구에 따르면, 단일 원자 촉매 중에서 개미산 분해 반응에 가장 높은 수소 생산성을 기록하는 원자는 Pd 촉매이지만, 부 반응으로 생산되는 CO가 Pd에 독성을 띄우기 때문에 Pd 촉매의 성능을 저하시킨다. 이러한 단점을 극복하고자, Pd를 기반으로 Pd와 Fe를 3:1로 합금하여 Pd<sub>3</sub>Fe가 코어(core) 형태로 존재하고 Pd가 표면에 위치한 core-shell Pd/Pd<sub>3</sub>Fe 촉매를 설계하여 개미산 분해 반응에 의한 수소 생산 속도를 계산하였다. 순수 Pd촉매 보다 Pd/Pd<sub>3</sub>Fe 촉매의 수소 생산 반응의 활성 에너지가 감소 하였다. 그 이유는 Pd와 Fe가 합금화 되면서 Pd<sub>3</sub>Fe의 격자 상수가 2.76 A로 줄어 들어 HCOO의 흡착에너지를 0.03 eV 감소시켰고, Fe에서 표면 Pd로 전자가 이동하면서 표면 전자 구조가 변화하여 HCOO의 흡착에너지를 0.29 eV 낮추었기 때문이다. 본 연구에서 제안하는 결과를 바탕으로 추후 개미산으로부터 수소 생산이 더 용이한 새로운 촉매 설계 메커니즘을 제안하고자 한다. Formic acid has been known as one of key sources of hydrogen. Among various monometallic catalysts, hydrogen can be efficiently produced on Pd catalyst. However, the catalytic activity of Pd is gradually reduced by the blocking of active sites by CO, which is formed from the unwanted indirect oxidation of formic acid. One of promising solutions to overcome such issue is the design of alloy catalyst by adding other metal into Pd since alloying effect (such as ligand and strain effect) can increase the chance to mitigate CO poisoning issue. In this study, we have investigated formic acid deposition on the bimetallic Pd/Pd<sub>3</sub>Fe core-shell nanocatalyst using DFT (density functional theory) calculation. In comparison to Pd catalyst, the activation energy of formic acid dehydrogenation is greatly reduced on Pd/Pd<sub>3</sub>Fe catalyst. In order to understand the importance of alloying effects in catalysis, we decoupled the strain effect from ligand effect. We found that both strain effect and ligand effect reduced the binding energy of HCOO by 0.03 eV and 0.29 eV, respectively, compared to the pure Pd case. Our DFT analysis of electronic structure suggested that such decrease of HCOO binding energy is related to the dramatic reduction of density of state near the fermi level.
Effect of Commingled Yarn Type on the Manufacturing of Glass Fiber/Polypropylene Composite Prepreg
Jinwon Cho(조진원),Jaehyeung Park(박재형) 한국고분자학회 2021 폴리머 Vol.45 No.3
본 연구에서는 다른 방식의 커밍글 얀(commingled yarn)과 제직방법을 이용하여 유리섬유와 폴리프로필렌 복합 프리프레그를 제조하고 그 구조 특성과 성질에 대해 살펴보았다. 복합 프레프레그 제조를 위하여 covering 방식과 air textured 방식으로 제조된 두 종류의 커밍글 얀을 이용하여, 평직과 능직으로 직조하였다. 프리프레그 제작 시 커밍글얀 방식과 직조방법에 따라 유리 섬유의 배열이 불규칙적으로 이동됨을 확인하였고, 이는 열가소성 수지인 폴리프로필렌의 높은 점도에 기인한 것이다. 직조된 유리섬유 패턴의 변형은 프리프레그의 기계적 물성에 큰 영향을 미치는 것을 확인하였다. 본 연구에서 확인된 결과들은 향후 하이브리드 섬유를 이용한 프리프레그 개발 시 공정을 설계하는데 도움이 될 것으로 기대된다. Glass fiber/polypropylene (GF/PP) composite prepregs were produced using different types of commingled yarns with different weave patterns. The commingled yarn used in this study was prepared using covering and air textured methods and the prepared commingled yarns were woven into two different weave patterns, plain and twill. The results show the effect of the commingling method and weave pattern on impregnation and alignment of GF in the composite prepregs due to the flow of the highly viscous molten PP resins. The mechanical properties (tensile strength, puncture impact properties, and Izod pendulum impact resistance) of the prepared composite prepregs were also evaluated. The results of this study show that the best tensile and impact resistance properties of composite prepreg is achieved using fabrics with a twill weave pattern made from air textured yarn (ATY) commingled yarns, which ensures the uniformity and alignments of the GF yarns in the composite.
생화학적 마커와 Microsatellite 마커를 이용한 KCR 랫드의 유전모니터링
박한진(Han-Jin Park),이철호(Chul-Ho Lee),차달선(Dal-Seon Cha),조재우(Jae-Woo Cho),조규혁(Kyu-Hyuk Cho),최양규(Yang-Kyu Choi),현병화(Byung-Hwa Hyun),조진원(Jin-Won Cho),한상섭(Sang-Seop Han),송창우(Chang-Woo Song) 한국실험동물학회 2004 Laboratory Animal Research Vol.20 No.2
The cataract mutant rat which showed lens opacity was found in the colony of Sprague-Dawley rat at Korea Research Institute of Chemical Technology (KRICT) in 1996. The mode of inheritance of affected rats was autosomal recessive. These cataractous rats were mated by sister and brother to 27th (F₂₇) generation and named as Korea Cataract Rat (KCR). We performed genetic monitoring of KCR rat using biochemical and microsatellite markers to determine their genetic identified homozygous and distinctive genetic profile. In biochemical monitoring, six rats from each of the F₁₈/F₁₉F₂₀ were tested using 13 biochemical markers. In molecular genetic monitoring, nine rats from the F₂₅ and F₂₆ were tested using 13 microsatellite markers. No differences were found among the genetic profiles of the F₁₈/F₁₉F₂₀ in biochemical monitoring. Also, in the molecular genetic monitoring, we identified that both genetic profiles of F₂₅ and F₂₆ were the same. The genetic profile of KCR rats was unique against the other major rat strains. In addition, the polymorphysm of KCR rat for microsatellite markers was different from the other strains. These results suggest that KCR rat is genetically well qualified as far as in this test and it has been well established as a new inbred strain which has a novel genetic profile and cataract trait.