http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
El-Deen, Ahmed G,El-Newehy, Mohamed,Kim, Cheol Sang,Barakat, Nasser AM Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1
<P>Nitrogen-doped graphene decorated by iron-nickel alloy is introduced as a promising electrode material for supercapacitors. Compared to pristine and Ni-decorated graphene, in acid media, the introduced electrode revealed excellent specific capacitance as the corresponding specific capacitance was multiplied around ten times with capacity retention maintained at 94.9% for 1,000 cycles. Briefly, iron acetate, nickel acetate, urea, and graphene oxide were ultrasonicated and subjected to MW heating and then sintered with melanin in Ar. The introduced N-doped FeNi@Gr exhibits remarkable electrochemical behavior with long-term stability.</P>
Mohamed Hassan El-Newehy,Salem Slayyem Al-Deyab,Rajkumar Nirmala,Ahmed Abdel-Megeed,Hak Yong Kim 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.2
Electrospun nylon-6/chitosan (nylon-6/Ch) nanofibers were prepared by nanospider technology. Quaternary ammonium salts as antibacterial agent were immobilized onto electrospun nylon-6/Ch nanofibers via surface modification by soaking the mat in aqueous solution of glycidyltrimethylammonium chloride (GTMAC) at room temperature overnight to give nylon-6/N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (nylon-6/HTCC). The morphological,structural and thermal properties of the nylon-6/ch nanofibers were studied by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). Biological screening has demonstrated the antibacterial activity of the electrospun nanofibers against Gram negative bacteria, Escherichia coli 35218, and Pseudomonas aeruginosa and Gram positive bacteria,Staphylococcus aureus 24213 among the tested microbes. Thus, the study ascertains the value of the use of electrospun nanofibers, which could be of considerable interest to the development of new antibacterial materials for biomedical applications.
Barakat, Nasser A M,El-Newehy, Mohamed,Al-Deyab, Salem S,Kim, Hak Yong Springer 2014 NANOSCALE RESEARCH LETTERS Vol.9 No.1
<P>In this study, Co/Cu-decorated carbon nanofibers are introduced as novel electrocatalyst for methanol oxidation. The introduced nanofibers have been prepared based on graphitization of poly(vinyl alcohol) which has high carbon content compared to many polymer precursors for carbon nanofiber synthesis. Typically, calcination in argon atmosphere of electrospun nanofibers composed of cobalt acetate tetrahydrate, copper acetate monohydrate, and poly(vinyl alcohol) leads to form carbon nanofibers decorated by CoCu nanoparticles. The graphitization of the poly(vinyl alcohol) has been enhanced due to presence of cobalt which acts as effective catalyst. The physicochemical characterization affirmed that the metallic nanoparticles are sheathed by thin crystalline graphite layer. Investigation of the electrocatalytic activity of the introduced nanofibers toward methanol oxidation indicates good performance, as the corresponding onset potential was small compared to many reported materials; 310 mV (vs. Ag/AgCl electrode) and a current density of 12 mA/cm<SUP>2</SUP> was obtained. Moreover, due to the graphite shield, good stability was observed. Overall, the introduced study opens new avenue for cheap and stable transition metals-based nanostructures as non-precious catalysts for fuel cell applications.</P>
Thamer, B.M.,El-Newehy, M.H.,Al-Deyab, S.S.,Abdelkareem, M.A.,Kim, H.Y.,Barakat, N.A.M. Elsevier 2015 Applied Catalysis A Vol.498 No.-
Among the nanosupports, carbon nanofibers distinctly enhance the performance of the functional electrocatalysts because the adsorption capacity and low resistance electron transfer due to the large axial ratio. Moreover, nitrogen doping shows positive influence toward electrooxidation ability. In this study, Co-incorporated and nitrogen-doped carbon nanofibers are introduced as effective non-precious electrocatalyst for methanol oxidation in the alkaline medium. The introduced NFs have been prepared using facile, simple, high yield, low cost, and effective technique; electrospinning. Typically, calcination of cobalt acetate/urea/poly(vinyl alcohol) electrospun mats at 850<SUP>o</SUP>C in argon atmosphere leads to produce the introduced nanofibers. The structure, composition and morphology were characterized by FT-IR, XRD, EDX, FE-SEM and TEM techniques. The electrocatalytic activity of the introduced nanofibers toward methanol oxidation was evaluated by cyclic voltammetry (CV). Study the influence of the nitrogen content could be investigated by adjusting the urea content in the original electrospun nanofiber mats. The results indicated that the activity of the catalyst increases with increasing urea content in the electrospun solution up to 4%. A maximum current density was 100.84mAcm<SUP>-2</SUP> for Co/N(4%)-CNFs that was higher than the undoped ones (63.56mAcm<SUP>-2</SUP>). Moreover, good chemical stability was observed due to covering the metals NPs by carbon shells. Overall, nitrogen doping enhances electrocatalytic activity of Co/CNFs toward methanol oxidation in alkaline media.
Yousef, A.,Brooks, R.M.,El-Halwany, M.M.,EL-Newehy, M.H.,Al-Deyab, S.S.,Barakat, N.A.M. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.1
Cu<SUP>0</SUP>/S-doped TiO<SUB>2</SUB> nanoparticles (NPs)-decorated carbon nanofibers (CNFs) were introduced as a novel photocatalyst for the hydrolysis of ammonia borane under visible light. Nanofibers were prepared by electrospinning of a solution composed of titanium isopropoxide, polyvinylpyrroliodine, copper acetate tetrahydrate, and ammonium sulfide. Calcination of the formed nanofiber mats in Ar at 800<SUP>o</SUP>C led to thermal decomposition of CuS to Cu<SUP>0</SUP> and S. Finally, the obtained nanofibers revealed a better photocatalytic activity over that of the other used photocatalysts. The hydrogen evolution was approximately 60mL, 35mL, and 20mL in 40min using nanocatalyst and TiO<SUB>2</SUB>-CNFs, and TiO<SUB>2</SUB> NFs, respectively. The good nanofibrous morphology and electron-transfer, and high surface area are the main features of the introduced nanofibers.
One-step synthesis of Co-TiC-carbon composite nanofibers at low temperature
Yousef, Ayman,Brooks, Robert.M.,Abutaleb, Ahmed,El-Newehy, Mohamed H.,Al-Deyab, Salem S.,Kim, Hak Yong Elsevier 2017 CERAMICS INTERNATIONAL Vol.43 No.7
<P><B>Abstract</B></P> <P>Cobalt-titanium carbide-carbon composite nanofibers (Co-TiC-CNFs [nanocomposite]) were prepared using one-step electrospinning of a sol-gel consisting of titanium(IV) isopropoxide, polyvinylpyrroliodine and cobalt acetate tetrahydrate. Dried electrospun nanofiber mats were sintered in an argon (Ar) atmosphere at 850°C, i.e. at a lower temperature compared to literature data. The synthesized nanocomposite showed good electrical conductivity and could be used in various applications. The TiC preparation method used in this study could open the way for synthesizing different nanocomposite based metal carbides.</P>
Yousef, Ayman,Barakat, Nasser A.M.,EL-Newehy, Mohamed H.,Ahmed, M.M.,Kim, Hak Yong Elsevier 2015 Colloids and surfaces. A, Physicochemical and engi Vol.470 No.-
<P><B>Abstract</B></P> <P>Cu(0) nanoparticles supported on TiO<SUB>2</SUB> nanofibers (Cu-decorated TiO<SUB>2</SUB> NFs) are introduced as an effective photocatalyst for hydrolytic dehydrogenation of ammonia borane (AB) under solar radiation. The introduced Cu-decorated TiO<SUB>2</SUB> NFs were prepared using electrospinning followed by hydrothermal treatment as a novel route for preparation of metal-decorated metal oxide nanofibers. Interestingly, the utilized physicochemical characterizations showed that the prepared nanocatalyst composed of core TiO<SUB>2</SUB> NFs decorated by Cu(0) NPs. A strong photocatalytic activity for catalytic hydrolysis of AB under solar radiation using the introduced nanocatalysts was observed. The results reveal that high rate of hydrogen release from ammonia borane (2.75 equivalent moles) as compared to undecorated TiO<SUB>2</SUB> NFs (1.6 equivalent moles) and pristine Cu NPs (1.2 equivalent moles). The obtained high hydrogen production, in case of the introduced Cu-decorated TiO<SUB>2</SUB> NFs, is attributed to the dual effect of counter parts. Furthermore, the introduced nanofibers could be utilized for three successive cycles with the same efficiency which reflects high stability. Moreover, the photocatalytic activity of the introduced NFs was further confirmed by photodegradation of methylene blue (MB) under solar radiation; complete removal was observed after 120min.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cu(0) nanoparticles covered surface of titanium dioxide nanofibers. </LI> <LI> High catalytic activity in hydrogen release from ammonia borane. </LI> <LI> Prepared photocatalyst can be reused with the same activity. </LI> </UL> </P>
Barakat, Nasser AM,Abdelkareem, Mohammad Ali,El-Newehy, Mohamed,Kim, Hak Yong Springer 2013 Nanoscale research letters Vol.8 No.1
<P>In this study, the influence of the morphology on the electrocatalytic activity of nickel oxide nanostructures toward methanol oxidation is investigated. Two nanostructures were utilized: nanoparticles and nanofibers. NiO nanofibers have been synthesized by using the electrospinning technique. Briefly, electrospun nanofiber mats composed of polyvinylpyrolidine and nickel acetate were calcined at 700°C for 1 h. Interestingly, compared to nanoparticles, the nanofibrous morphology strongly enhanced the electrocatalytic performance. The corresponding current densities for the NiO nanofibers and nanoparticles were 25 and 6 mA/cm<SUP>2</SUP>, respectively. Moreover, the optimum methanol concentration increased to 1 M in case of the nanofibrous morphology while it was 0.1 M for the NiO nanoparticles. Actually, the one-dimensional feature of the nanofibrous morphology facilitates electrons' motion which enhances the electrocatalytic activity. Overall, this study emphasizes the distinct positive impact of the nanofibrous morphology on the electrocatalytic activity which will open a new avenue for modification of the electrocatalysts.</P>
A Study on Electrospun Nylon-6/TiO2 Composite Nanofibers
R. Nirmala,Jeong Jin Won,김학용,R. Navamathavan,Yi Chuan,Mohamed El-Newehy,Salem S Al-Deyab 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10
We report on the preparation and the characterization of TiO2 nanoparticles incorporated with nylon-6 composite nanofibers by using electrospinning technique. Two different composite nanofiber mats with TiO2 nanoparticles sizes of 20 and 300 nm were prepared. The resultant nanofibers exhibited good incorporation of TiO2 nanoparticles. The doping of TiO2 nanoparticles into the nylon-6 nanofibers was confirmed by using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) spectroscopy. The measurement of the electrical conductivity of the TiO2 nanoparticles incorporated with nylon-6 nanofibers were carried out. Current-voltage (I–V) characteristics revealed that the current was enhanced for the sample with 300 nm TiO2 nanoparticles compared to that with 20-nm TiO2 nanoparticles.