검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 169

        3.
        2025.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research developed a highly efficient voltammetric sensor, utilizing a carbon paste electrode (CPE) integrated with a novel ZnO-doped Pd–Pt bimetallic catalyst decorated with reduced graphene oxide (ZnO-Pt@Pd/rGO) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIM][Tf2N]), for the precise determination of sulfafurazole in real dextrose saline and tablet samples. The ZnO-Pt@Pd/rGO nanocomposite was synthesized through a one-stage synthesis process and characterized using SEM and EDS techniques. The comparison of the ZnO-Pt@Pd/rGO/[EMIM][Tf2N]/CPE with unmodified CPE, ZnO-Pt@Pd/rGO/CPE, and [EMIM][Tf2N]/CPE confirms the synergic effect of ZnO-Pt@Pd/rGO and [EMIM][Tf2N] as two conductive catalysts in fabrication of new sensor. The resulting sensor exhibited remarkable stability over a period of 2 months without compromising its efficiency for sulfafurazole detection. With a linear range of 0.001–250 μM (R2 = 0.9971) and LOD of 0.4 nM, ZnO-Pt@Pd/rGO/[EMIM][Tf2N]/CPE showcased exceptional accuracy and precision in the monitoring of sulfafurazole. Validation using real tablet and dextrose saline samples confirmed the sensor's outstanding capability in determining sulfafurazole, with relative recoveries ranging from 98.92 to 103.8% offering a promising solution for reliable sulfafurazole analysis in diverse pharmaceutical samples.
        4,000원
        5.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study introduces a novel method for synthesizing carbon nanotube (CNT) fibers using floating catalyst chemical vapor deposition (FC-CVD) in an open-atmosphere without the need for hydrogen as a carrier gas. Traditional FC-CVD techniques depend on hydrogen gas and require a harvest box with inert gas purging, which restricts scalability. Our approach utilizes nitrogen gas as the sole carrier, allowing for CNT fiber production without a harvest box. To understand the spinning process mechanism in an open-atmosphere, we conducted thermodynamic and computational fluid dynamics (CFD) analyses. Methanol was selected as the carbon source based on thermodynamic calculations, which revealed that at high temperatures, methanol forms CO and H2 as thermodynamically stable species instead of carbon (C), thereby preventing soot formation. Moreover, methanol undergoes catalytic cracking exclusively in the presence of catalysts, further preventing soot formation. This approach allows operation at high partial pressure, even above the upper explosive limit (UEL), effectively preventing combustion. A 600 mm cooling zone was incorporated into the reactor to lower the outlet gas temperature below methanol's auto-ignition point, mitigating combustion risks. CFD calculations were employed to determine the necessary cooling zone length. Additionally, we developed a predictive model using the XGBoost machine learning method to efficiently map the parameter space for CNT fiber spinning, achieving an accuracy of 95.24%. The resulting CNT fibers demonstrate high electrical conductivity (240 ± 24 S/cm) and a low ID/ IG ratio, indicating a high degree of crystallinity.
        4,600원
        6.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Considering the intrinsic activity of non-precious metal oxygen reduction reaction (ORR) catalysts is typically lower than that of precious metal catalysts, it is crucial to focus on the rational design of their micro-morphology and active site. This paper employed a simple molten salt-mediated template method to fabricate a Fe3C composite N-doped C catalyst with a layered porous framework ( Fe3C@NC). Tannic acid was utilized to form a strong coordination with iron to limit the grain size of Fe3C nanocrystals generated by high-temperature pyrolysis. Moreover, urea achieved nitrogen doping in tannic acidderived porous carbon, while the graphite phase nitrogen-doped carbon (g-C3N4) formed by its pyrolysis, together with the molten salt-mediated environment, jointly controlled the two-dimensional sheet-like structure of the material. The optimized Fe3C@ NC-800 demonstrated efficient ORR performance, with an ORR half-wave potential of 0.883 V. Its application as a cathode catalyst in a liquid zinc-air battery (ZABs) exhibits a maximum power density of 211.5 mW cm− 2, surpassing that of a Pt/C-based ZAB and indicating the potential practical utility of this material.
        4,200원
        7.
        2025.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigated the process of reclaiming Mo from calcined waste hydrotreating (CWHT) catalysts using tributyl phosphate (TBP) as an extractant with electron-withdrawing properties. Using inductively coupled plasma (ICP) technology, the optimal operating conditions for Mo recovery were determined based on the metal ion content in different processes. Considering the pH impact on metal species in solution, an acid leaching solution with 6 M sulfuric acid was employed. After 3 h of reaction, 94 wt% of the Mo was transferred from the WHT catalyst to the acid leaching solution. Adjusting the filtrate to a pH of 1.5 allowed the TBP to selectively extract over 98.8 wt% of Mo from the aqueous filter solution into the organic phase. MC-Cabe-Thiele theory predicts that a three-stage countercurrent extraction can reduce Mo to less than 0.2 wt%. Stripping moved approximately 98 wt% of the Mo from the organic to the inorganic phases. The recovered colorless organic tributyl phosphate can be used in the recycled extraction process.
        4,500원
        8.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 선교사들이 직면한 정서적·영적 도전과 탈진 문제를 해결하기 위해 렉시오 디비나(Lectio Divina)와 심리학적 도구를 융합 한 통합적 영성훈련 모델을 제안한다. 렉시오 디비나는 하나님의 임재 를 경험하며 관상 단계로 나아갈 수 있는 강력한 영성훈련 방법이다. 그러나 묵상과 기도 단계에서 떠오르는 부정적 감정과 왜곡된 신념은 영적 여정을 어렵게 만들기도 한다. 본 연구는 심리학적 접근을 영성훈 련의 마중물로 활용하여, 렉시오 디비나의 훈련 효과를 극대화할 방안 을 모색한다. 신경 논리 수준(Neurological Levels)은 환경, 행동, 능력, 신념과 가치, 정체성, 영성의 여섯 층위를 체계적으로 분석하여 개인의 문제를 탐구하고, 심상기법(Imagery Therapy)은 부정적 심상 을 치유적이고 긍정적인 심상으로 전환함으로써 정서적 안정과 영적 성숙을 도모한다. 렉시오 디비나와 심리학적 도구를 융합한 영성훈련 모델은 선교사들의 내적 치유를 돕고, 하나님의 은혜 안에서 지속 가능한 사역과 공동체적 사명을 감당할 수 있도록 지원할 뿐만 아니라, 앞으로도 심리학적 접근과 영성훈련이 융합된 다양한 선교사 멤버케어 프로그램 개발에 기여하는 토대가 되길 바란다.
        6,900원
        9.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Silicon carbide (β-SiC) was synthesized through an improved sol–gel method, then Ni/SiC catalysts were prepared using a hydrothermal method. The catalysts were characterized using TEM, H2- TPR, CO2- TPD and N2- TPD, etc. The results showed that the synthesized β-SiC had a large specific surface area, promoting the dispersion of Ni species and thus exposing more active sites. The interaction between Ni species and β-SiC contributed significantly to catalytic performance. Furthermore, the strong alkalinity of catalyst could adjust the bond energy of the active metal and N (M–N), which were conducive to desorption of the recombinant N2 from the metal surface, promoting to ammonia decomposition. Among the Ni/SiC catalysts, 30Ni/SiC-700 synthesized with the Ni loading of 30 wt% and calcination temperature of 700 °C, exhibited the optimal ammonia conversion rate of 93.4% at 600 °C under the space speed of 30,000 mL∙gcat −1∙h−1, and demonstrated a long-term stability, suggesting a very promising catalyst in ammonia decomposition.
        4,200원
        10.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The economical manufacturing of high-quality graphene has been a significant challenge in its large-scale application. Previously, we used molten Sn and Cu as the heat-transfer agent to produce multilayer graphene on the surface of gas bubbles in a bubble column. However, element Sn and Cu have poor catalytic activity toward methane pyrolysis. To further improve the yield of graphene, we have added active Ni into Sn to construct a Sn–Ni alloy in this work. The results show that Sn–Ni alloy is much more active for methane pyrolysis, and thus more graphene is obtained. However, the graphene product is more defective and thicker because of the faster growth rate. By using 300 ml molten Sn–Ni alloy (70 mm height) and 500 sccm source gas ( CH4:Ar = 1:9), this approach produces graphene with a rate of 0.61 g/hr and a conversion rate of methane to carbon of 37.9% at 1250 ℃ and ambient pressure. The resulting graphene has an average atom layer number of 22, a crumpled structure and good electrical conductivity.
        4,000원
        11.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the efficient method for DPF(Diesel Particulate Filter) regeneration of diesel engines is using post fuel injection, which is injected into the combustion chamber during the expansion stroke. This method generates a heat for DPF regeneration by oxidation of HC with Pt coated on DOC(Diesel Oxidation Catalyst). This study investigates heat generation of DOC using post fuel injection.
        3,000원
        16.
        2024.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Among the products of the electrocatalytic reduction of carbon dioxide (CO2RR), CO is currently the most valuable product for industrial applications. However, poor stability is a significant obstacle to CO2RR. Therefore, we synthesized a series of bimetallic organic framework materials containing different ratios of tungsten to copper using a hydrothermal method and used them as precursors. The precursors were then subjected to pyrolysis at 800 °C under argon gas, and the M-N bimetallic sites were formed after 2 h. Loose porous structures favorable for electrocatalytic reactions were finally obtained. The material could operate at lower reduction potentials than existing catalysts and obtained higher Faraday efficiencies than comparable catalysts. Of these, the current density of WCu-C/N (W:Cu = 3:1) could be stabilized at 7.9 mA ‧ cm-2 and the FE of CO reached 94 % at a hydrogen electrode potential of -0.6 V (V vs. RHE). The novel materials made with a two-step process helped to improve the stability and selectivity of the electrocatalytic reduction of CO2 to CO, which will help to promote the commercial application of this technology.
        4,500원
        17.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Municipal landfill leachate (MLL) contamination in surface water is a critical global issue due to the high concentration of toxic organics and recalcitrants. The biological treatment of MLL is ineffective due to an elevated concentration of ammoniacal nitrogen, which restricts the production of the recalcitrant degrading laccase enzyme. In this context, integrating an external laccase-anchored carbon catalyst (LACC) matrix system with the microbial system could be an efficient strategy to overcome the drawbacks of conventional biological MLL treatment technologies. In the present study, the LACC matrix was synthesized by utilizing nanoporous activated carbon (NAC) functionalized ethylene diamine (EDA) and glutaraldehyde (GA) (GA/EDA/NAC) matrix for the anchoring of laccase. The maximum anchoring capacity of laccase onto GA/EDA/ NAC was achieved to be 139.65 U/g GA/EDA/NAC at the optimized anchoring time, 60 min; pH, 5; temperature, 30 °C, and mass of GA/EDA/NAC, 300 mg and was confirmed by Fourier transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM), and X-ray Diffraction (XRD) analyses. Further, the mechanistic study revealed the involvement of covalent bonding in the anchoring of laccase onto the functionalized surface of the GA/EDA/NAC matrix. The adsorption isotherm and kinetics of laccase anchoring onto the GA/EDA/NAC matrix were performed to evaluate its field-level application. Subsequently, the sequential microbial system (I-stage bacterial treatment followed by II-stage fungal treatment) and III-stage LACC matrix system could effectively reduce the COD by 94.2% and phenol by 92.36%. Furthermore, the Gas Chromatography-Mass Spectrophotometry (GC–MS) and FT-IR analyses confirmed the effective degradation of organic compounds and recalcitrants by the integrated microbial and LACC matrix system. The study suggested that the application of the LACC matrix system has resulted in the complete treatment of real-time MLL by overcoming the negative interference of elevated ammoniacal nitrogen concentration. Thus, the integrated microbial and LACC matrix approach could be considered to effectively treat the MLL without any secondary pollution generation.
        5,200원
        18.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Exploring highly efficient, and low-cost oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts is extremely vital for the commercial application of advanced energy storage and conversion devices. Herein, a series of graphene-like C2N supported TMx@C2N, (TM = Fe, Co, Ni, and Cu, x = 1, 2) single- and dual-atom catalysts are designed. Their catalytic performance is systematically evaluated by means of spin-polarized density functional theory (DFT) computations coupled with hydrogen electrode model. Regulating metal atom and pairs can widely tune the catalytic performance. The most promising ORR/OER bifunctional activity can be realized on Cu2@ C2N with lowest overpotential of 0.46 and 0.38 V for ORR and OER, respectively. Ni2@ C2N and Ni@C2N can also exhibit good bifunctional activity through effectively balancing the adsorption strength of intermediates. The correlation of reaction overpotential with adsorption free energy is well established to track the activity and reveal the activity origin, indicating that catalytic activity is intrinsically governed by the adsorption strength of reaction intermediates. The key to achieve high catalytic activity is to effectively balance the adsorption of multiple reactive intermediates by means of the synergetic effect of suitably screened bimetal atoms. Our results also demonstrate that lattice strain can effectively regulate the adsorption free energies of reaction intermediates, regarding it as an efficient strategy to tune ORR/OER activity. This study could provide a significant guidance for the discovery and design of highly active noble-metal-free carbon-based ORR/OER catalysts.
        5,100원
        19.
        2024.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This review explores the potential of pillared bentonite materials as solid acid catalysts for synthesizing diethyl ether, a promising renewable energy source. Diethyl ether offers numerous environmental benefits over fossil fuels, such as lower emissions of nitrogen oxides (NOx) and carbon oxides (COx) gases and enhanced fuel properties, like high volatility and low flash point. Generally, the synthesis of diethyl ether employs homogeneous acid catalysts, which pose environmental impacts and operational challenges. This review discusses bentonite, a naturally occurring alumina silicate, as a heterogeneous acid catalyst due to its significant cation exchange capacity, porosity, and ability to undergo modifications such as pillarization. Pillarization involves intercalating polyhydroxy cations into the bentonite structure, enhancing surface area, acidity, and thermal stability. Despite the potential advantages, challenges remain in optimizing the yield and selectivity of diethyl ether production using pillared bentonite. The review highlights the need for further research using various metal oxides in the pillarization process to enhance surface properties and acidity characteristics, thereby improving the catalytic performance of bentonite for the synthesis of diethyl ether. This development could lead to more efficient, environmentally friendly synthesis processes, aligning with sustainable energy goals.
        4,300원
        20.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A series of ZIF-67-C-IL catalysts were prepared using ZIF-67 and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([ BMIM]NTf2) ionic liquid as precursors. The structure of the catalysts was characterized by XRD, TEM, SEM and XPS. The catalytic performance of the catalysts for the oxygen reduction reaction (ORR) was evaluated in a three-electrode system. The results confirmed that the high-temperature treatment of the precursors resulted in the formation of N, S codoped carbon-encapsulated Co9S8 nanoparticles. To create N, S co-doped carbon coated Co9S8 nanoparticle catalysts, ionic liquids are used as sulfur and nitrogen sources. The catalytic activity of ORR can be improved using N, S co-doped carbon to prevent the aggregation of Co9S8 nanoparticles. Graphitized and N, S co-doped carbon shells are optimal for achieving high activity stability. Optimal 600-ZIF-67-C(1:1.5)-30IL catalytic activity was observed for ORR. The half-wave potential of ORR was 0.88 V vs. RHE in 0.1 mol L− 1 KOH, with a limit current density of 4.70 mA cm− 2. Similar ORR electrocatalytic activity was observed between this catalyst and commercial Pt/C (20 wt%).
        4,000원
        1 2 3 4 5