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        검색결과 2

        1.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present work focused on the determination of texture, morphology, crystallinity, and gas adsorption characteristics of porous graphene prepared from rice husks ashes at different stabilization temperature. The stabilization temperature applied in this work is 100 °C, 200 °C, 300 °C, and 400 °C to convert rice husk into rice husk ashes (RHA). Chemical activation was adopted at temperature 800 °C using potassium hydroxide (KOH) as dehydrating agent at (1:5) impregnation ratio to convert RHA into rice husk ashes-derived graphene (GRHA). The resultant GRHA were characterized in terms of their morphological changes, SSA, crystallinity, and functional group with TEM, the BET method, Raman spectroscopy, and XRD analysis, respectively. Results from this study showed that the SSA of the GRHA at stabilization temperature 200 °C (1556.3 m2/g) is the highest compared to the other stabilization temperature. Raman spectroscopy analysis revealed that all GRHA samples possess D, G, and 2D bands, which confirm the successful synthesis of the rice husks into porous graphene-like materials, known as GRHA. Appearance of diffraction peak in XRD at 44.7° indicating the graphitic structure of all the GRHA samples. Meanwhile, the TEM images of GRHA200 exhibited wrinkled structures due to the intercalation of oxygen and a few layers of graphene flakes. These wrinkled structures and graphene layers are the other factors that lead to the highest SSA of GRHA200 compared to other prepared samples GRHA. Furthermore, the adsorption capacity of CH4 for GRHA200 is up to 43 cm3/g at 35 bar and ambient temperature, almost double the adsorption capacity performance of GRHA400 at the same operating pressure and temperature.
        4,000원
        2.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, composite PAN-based ACNFs embedded with MgO and MnO2 were prepared by the electrospinning method. The resultant pristine ACNFs, ACNF/MgO and ACNF/MnO2 were characterized in terms of their morphological changes, SSA, crystallinity and functional group with FESEM-EDX, the BET method, XRD and FTIR analysis, respectively. Results from this study showed that the SSA of the ACNF/MgO composite (1893 m2 g–1) is significantly higher than that of the pristine ACNFs and ACNF/MnO2 which is 478 and 430 m2 g–1, respectively. FTIR analysis showed peaks of 476 and 547 cm–1, indicating the presence of MgO and MnO2, respectively. The FESEM micrographs analysis showed a smooth but coarser structure in all the ACNFs. Meanwhile, the ACNF/MgO has the smallest fiber diameter (314.38±62.42 nm) compared to other ACNFs. The presence of MgO and MnO2 inside the ACNFs was also confirmed with EDX analysis as well as XRD. The adsorption capacities of each ACNF toward CH4 were tested with the volumetric adsorption method in which the ACNF/MgO exhibited the highest CH4 adsorption up to 2.39 mmol g–1. Meanwhile, all the ACNF samples followed the pseudo-second order kinetic model with a R2 up to 0.9996.
        4,000원