Journal articles: 'CNF catalyst'

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Liu, Sichen, Víctor Frutos, María Ariadna Álvarez-Montero, Luisa María Gómez-Sainero, Juan José Rodriguez, and Maria Martin-Martinez. "Influence of Surface Chemistry of Carbon Nanofibers on the Hydrodechlorination of Chloroform to Olefins." Catalysts 12, no. 10 (September 21, 2022): 1084. http://dx.doi.org/10.3390/catal12101084.

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Functionalized carbon nanofibers (CNF) are fascinating materials to be used as supports in Pd-based catalysts for the treatment of waste chloroform (TCM) to produce light olefins through the catalytic hydrodechlorination (HDC). The CNF were functionalized by HNO3, HCl, and urea. Compared to the Pd supported on un-treated CNF, all the catalysts using functionalized CNF as support showed lower turnover frequency values with higher stability, owing to their smaller Pd nanoparticles (NPs). These smaller Pd NPs are formed due to the stronger metal–support interactions promoted by the higher concentration of surface groups on the functionalized catalysts. Since the smaller Pd NPs could hinder the hydrogenation of olefins to paraffins, the selectivity to olefins increased on the functionalized catalysts. Moreover, the N-doped CNF was successfully formed on the catalyst functionalized by urea. Since the nitrogen functional groups (pyridinic N and pyrrolic N) could provide much stronger metal–support interactions compared to the oxygen functional groups on the other catalysts, the catalyst functionalized by urea showed the smallest Pd NPs among the four catalysts, leading to the highest selectivity to light olefins.

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Din, Israf Ud, Maizatul Shima Shaharun, Duvvuri Subbarao, and A. Naeem. "Synthesis, Characterization and Activity Pattern of Carbon Nanofibres Based Cu-ZrO₂ Catalyst in the Hydrogenation of Carbon Dioxide to Methanol." Advanced Materials Research 925 (April 2014): 349–53. http://dx.doi.org/10.4028/www.scientific.net/amr.925.349.

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Carbon nanofibers based Cu-ZrO2 catalysts (Cu-ZrO2/CNF) were synthesized by deposition precipitation method. Carbon nanofibers of herringbone type were used as a catalyst support. Before using as catalyst support, carbon nanofibers were oxidized to (CNF-O) with 10 % (v/v) nitric acid solution. A series of catalyst with various copper loadings of 10, 15 and 20 wt% were synthesized. X-ray diffraction (XRD) study revealed that degree of crystallization of catalyst increase with increasing the concentration of copper content in the catalyst. BET studies showed higher surface area for low loading of copper. Temperature-Programmed Reduction (TPR) analyses concluded good interaction of catalyst particles with higher loading of copper. The performance of Cu-ZrO2/CNF catalysts in hydrogenation of CO2 reaction was studied in slurry-typed reactor at 443 K, 30 bar and H2: CO2 ratio of 3:1. The highest yield of methanol was achieved using the 20 wt% copper loading.

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Hesterberg Butzlaff, Ashley, Sattar Alsaedi, Jacob Fields, David Cwiertny, and Syed Mubeen Jawahar Hussaini. "Implementing Catalysts into Electrospun Composite Carbon Nanofiber (CNF) Electrodes for Ammonia Production from Photoelectrocatalytic Nitrate Reduction." ECS Meeting Abstracts MA2022-01, no. 40 (July 7, 2022): 1805. http://dx.doi.org/10.1149/ma2022-01401805mtgabs.

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While novel carbon nanomaterials can serve as electrodes with exceptional electrical properties, carbon nanofibers (CNFs) merit further investigation for applications as electrodes in environmentally-relevant photoelectrocatalysis. Tunable, durable CNF structures can be easily synthesized as a convenient framework for catalyst implementation. Herein we investigate how catalysts can be integrated into carbon nanofiber mats to enhance the photoelectrocatalysis of nitrate reduction. As a frequent contaminant in agriculturally-intensive regions, the negative value of nitrate containing streams may be used to produce ammonia as a value-added product and to improve water quality in the resulting output stream. Catalysts were implemented using different methods (in situ sol gel, chemical reduction, electrochemical) on two different CNF composites (with and without titanium dioxide). We focus on copper as a catalyst due to its promising performance and economic advantage over traditional platinum group metals. After thorough characterization of the catalyst-CNF frameworks via XPS, XRD, Raman, the catalyst performance was measured by nitrate reduction product selectivity, catalyst lifetime, and Faradaic efficiency. The flexibility of CNF synthesis and catalyst implementation will provide photoelectrodes with properties desirable for the electrochemical reduction of nitrate in environmental conditions to generate valuable products. This work will help identify the types and properties of next-generation carbon composite electrode materials that are most promising for resource recovery and for improving photoelectrochemical catalytic cells purposed for drinking water treatment.

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Souza Macedo, Luana, Victor Teixeira da Silva, and Johannes Bitter. "Activated Carbon, Carbon Nanofibers and Carbon-Covered Alumina as Support for W2C in Stearic Acid Hydrodeoxygenation." ChemEngineering 3, no. 1 (March 5, 2019): 24. http://dx.doi.org/10.3390/chemengineering3010024.

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Carbon materials play a crucial role in sorbents and heterogeneous catalysis and are widely used as catalyst support for several reactions. This paper reports on an investigation of tungsten carbide (W2C) catalyst on three types of carbon support, namely activated carbon (AC), carbon nanofibers (CNF) and carbon-covered alumina (CCA). We evaluated their activity and selectivity in stearic acid hydrodeoxygenation at 350 °C and 30 bar H2. Although all three W2C catalysts displayed similar intrinsic catalytic activities, the support did influence product distribution. At low conversions (<5%), W2C/AC yielded the highest amount of oxygenates relative to W2C/CNF and W2C/CCA. This suggests that the conversion of oxygenates into hydrocarbons is more difficult over W2C/AC than over W2C/CNF and W2C/CCA, which we relate to the lower acidity and smaller pore size of W2C/AC. The support also had an influence on the C18-unsaturated/C18-saturated ratio. At conversions below 30%, W2C/CNF presented the highest C18-unsaturated/C18-saturated ratio in product distribution, which we attribute to the higher mesopore volume of CNF. However, at higher conversions (>50%), W2C/CCA presented the highest C18-unsaturated/C18-saturated ratio in product distribution, which appears to be linked to W2C/CCA having the highest ratio of acid/metallic sites.

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Parveen, Nazish, Thi Hiep Han, Sajid Ali Ansari, and Moonyong Lee. "Sustainable Bio-Energy Production in Microbial Fuel Cell Using MnO2 Nanoparticle-Decorated Hollow Carbon Nanofibers as Active Cathode Materials." Journal of Nanoelectronics and Optoelectronics 16, no. 2 (February 1, 2021): 127–35. http://dx.doi.org/10.1166/jno.2021.2926.

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The widespread use of renewable energy remains a challenging and complex multidisciplinary problem. Developing alternatives using new technology such as nanotechnology is necessary to increase renewable energy’s scalability. Microbial fuel cells (MFCs) combined with nanotechnology can improve bioelectricity generation during wastewater treatment. In this study, hollow carbon nanofibers (H-CNF) were decorated with manganese oxide (MnO2) via a simple chemical reduction method. MnO2-decorated H-CNF prepared with varying concentrations of manganese precursor (MnO2@H-CNF) were characterized via different spectroscopic and microscopic techniques. The cathode catalyst performance of the MnO2@H-CNF was investigated in an //-type constructed MFC system using Shewanella Oneidensis MR1. The MnO2@H-CNF-1 in the assembled MFC displayed excellent power density of 25.7 mW/m2, which is higher than pure H-CNF (8.66 mW/m2), carbon cloth (5.10 mW/m2), and MnO2@H-CNF-3 (16 mW/m2). The maximum power generated in the MFC coupled with MnO2@H-CNF as a cathode catalyst may have been due to the synergistic effect of the MnO2@H-CNF, which increased the electric conductivity and catalytic activity in the MFC’s cathode chamber. These results demonstrate that the developed MnO2@H-CNF cathode catalyst could improve the MFC’s performance and reduce the operational costs of practical applications.

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Alcázar, Hermann E., Emilio Chire, María M. Vargas, Bryan L. Villagarcía, John Neira, Andre Contin, and Leopoldo O. Alcázar. "Production and characterization of carbon nanotubes by methane decomposition over Ni–Fe/Al₂O₃ catalyst and its application as nanofillers in polypropylene matrix." Materials Research Express 8, no. 11 (November 1, 2021): 115001. http://dx.doi.org/10.1088/2053-1591/ac327b.

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Abstract This paper studies the influence of metal precursors in the CVD´s catalyst synthesis of carbon nanotubes (CNTs) used as fillers in a polypropylene (PP) matrix (∼0.3 wt%). Two catalytic schemes, Fe/Al2O3 (50:50) and Ni–Fe/Al2O3 (40:10:50), were prepared to determine the influence of the reduction temperature over the characteristics and mechanical properties of CNT as PP fillers. The conversion temperature was varied to see the dependance of the CNT structure to this variable (700 °C–750 °C–800 °C). CNTs products were characterized by SEM and Raman spectroscopy. The SEM micrographs showed a sharper fiber type CNTs for the bimetallic catalyst and the Raman confirmed that better crystallites are obtain over the Fe catalyst. The Fe–PP composite presented enhanced mechanical properties when compare with Fe–Ni–PP, with tensile strength, hardness, and impact properties are higher in 16%, 9%, and 9% respectively. Other carbonaceous materials, as CNF, with less crystallinity presented poorer mechanical properties. Finally, can be stated that for the use of CNF as fillers in PP composites a Fe/Al2O3 catalyst, and a reaction temperature 700 °C–750 °C will produce a CNF with 60 nm mean diameter, is better than the use of Fe-Ni based catalysts.

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Luo, Mingsheng, Shuo Li, Zuoxing Di, He Li, Qinglong Liu, Baozhong Lü, Aimei Wang, Buchang Shi, and Iltaf Khan. "Fischer–Tropsch Synthesis: Study of Different Carbon Materials as Cobalt Catalyst Support." Reactions 2, no. 1 (March 10, 2021): 43–61. http://dx.doi.org/10.3390/reactions2010005.

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In this work, cobalt Fischer–Tropsch synthesis (FTS) catalyst supported on various carbon materials, i.e., carbon nanotube (CNT), activated carbon (AC), graphene oxide (GO), reduced graphene oxide (rGO), and carbon nanofiber (CNF), were prepared via impregnation method. Based on TGA, nitrogen physisorption, XRD, Raman spectroscopy, H2-TPR, NH3-TPD, ICP, SEM, and TEM characterization, it is confirmed that Co3O4 particles are dispersed uniformly on the supports of carbon nanotube, activated carbon and carbon nanofiber. Furthermore, the FT catalyst performance for as-prepared catalysts was evaluated in a fixed-bed reactor under the condition of H2:CO = 2:1, 5 SL·h−1·g−1, 2.5 MPa, and 210 °C. Interestingly, the defined three types of carbon materials exhibit superior performance and dispersion compared with graphene oxide and reduced graphene oxide. The thermal stability and pore structure of the five carbon materials vary markedly, and H2-TPR result shows that the metal–support interaction is in the order of Co/GO > Co/CNT > Co/AC > Co/CNF > Co/rGO. In brief, the carbon nanofiber-supported cobalt catalyst showed the best dispersion, the highest CO conversion, and the lowest gas product but the highest heavy hydrocarbons (C5+) selectivity, which can be attributed to the intrinsic property of CNF material that can affect the catalytic performance in a complicated way. This work will open up a new gateway for cobalt support catalysts on various carbon-based materials for Fischer–Tropsch Synthesis.

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Ozerova, Anna M., Arina R. Potylitsyna, Yury I. Bauman, Elena S. Tayban, Inna L. Lipatnikova, Anna V. Nartova, Aleksey A. Vedyagin, Ilya V. Mishakov, Yury V. Shubin, and Olga V. Netskina. "Synthesis of Chlorine- and Nitrogen-Containing Carbon Nanofibers for Water Purification from Chloroaromatic Compounds." Materials 15, no. 23 (November 25, 2022): 8414. http://dx.doi.org/10.3390/ma15238414.

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Chlorine- and nitrogen-containing carbon nanofibers (CNFs) were obtained by combined catalytic pyrolysis of trichloroethylene (C2HCl3) and acetonitrile (CH3CN). Their efficiency in the adsorption of 1,2-dichlorobenzene (1,2-DCB) from water has been studied. The synthesis of CNFs was carried out over self-dispersing nickel catalyst at 600 °C. The produced CNFs possess a well-defined segmented structure, high specific surface area (~300 m2/g) and high porosity (0.5–0.7 cm3/g). The addition of CH3CN into the reaction mixture allows the introduction of nitrogen into the CNF structure and increases the volume of mesopores. As a result, the capacity of CNF towards adsorption of 1,2-DCB from its aqueous solution increased from 0.41 to 0.57 cm3/g. Regardless of the presence of N, the CNF samples exhibited a degree of 1,2-DCB adsorption from water–organic emulsion exceeding 90%. The adsorption process was shown to be well described by the Dubinin–Astakhov equation. The regeneration of the used CNF adsorbent through liquid-phase hydrodechlorination was also investigated. For this purpose, Pd nanoparticles (1.5 wt%) were deposited on the CNF surface to form the adsorbent with catalytic function. The presence of palladium was found to have a slight effect on the adsorption capacity of CNF. Further regeneration of the adsorbent-catalyst via hydrodechlorination of adsorbed 1,2-DCB was completed within 1 h with 100% conversion. The repeated use of regenerated adsorbent-catalysts for purification of solutions after the first cycle of adsorption ensures almost complete removal of 1,2-DCB.

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Ud Din, Israf, Maizatul S. Shaharun, Duvvuri Subbarao, and A. Naeem. "Homogeneous Deposition Precipitation Method for Synthesis of Carbon Nanofibre Based Cu-ZrO₂ Catalyst for Hydrogenation of CO₂ to Methanol." Applied Mechanics and Materials 446-447 (November 2013): 83–87. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.83.

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Deposition precipitation method was employed to synthesize carbon nanofiber based Cu-ZrO2catalyst (Cu-ZrO2/CNF). Carbon nanofibre of herringbone type was used as a catalyst support. Prior deposition of catalyst particles, carbon nanofibre was oxidized to (CNF-O) with nitric acid solution. Catalyst was characterized by X-ray diffraction (XRD), Fourier Transmission Infrared (FTIR), Transmission Electron Microscopy (TEM) and Temperature-Programmed Reduction (TPR). Highly loaded, well-dispersed and thermally stable catalyst particles with average size of 4 nm were obtained by deposition precipitation method. Reaction studies confirmed the activity of the catalyst towards methanol formation.

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Woo, Seongwon, Jooyoung Lee, Dong Sub Lee, Jung Kyu Kim, and Byungkwon Lim. "Electrospun Carbon Nanofibers with Embedded Co-Ceria Nanoparticles for Efficient Hydrogen Evolution and Overall Water Splitting." Materials 13, no. 4 (February 13, 2020): 856. http://dx.doi.org/10.3390/ma13040856.

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In this study, simple electrospinning combined with pyrolysis were used to fabricate transition-metal-based-nanoparticle-incorporated carbon nanofiber (CNF) electrocatalysts for a high-efficiency hydrogen evolution reaction (HER) and overall water splitting. Co-CeO2 nanoparticle-incorporated carbon nanofibers (Co-CeO2@CNF) exhibit an outstanding electrocatalytic HER performance with an overpotential and Tafel slope of 92 mV and 54 mV/dec, respectively. For the counterpart, electrolysis, we incorporate the widely used Ni2Fe catalyst with a high oxygen evolution reaction (OER) activity into the carbon nanofiber (Ni2Fe@CNF). To evaluate their electrochemical properties for the overall water splitting, Co-CeO2@CNF and Ni2Fe@CNF were used as the HER and OER electrocatalysts in an alkaline electrolyzer. With the paired Co-CeO2@CNF and Ni2Fe@CNF electrodes, an overall water splitting current density of 10 mA/cm2 was achieved by applying 1.587 V across the electrodes with a remarkably lower overpotential of 257 mV compared to that of an electrolyzer comprised of Pt/C and IrO2 electrodes (400 mV). Owing to the conformal incorporation of nanoparticles into the CNF, the electrocatalysts exhibit significant long-term durability over 70 h of overall water splitting. This study provides rational designs of catalysts with high electrochemical catalytic activity and durability to achieve overall water splitting.

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A. Karim, Nabila, Norilhamiah Yahya, Muhammad Syafiq, and Siti Kartom Kamarudin. "Electrochemical Reaction and Dissociation of Glycerol on PdAu Surface Catalyst." Sains Malaysiana 49, no. 12 (December 31, 2020): 3091–100. http://dx.doi.org/10.17576/jsm-2020-4912-21.

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Direct Glycerol Fuel Cell is one of the alternative energy that can produce electricity without burning. The production of electricity without combustion can reduce the use of fossil fuel as well as reduce environmental pollution. A new catalyst of PdAu has been synthesized in this study to increase the activity of the glycerol oxidation reaction. Morphologies analysis was performed on CNF-supported synthesized PdAu. FESEM and TEM image show the PdAu supported on the CNF surface. Both PdAu and CNF has a diameter size of 4-6 nm and 80-130 nm, respectively. In CV analysis, PdAu/CNF has produced an oxidation peak and current density at -0.9 V vs. SCE and 70 mA/cm2, respectively. Each mechanism of glycerol dissociation step during glycerol oxidation, different atomic active sites are required in PdAu. For example, for glycerol adsorption, Au atom as an active site while for *C3H7O3 requires Pd atom and Au atom as the active site. The Au catalyst model shows better adsorption as Au/CNF has a slightly more negative oxidation peak than PdAu. Nevertheless, the Au catalyst showed less durability compared to PdAu.

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Li, Meifeng, Wan Wang, Na Li, and Chungen Zhou. "Impaction of precursor gas-induced catalyst change on morphology, growth kinetics and field emission property of carbon nanofibers." RSC Advances 6, no. 50 (2016): 44224–31. http://dx.doi.org/10.1039/c6ra05185e.

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Three types of carbon nanofiber (CNF): filamentous CNF, chain-like CNF and thick CNF were successfully synthesized from three hydrocarbon precursor gases of ethylene (C₂H₄), n-hexane (n-C₆H₁₄) and n-dodecane (n-C₁₂H₂₆) on iron catalyst at 1073 K.

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van Thien Duc, Nguyen, Suriati Sufian, Nurlidia Mansor, and Noorhana Yahya. "Effect of Modification Techniques on Surface of Carbon Nanofiber as Catalyst Support." Applied Mechanics and Materials 625 (September 2014): 345–48. http://dx.doi.org/10.4028/www.scientific.net/amm.625.345.

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The intrinsic surface of carbon nanofiber (CNF) is important for supported catalyst preparation. The surface changes due to various techniques applied such as N2thermal and HNO3oxidation methods. The combination of different analyses is to observe the internal structure through Raman spectroscope, textural properties via N2physisorption and morphology of CNF using transmission electron microscope or through quantification of oxygen containing groups by acid base titration. As results, an extension of residence time increases the amount of amorphous and damages the structure of mesoporous CNF texture unexpectedly. The change from hydrophobic to hydrophilic surface of CNF is due to the growing number of oxygen. The surface area of CNF by HNO3treatment method produces 115.14m2/g which is higher than that of using thermal method.

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Gebremariam, Tesfaye Tadesse, Fuyi Chen, Yachao Jin, Qiao Wang, Jiali Wang, and Junpeng Wang. "Bimetallic NiCo/CNF encapsulated in a N-doped carbon shell as an electrocatalyst for Zn–air batteries and water splitting." Catalysis Science & Technology 9, no. 10 (2019): 2532–42. http://dx.doi.org/10.1039/c9cy00266a.

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El-Newehy, Mohamed H., Hany El-Hamshary, and Waheed M. Salem. "Solution Blowing Spinning Technology towards Green Development of Urea Sensor Nanofibers Immobilized with Hydrazone Probe." Polymers 13, no. 4 (February 11, 2021): 531. http://dx.doi.org/10.3390/polym13040531.

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Cellulose has been one of the most widespread materials due to its renewability, excellent mechanical properties, biodegradability, high absorption ability, biocompatibility and cheapness. Novel, simple and green colorimetric fibrous film sensor was developed by immobilization of urease enzyme (U) and tricyanofuran hydrazone (TCFH) molecular probe onto cellulose nanofibers (CNF). Cellulose acetate nanofibers (CANF) were firstly prepared from cellulose acetate using the simple, green and low cost solution blowing spinning technology. The produced CANF was exposed to deacetylation to introduce CNF, which was then treated with a mixture of TCFH and urease enzyme to introduce CNF-TCFH-U nanofibrous biosensor. CNF were reinforced with tricyanofuran hyrazone molecular probe and urease enzyme was encapsulated into calcium alginate biopolymer to establish a biocomposite film. This CNF-TCFH-U naked-eye sensor can be applied as a disposable urea detector. CNF demonstrated a large surface area and was utilized as a carrier for TCFH, which is the spectroscopic probe and urease is a catalyst. The biochromic CNF-TCFH-U nanofibrous biosensor responds to an aqueous medium of urea via a visible color signal changing from off-white to dark pink. The morphology of the generated CNF and CNF-TCFH-U nanofibrous films were characterized by different analytical tools, including energy-dispersive X-ray patterns (EDX), polarizing optical microscope (POM), Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). SEM images of CNF-TCFH-U nanofibers demonstrated diameters between 800 nm and 2.5 μm forming a nonwoven fabric with a homogeneous distribution of TCFH/urease-containing calcium alginate nanoparticles on the surface of CNF. The morphology of the cross-linked calcium alginate nanoparticles was also explored using transmission electron microscopy (TEM) to indicate an average diameter of 56–66 nm. The photophysical performance of the prepared CNF-TCFH-U was also studied by CIE Lab coloration parameters. The nanofibrous film biosensor displayed a relatively rapid response time (5–10 min) and a limit of detection as low as 200 ppm and as high as 1400 ppm. Tricyanofuran hydrazone is a pH-responsive disperse dye comprising a hydrazone detection group. Determination of urea occurs through a proton transfer from the hydrazone group to the generated ammonia from the reaction of urea with urease.

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Song, Rui, Xueqin Zhang, Huihui Wang, and Chuanfu Liu. "Polyoxometalate/Cellulose Nanofibrils Aerogels for Highly Efficient Oxidative Desulfurization." Molecules 27, no. 9 (April 27, 2022): 2782. http://dx.doi.org/10.3390/molecules27092782.

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Polyoxometalate (POM) presents great potential in oxidative desulfurization (ODS) reaction. However, the high dissolubility of POM in common solvents makes it difficult to recycle. Besides, the small specific surface area of POM also limits the interaction between them and the substrate. Depositing polyoxometalates onto three-dimensional (3D) network structured materials could largely expand the application of POM. Here, the surfaces of cellulose nanofibrils (CNFs) were modified with very few (3-Aminopropyl) trimethoxysilane (APTS) to endow positive charges on the surfaces of CNFs, and then phosphotungstic acid (PTA) was loaded to obtain the aerogel A-CNF/PTA as the ODS catalyst. FT-IR indicated the successful deposition of PTA onto aminosilane modified CNF surfaces. UV-VIS further suggested the stability of PTA in the aerogels. BET and SEM results suggested the increased specific surface area and the relatively uniform 3D network structure of the prepared aerogels. TGA analysis indicated that the thermal stability of the aerogel A-CNF/PTA50% was a little higher than that of the pure CNF aerogel. Most importantly, the aerogel A-CNF/PTA50% showed good catalytic performance for ODS. Catalysis results showed that the substrate conversion rate of the aerogel A-CNF/PTA50% reached 100% within 120 min at room temperature. Even after five cycles, the substrate conversion rate of the aerogel A-CNF/PTA50% still reached 91.2% during the dynamic catalytic process. This work provides a scalable and facile way to stably deposit POM onto 3D structured materials.

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Thakur, Digvijay B., R. M. Tiggelaar, K. Seshan, J. G. E. Gardeniers, and L. Lefferts. "Synthesis of Carbon Nanofibers as Support Layer for Metal Catalyst in a Microreactor for Three-Phase Reactions." Advances in Science and Technology 54 (September 2008): 231–36. http://dx.doi.org/10.4028/www.scientific.net/ast.54.231.

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Carbon Nanofibers (CNF) layers were synthesized nickel-based thin-films on flat fused silica substrates. CNF synthesis was performed via thermal catalytic chemical vapor deposition of ethylene using nickel as metal catalyst. Different underlayer metal thin films, viz. titanium, tantalum and titanium-tungsten were tested in order to obtain stable and well-attached CNF films on fused silica substrates. It is found in case of titanium CNFs are formed on the nickel, but due to severe Ni/Ti inderdiffusion the titanium film looses its adhesive function, as a consequence of which the formed CNF film detaches from the substrate. The use of tantalum or titanium-tungsten as adhesion layer resulted in stable and well-adhered CNF films on fused silica substrates, of which the morphology can be controlled by the growth time.

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Sri Aprilia, N. A., Aulia Chintia Ambarita, Karmila Karmila, M. Adam Armando, and Faisal Yusupi Guswara. "Isolation and Characterization of Cellulose Nanofiber (CNF) from Sugarcane Bagasse by Acid Hydrolysis with Addition of Ferric Chloride Catalyst (FeCl3 )." Oriental Journal of Physical Sciences 2, no. 2 (December 25, 2017): 103–8. http://dx.doi.org/10.13005/ojps02.02.09.

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Sugarcane bagass was used as effect of hydrolysis time for isolation of cellulose nanofiber (CNF) was done. The other components such as lignin and hemicellulose were removed from the biomass by adding NaOH and NaOCl and continue to synthesist of CNF has done using formic acid hydrolysis wiht addition of ferric chloride catalyst. FTIR analysis showed that were no significant variations in peak positions, This result did not affect the chemical compounds of CNF. XRD analysis showed increase the hydrolisis time also increase the crystallinity percentage and crystalline size. Increasing hydrolysis time would decreased the percentage yield of CNF.

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Zheng, Jun Sheng, Xin Sheng Zhang, Sun Wen, Ping Li, Chun An Ma, and Wei Kang Yuan. "A Novel Non-Metal Oxygen Reduction Electrocatalyst Based on Platelet Carbon Nanofiber." Advanced Materials Research 132 (August 2010): 264–70. http://dx.doi.org/10.4028/www.scientific.net/amr.132.264.

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A novel non-metal electrocatalyst based on platelet carbon nanofiber (p-CNF) is prepared, and a palladium electrocatalyst supported on activated carbon (AC) is also synthesized. The physico-chemistry properties of the p-CNF and palladium catalyst on AC (Pd/AC) are investigated by high resolution transmission electron microscopy, N2 physisorption and Raman spectra analysis. From cyclic voltammetric studies, it is found that p-CNF is more active than Pd/AC in acidic media. The p-CNF shows a more positive oxygen reduction reaction (ORR) onset reduction potential and a higher oxygen reduction current density than Pd/AC. Moreover, the ORR is controlled by a surface reaction process when Pd/AC is used, while it becomes diffusion controlled when p-CNF is used.

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Ponomarev, Igor I., Kirill M. Skupov, Olga M. Zhigalina, Dmitry N. Khmelenin, Ivan I. Ponomarev, Elizaveta S. Vtyurina, Evgeny N. Cherkovskiy, Victoria G. Basu, and Alexander D. Modestov. "Deposition of Pt Nanoparticles by Ascorbic Acid on Composite Electrospun Polyacrylonitrile-Based Carbon Nanofiber for HT-PEM Fuel Cell Cathodes." Catalysts 12, no. 8 (August 13, 2022): 891. http://dx.doi.org/10.3390/catal12080891.

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The efficient use of renewable energy sources requires development of new electrocatalytic materials for electrochemical energy storage systems, particularly fuel cells. To increase durability of high temperature polymer electrolyte fuel cell (HT-PEMFC), Pt/carbon black based catalysts should be replaced by more durable ones, for example Pt/carbon nanofibers (CNF). Here, we report for the first time the quantitative ascorbic acid assisted deposition of Pt onto electrospun polyacrylonitrile-based CNF composite materials. The effect of their subsequent post-treatment at various temperatures (250 and 500 °C) and media (vacuum or argon-hydrogen mixture) on the Pt/C catalyst morphology is investigated. All obtained samples are thoroughly studied by high resolution electron microscopy, and Pt electrochemically active specific surface area was evaluated by cyclic voltammetry.

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Melati, Asih. "Aplikasi Carbon Nano Fiber Terintegrasi dengan Karbon Aktif Serabut Kelapa untuk Pengolahan Limbah Laundry." Panangkaran: Jurnal Penelitian Agama dan Masyarakat 1, no. 2 (December 22, 2017): 277. http://dx.doi.org/10.14421/panangkaran.2017.0102-05.

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The study effect of temperature on the morphology of carbon nanotube (CNF) based coconut husk has been done. CNF is one of the nanotechnology products that can be applied to reduce the concentration of the especially Pb, Cd, Ni. Thepurpose of this study are temperature effect on CNF and determine the potential uses treatment of CNF in the laundry waste. The Growth of CNF used the chemical vapor deposition (CVD) method with a temperature variation of 6000 C,7000 C, and 8000 C. CNF synthesis involves reacting activated carbon from coconut shell, ferrocene (Fe(C5H5)2) as a catalyst, benzene as the carbon source,and argon gas flowed. The Purification of CNF using nitric acid (HNO3) 65%. The result of Energy Dispersive Spestroscopy (EDS) characterization indicate that increasing temperatures indicate increasing carbon content. CNF as adsorbent deposited on the laundry waste. The water quality test of the laundry waste showed that the adsorption of CNF likely reduce Pb level at 67,4% at a temperature of 6000C and DO concentration increases. CNF T has no effect on the amount of PH and Cd, while BOD and COD consentration increases.

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Lafia-Araga, Ruth Anayimi, Ronald Sabo, Omid Nabinejad, Laurent Matuana, and Nicole Stark. "Influence of Lactic Acid Surface Modification of Cellulose Nanofibrils on the Properties of Cellulose Nanofibril Films and Cellulose Nanofibril–Poly(lactic acid) Composites." Biomolecules 11, no. 9 (September 11, 2021): 1346. http://dx.doi.org/10.3390/biom11091346.

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In this study, cellulose nanofibrils (CNFs) were modified by catalyzed lactic acid esterification in an aqueous medium with SnCl2 as a catalyst. Films were made from unmodified and lactic acid-modified CNF without a polymer matrix to evaluate the effectiveness of the modification. Ungrafted and lactic acid-grafted CNF was also compounded with poly(lactic acid) (PLA) to produce composites. Mechanical, water absorption, and barrier properties were evaluated for ungrafted CNF, lactic acid-grafted CNF films, and PLA/CNF composites to ascertain the effect of lactic acid modification on the properties of the films and nanocomposites. FTIR spectra of the modified CNF revealed the presence of carbonyl peaks at 1720 cm−1, suggesting that the esterification reaction was successful. Modification of CNF with LA improved the tensile modulus of the produced films but the tensile strength and elongation decreased. Additionally, films made from modified CNF had lower water absorption, as well as water vapor and oxygen permeability, relative to their counterparts with unmodified CNFs. The mechanical properties of PLA/CNF composites made from lactic acid-grafted CNFs did not significantly change with respect to the ungrafted CNF. However, the addition of lactic acid-grafted CNF to PLA improved the water vapor permeability relative to composites containing ungrafted CNF. Therefore, the esterification of CNFs in an aqueous medium may provide an environmentally benign way of modifying the surface chemistry of CNFs to improve the barrier properties of CNF films and PLA/CNF composites.

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Potylitsyna, Arina R., Yuliya V. Rudneva, Yury I. Bauman, Pavel E. Plyusnin, Vladimir O. Stoyanovskii, Evgeny Y. Gerasimov, Aleksey A. Vedyagin, Yury V. Shubin, and Ilya V. Mishakov. "Efficient Production of Segmented Carbon Nanofibers via Catalytic Decomposition of Trichloroethylene over Ni-W Catalyst." Materials 16, no. 2 (January 15, 2023): 845. http://dx.doi.org/10.3390/ma16020845.

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The catalytic utilization of chlorine-organic wastes remains of extreme importance from an ecological point of view. Depending on the molecular structure of the chlorine-substituted hydrocarbon (presence of unsaturated bonds, intermolecular chlorine-to-hydrogen ratio), the features of its catalytic decomposition can be significantly different. Often, 1,2-dichloroethane is used as a model substrate. In the present work, the catalytic decomposition of trichloroethylene (C2HCl3) over microdispersed 100Ni and 96Ni-4W with the formation of carbon nanofibers (CNF) was studied. Catalysts were obtained by a co-precipitation of complex salts followed by reductive thermolysis. The disintegration of the initial bulk alloy driven by its interaction with the reaction mixture C2HCl3/H2/Ar entails the formation of submicron active particles. It has been established that the optimal activity of the pristine Ni catalyst and the 96Ni-4W alloy is provided in temperature ranges of 500–650 °C and 475–725 °C, respectively. The maximum yield of CNF for 2 h of reaction was 63 g/gcat for 100Ni and 112 g/gcat for 96Ni-4W catalyst. Longevity tests showed that nickel undergoes fast deactivation (after 3 h), whereas the 96Ni-4W catalyst remains active for 7 h of interaction. The effects of the catalyst’s composition and the reaction temperature upon the structural and morphological characteristics of synthesized carbon nanofibers were investigated by X-ray diffraction analysis, Raman spectroscopy, and electron microscopies. The initial stages of the carbon erosion process were precisely examined by transmission electron microscopy coupled with elemental mapping. The segmented structure of CNF was found to be prevailing in a range of 500–650 °C. The textural parameters of carbon product (SBET and Vpore) were shown to reach maximum values (374 m2/g and 0.71 cm3/g, respectively) at the reaction temperature of 550 °C.

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Huang, Bo-Wen, Xiao-Zhen Liao, Hong Wang, Chao-Nan Wang, Yu-Shi He, and Zi-Feng Ma. "Nanofibrous MnNi/CNF Composite Catalyst for Rechargeable Li/O2Cell." Journal of The Electrochemical Society 160, no. 8 (2013): A1112—A1117. http://dx.doi.org/10.1149/2.049308jes.

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25

Afonnikova, Sofya D., Anton A. Popov, Yury I. Bauman, Pavel E. Plyusnin, Ilya V. Mishakov, Mikhail V. Trenikhin Trenikhin, Yury V. Shubin, Aleksey A. Vedyagin, and Sergey V. Korenev. "Porous Co-Pt Nanoalloys for Production of Carbon Nanofibers and Composites." Materials 15, no. 21 (October 24, 2022): 7456. http://dx.doi.org/10.3390/ma15217456.

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The controllable synthesis of carbon nanofibers (CNF) and composites based on CNF (Metals/CNF) is of particular interest. In the present work, the samples of CNF were produced via ethylene decomposition over Co-Pt (0–100 at.% Pt) microdispersed alloys prepared by a reductive thermolysis of multicomponent precursors. XRD analysis showed that the crystal structure of alloys in the composition range of 5–35 at.% Pt corresponds to a fcc lattice based on cobalt (Fm-3m), while the CoPt (50 at.% Pt) and CoPt3 (75 at.% Pt) samples are intermetallics with the structure P4/mmm and Pm-3m, respectively. The microstructure of the alloys is represented by agglomerates of polycrystalline particles (50–150 nm) interconnected by the filaments. The impact of Pt content in the Co1-xPtx samples on their activity in CNF production was revealed. The interaction of alloys with ethylene is accompanied by the generation of active particles on which the growth of nanofibers occurs. Plane Co showed low productivity (~5.5 g/gcat), while Pt itself exhibited no activity at all. The addition of 15–25 at.% Pt to cobalt catalyst leads to an increase in activity by 3–5 times. The maximum yield of CNF reached 40 g/gcat for Co0.75Pt0.25 sample. The local composition of the active alloyed particles and the structural features of CNF were explored.

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Tarasov, Boris P., Artem A. Arbuzov, Alexei A. Volodin, Sergey A. Mozhzhukhin, and Mikhail V. Klyuev. "NICKEL-GRAPHENE CATALYST FOR MAGNESIUM HYDROGENATION AND FOR CARBON NANOSTRUCTURES SYNTHESIS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 8 (August 29, 2017): 43. http://dx.doi.org/10.6060/tcct.2017608.5645.

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The results of obtaining graphene-like nanomaterials (GLM) by reduction of graphite oxide, preparation of nickel-graphene catalysts and formation of carbon-graphene and magnesium-graphene composites are presented. The optimal preparation conditions and the functional characteristics of the obtained materials are determined. The method described in this work makes possible to obtain nickel-graphene composites (Ni/GLM) containing 5–25 wt.% of Ni nanoparticles of size 2–5 nm. Such composites are effective catalysts for the hydrogenation of magnesium. They were used to create hydrogen storage materials on magnesium base with a reversible capacity more 6.5 wt.% of hydrogen. The addition of Ni/GLM promotes an increase in the rate of Mg hydrogenation due to the high catalytic activity of nanoscale Ni in the dissociation of H2 molecules, and the coating of the fine particles of MgH2 with the GLM retains the submicron size of the Mg particles formed during dehydrogenation and ensures high thermal conductivity of the Mg/MgH2 + Ni/GLM composites. It was determined that in MgH2 + Ni/GLM composites, along with the stable α-phase of MgH2, a metastable γ-phase of MgH2 contains, which leads to a decrease in the dehydrogenation temperature by ~ 50 °C. Using Ni/GLM catalysts, carbon nanotubes (CNT) and nanofibers (CNF) on the surface of graphene-like structures were synthesized. The catalytic decomposition of C2H4 on Ni/GLM at temperatures of 500–700 °C leads to the formation of CNF on the surface of the GLM, and the decomposition of CH4 at 900 °C – with the formation of CNT. The CNT and CNF formed have a diameter in the range from 5 to 20 nm, and the length increases from 5 to 300 nm with rise of synthesis duration. Such three-dimensional structures have a high specific surface area and are attractive as sorbents of gases and carriers of metal catalysts.Forcitation:Tarasov B.P., Arbuzov A.A., Volodin A.A., Mozhzhukhin S.A., Klyuev M.V. Nickel-graphene catalyst for magnesium hydrogenation and for carbon nanostructures synthesis. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 43-46.

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Muntean, Roxana, Ulrich Rost, Gabriela Marginean, and Nicolae Vaszilcsin. "Optimisation of the Electrodeposition Parameters for Platinum Nanoparticles on Carbon Nanofibers Support." Solid State Phenomena 254 (August 2016): 153–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.254.153.

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Platinum nanoparticles electrodeposition on carbon nanofibers (CNF) support has been performed with the purpose to obtain electrodes that can be further used especially in a polymer electrolyte membrane fuel cell (PEMFC). A pretreatment of CNF is required in order to enhance the surface energy, which simultaneously improves handling and wettability as well as interaction with the platinum cations. This step was performed using oxygen plasma functionalization. To produce CNF supported Pt catalysts, an electrochemical method was applied and the deposition parameters were adjusted to obtain nanosized platinum particles with a good distribution onto the graphitic surface. The morphology and structure of the obtained particles were investigated by scanning electron microscopy combined with energy dispersive X-Ray spectroscopy. The amount of deposited platinum was established using thermogravimetrical measurements. Cyclic voltammetry performed in 0.5 M H2SO4 solution was applied for determining the electrochemical surface area (ECSA) of the obtained electrodes.The functionalization degree of the CNF outer surface has a strong influence on the structure, distribution and amount of platinum particles. Moreover, the current densities, which were set for the deposition process influenced not only the particles size but also the platinum amount. Applying an oxygen plasma treatment of 80 W for 1800 s, the necessary degree of surface functionalization is achieved in order to deposit the catalyst particles. The best electrodes were prepared using a current density of 50 mA cm-2 during the deposition process that leads to a homogenous platinum distribution with particles size under 80 nm and ECSA over 6 cm2.

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Yaldagard, Maryam, Mariyeh Nazoktabar, and Mohsen Jahanshahi. "Fabrication of Platinum/ Polypyrol-Carbon Nanofiber Nanocomposite Electrocatalyst for Direct Methanol Fuel Cells." Journal of Nano Research 70 (October 25, 2021): 101–17. http://dx.doi.org/10.4028/www.scientific.net/jnanor.70.101.

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A novel electrocatalyst has been developed based on polypyrol-carbon nanofiber (PPy-CNF) support material to increase the stability of Pt/ PPy-CNF/GDL electrocatalyst in direct methanol fuel cell (DMFC). A novel conducting polymer (PPy)-CNF nanocomposites was prepared by a solution dispersion technique and used to support platinum nanoparticles. For preparation of catalyst ink, 20 wt.% Pt/PPy-CNF electrocatalyst with a platinum loading of 0.4 mg cm-2 was prepared by ethylene glycol (EG) method. Physical and electrochemical properties were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) imaging and cyclic voltammetry (CV) experiments. FTIR results prove the existence of PPy in the support. SEM images showed that the one–dimensional CNFs were efficaciously covered by PPy. The TEM characterization revealed that the fine Pt nanoparticles prepared by polyol method were dispersed on the surface of the electrocatalyst successfully. XRD patterns also revealed that the mean size of Pt crystal nanoparticles was about 3.69, 6.51 and 2.91 nm for Pt/PPy-CNF, Pt/CNF and Pt/C electrocatalyst respectively. The size of the PPy on carbon paper has been measured in the range of 35-40nm by AFM. Based on the electrochemical properties and acceleration tests evaluated by cyclic voltammetry measurements and Chronoamperometric experiments it was found that the as prepared Pt/PPy-CNF/GDL electrode exhibited a comparable electrochemical surface are (ECSA), MOR activity and so stability (in the presence of methanol) with respect to the Pt/CNF /GDL and Pt/C/GDL commercial one. A rather significant reduction in the peak potential of methanol electro-oxidation from 0.69V for Pt/C/GDL to 0.76V for Pt/PPy-CNF/GDL electrode indicates that an increase in the activity for MOR is achieved by replacing the C by PPy-CNF. The corresponding ECSA values for the Pt/PPy-CNF/GDL, Pt/CNF/GDL and Pt/C/GDL electrodes were 108.69, 53.93 and 17.98 m2g-1 respectively.

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Landge, Vividha K., Vikas S. Hakke, Manohar Kakunuri, G. Uday B. Babu, Grzegorz Boczkaj, and Shirish H. Sonawane. "Synthesis of bimetallic Co–Pt/cellulose nanocomposites for catalytic reduction of p-nitrophenol." Reaction Chemistry & Engineering 7, no. 3 (2022): 641–52. http://dx.doi.org/10.1039/d1re00422k.

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The sonochemical synthesis of Co–Pt nanoparticles anchored on cellulose nanofibers (CNFs) was demonstrated. An enhancement in the catalytic activity of the synthesized Co–Pt/CNF nanocomposite catalyst was observed for the reduction of p-NP due to synergy effects.

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Ghamari Kargar, Pouya, and Ghodsieh Bagherzade. "Robust, highly active, and stable supported Co(ii) nanoparticles on magnetic cellulose nanofiber-functionalized for the multi-component reactions of piperidines and alcohol oxidation." RSC Advances 11, no. 38 (2021): 23192–206. http://dx.doi.org/10.1039/d1ra00208b.

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The new recyclable cobalt three-core magnetic catalyst obtained by anchoring a Schiff base ligand sector and cellulose nanofiber slings on MNP (Fe₃O₄) was prepared and named as MNP@CNF@ATSM–Co(ii).

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Moreira, Rui, Elba Ochoa, José Pinilla, António Portugal, and Isabel Suelves. "Liquid-Phase Hydrodeoxygenation of Guaiacol over Mo2C Supported on Commercial CNF. Effects of Operating Conditions on Conversion and Product Selectivity." Catalysts 8, no. 4 (March 22, 2018): 127. http://dx.doi.org/10.3390/catal8040127.

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In this work, a Mo2C catalyst that was supported on commercial carbon nanofibers (CNF) was synthetized and tested in the hydrodeoxygenation (HDO) of guaiacol. The effects of operating conditions (temperature and pressure) and reaction time (2 and 4 h) on the conversion of guaiacol and products selectivity were studied. The major reaction products were cresol and phenol, followed by xylenols and toluene. The use of more severe operating conditions during the HDO of guaiacol caused a diversification in the reaction pathways, and consequently in the selectivity to products. The formation of phenol may have occurred by demethylation of guaiacol, followed by dehydroxylation of catechol, together with other reaction pathways, including direct guaiacol demethoxylation, and demethylation of cresols. X-ray diffraction (XRD) analysis of spent catalysts did not reveal any significant changes as compared to the fresh catalyst.

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Pedram, Sara, and Jasna Jankovic. "Fabrication and Performance Evaluation of Tubular Catalyst Layer for Proton Exchange Membrane Fuel Cell." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1429. http://dx.doi.org/10.1149/ma2022-01351429mtgabs.

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Over the past several decades, planar proton exchange membrane fuel cells (PEMFCs) received considerable attention due to their simple structure, manufacturing, and easy integration. However, current PEMFC electrode designs are disadvantaged by high cost, insufficient mass transport, nonuniform reactant, current and temperature distribution, and limited water removal. The development of a novel tubular fuel cell design could address these challenges. Tubular-shaped PEMFC offers several advantages over planar one, including lower pressure drop, efficient water removal, reduced mass transport losses, and cost reduction owing to removing one of gas diffusion layer/bipolar plate (GDL/BPP) side. This work developed a carbon nanofiber (CNF)/Pt-based cathode for a tubular fuel cell. The tubular CNF support for Pt catalyst was fabricated employing the electrospinning method. Polyacrylonitrile (PAN) was used as the precursor. The electroless deposition of Pt using the chloroplatinic acid solutions was applied to produce well-dispersed low Pt loading nanowires. The tubular CNF/Pt electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), ex-situ cyclic voltammetry to determine the CF and Pt morphology and feasibility of the prepared layer in PEMFC application. SEM images indicated that increasing the Pt precursor concentration in the plating bath leads to higher Pt loading and larger Pt clusters on the CNF surface. The calculated electrochemical active surface area (ECSA) trend imparts that high Pt loading is less favorable as thick Pt layers lead to low Pt utilization and increased material costs. ECSA results agreed with SEM images, suggesting that the medium Pt concentration (1.5 g L-1 Pt precursor) developed a homogenous Pt distribution and comparable Pt surface area of 24 m2 gPt -1 for the Pt loading of 0.046 mg cm-2, proving the feasibility of the proposed process.

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Kasi, Jafar Khan, Ajab Khan Kasi, Winadda Wongwiriyapan, Nitin Afzulpurkar, Paweena Dulyaseree, Mahadi Hasan, and Adisorn Tuantranont. "Synthesis of Carbon Nanotube and Carbon Nanofiber in Nanopore of Anodic Aluminum Oxide Template by Chemical Vapor Deposition at Atmospheric Pressure." Advanced Materials Research 557-559 (July 2012): 544–49. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.544.

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Carbon nanotube (CNT) is one of the most attractive materials for the potential applications of nanotechnology due to its excellent mechanical, thermal, electrical and optical properties. We demonstrated the fabrication of carbon nanotube and carbon nanofiber (CNF) inside the pore and at the surface of anodic aluminum oxide (AAO) membrane by chemical vapor deposition method at atmospheric pressure. Ethanol was used as a hydrocarbon source and Co–Mo as catalyst. CNT was synthesized at different temperature. High graphitic multiwall carbon nanotube (MWCNT) was found at 750°C, while CNF was found at 800°C and above temperature analyzing by Raman spectroscopy.

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Barhoum, Ahmed, Therese Favre, Syreina Sayegh, Fida Tanos, Emerson Coy, Igor Iatsunskyi, Antonio Razzouk, Marc Cretin, and Mikhael Bechelany. "3D Self-Supported Nitrogen-Doped Carbon Nanofiber Electrodes Incorporated Co/CoOx Nanoparticles: Application to Dyes Degradation by Electro-Fenton-Based Process." Nanomaterials 11, no. 10 (October 12, 2021): 2686. http://dx.doi.org/10.3390/nano11102686.

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We developed free-standing nitrogen-doped carbon nanofiber (CNF) electrodes incorporating Co/CoOx nanoparticles (NPs) as a new cathode material for removing Acid Orange 7 (AO7; a dye for wool) from wastewater by the heterogeneous electro-Fenton reaction. We produced the free-standing N-doped CNF electrodes by electrospinning a polyacrylonitrile (PAN) and cobalt acetate solution followed by thermal carbonation of the cobalt acetate/PAN nanofibers under a nitrogen atmosphere. We then investigated electro-Fenton-based removal of AO7 from wastewater with the free-standing N-doped-CNFs-Co/CoOx electrodes, in the presence or not of Fe2+ ions as a co-catalyst. The electrochemical analysis showed the high stability of the prepared N-doped-CNF-Co/CoOx electrodes in electrochemical oxidation experiments with excellent degradation of AO7 (20 mM) at acidic to near neutral pH values (3 and 6). Electro-Fenton oxidation at 10 mA/cm2 direct current for 40 min using the N-doped-CNF-Co/CoOx electrodes loaded with 25 wt% of Co/CoOx NPs led to complete AO7 solution decolorization with total organic carbon (TOC) removal values of 92.4% at pH 3 and 93.3% at pH 6. The newly developed N-doped-CNF-Co/CoOx electrodes are an effective alternative technique for wastewater pre-treatment before the biological treatment.

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Malara, Angela, Emilia Paone, Lucio Bonaccorsi, Francesco Mauriello, Anastasia Macario, and Patrizia Frontera. "Pd/Fe3O4 Nanofibers for the Catalytic Conversion of Lignin-Derived Benzyl Phenyl Ether under Transfer Hydrogenolysis Conditions." Catalysts 10, no. 1 (December 22, 2019): 20. http://dx.doi.org/10.3390/catal10010020.

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Novel magnetite-supported palladium catalysts, in the form of nanofiber materials, were prepared by using the electrospinning process. Two different synthetic techniques were used to add palladium to the nanofibers: (i) the wet impregnation of palladium on the Fe3O4 electrospun support forming the Pd/Fe3O4[wnf] catalyst or (ii) the direct co-electrospinning of a solution containing both metal precursor specimens leading to a Pd/Fe3O4[cnf] sample. The obtained Pd-based Fe3O4 nanofibers were tested in the transfer hydrogenolysis of benzyl phenyl ether (BPE), one of the simplest lignin-derived aromatic ethers, by using 2-propanol as H-donor/solvent, and their performances were compared with the analogous impregnated Pd/Fe3O4 catalyst and a commercial Pd/C. A morphological and structural characterization of the investigated catalysts was performed by means of SEM-EDX, TGA-DSC, XRD, TEM, H2-TPR, and N2 isotherm at 77 K analysis. Pd/Fe3O4[wnf] was found to be the best catalytic system allowing a complete BPE conversion after 360 min at 240 °C and a good reusability in up to six consecutive recycling tests.

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Lázaro, M. P., E. García-Bordejé, D. Sebastián, M. J. Lázaro, and R. Moliner. "In situ hydrogen generation from cycloalkanes using a Pt/CNF catalyst." Catalysis Today 138, no. 3-4 (November 2008): 203–9. http://dx.doi.org/10.1016/j.cattod.2008.05.011.

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Koskin, Anton P., Roman V. Kenzhin, Aleksey A. Vedyagin, and Ilya V. Mishakov. "Sulfated perfluoropolymer–CNF composite as a gas-phase benzene nitration catalyst." Catalysis Communications 53 (August 2014): 83–86. http://dx.doi.org/10.1016/j.catcom.2014.04.026.

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Liu, Meng Ying, Ya Li Li, Sheng Xiang Qu, Shuai Shuai Han, and Si Hui Wang. "Fabrication of Carbon Nanofiber and Silicon Carbonitride Ceramic Nanomposites by In Situ Growth during Ceramic Formation." Key Engineering Materials 602-603 (March 2014): 221–25. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.221.

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Carbon nanofiber (CNF) and silicon carbonitride (SiCN) ceramic nanocomposites (SiCN/CNF) are fabricated by in-situ growth of CNFs in SiCN ceramics during ceramic transformation of polymeric precursors of polysilazanes (PSZ). Metal catalyst precursors are mixed into the polysilazane liquid forming metal particles from decomposition under heating during the pyrolysis. At certain temperatures, ethylene was introduced as a carbon source to induce the growth of CNFs over the metal particles in the ceramic body followed by heating to higher temperatures to complete the pyrolysis. In this way, bulk nanocomposites of SiCN/CNF are obtained as crack-free bodies although some pores are left in the sample. Scanning electron microscopy (SEM) analysis performed on the cross-section of nanocomposites revealed the distribution of needle-like nanofibers of diameter ~ 200 nm and exposed length of ~ 2 μm. The CNFs exhibited the unique multiscale nanostructure in micron hollow tubes with branched nanofiber walls. Energy dispersive X-ray spectrometer (EDX) detected carbon as the major element from the nanofibers confirming the formation of carbon nanofibers. Moreover, clusters of nanoparticles are formed on the ceramic surface from carbon depositions. The in-situ growth of CNFs in SiCN ceramics provides a one-step process potentially to be developed for fabrication of structural and functional SiCN/CNF nanocomposites.

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Mohamed Aslam, Norraihanah, Takuya Tsujiguchi, Yugo Osaka, and Akio Kodama. "The Origins of the High Performance of Pd Catalysts Supported on Carbon Black-Embedded Carbon Nanofiber for Formic Acid Oxidation." Applied Sciences 9, no. 24 (December 16, 2019): 5542. http://dx.doi.org/10.3390/app9245542.

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In this study, we developed a carbon black (CB)-embedded carbon nanofiber (CNF) as a Pd support, which showed a high level of formic acid oxidation reaction (FAOR) activity. For the support preparation, heat treatment involving calcination at 1000 °C in a nitrogen atmosphere (carbonization) followed by calcination at 850 °C in water vapor (steam activation) was conducted to form a CB, which contained carbon nanofibers made from a polyacrolynitrile (PAN) fiber prepared by electrospinning. This catalyst showed a high level of FAOR activity. In this situation, the CB was also heat-treated, therefore, it was unclear whether the origin of the high FAOR activity of the CB-embedded CNF was caused by the CNF itself or the heat treatment of the CB. In order to establish the cause of the high FAOR activity of the CB-embedded CNF, the CBs underwent several heat treatments; i.e., stabilization, carbonization, and steam activation. Two types of carbon black with different pore structures, i.e., Ketjen black and Vulcan XC-72, were used to investigate the FAOR activity. The appropriate heat treatment of the CB promotes the improved FAOR activity; however, excessive heat treatment caused a deterioration in the FAOR activity, especially for Ketjen due to the presence of numerous micropores. However, by embedding the CB into the CNF, the FAOR activity improved, especially in the case of Ketjen, even though the embedded CB underwent several heat treatments. The optimum ratio of CB/PAN in the CB-embedded CNF was also investigated. The highest FAOR activity was observed at 0.25 CB/PAN for both the Vulcan and Ketjen. The electronic state of Pd3d in which the binding energy of the metallic Pd shifted to a lower binding energy suggested that the metal–support interaction is strong at the CB/PAN ratio of 0.25. On the basis of these results, it was found that heat treatment of the CB by embedding it in the CNF is a promising way to achieve a metal–support interaction without destroying its structure.

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Jung, Juhae, Byungil Park, and Junbom Kim. "Durability test with fuel starvation using a Pt/CNF catalyst in PEMFC." Nanoscale Research Letters 7, no. 1 (2012): 34. http://dx.doi.org/10.1186/1556-276x-7-34.

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Tovini, Mohammad Fathi, Bhushan Patil, Cevriye Koz, Tamer Uyar, and Eda Yılmaz. "Nanohybrid structured RuO2/Mn2O3/CNF as a catalyst for Na–O2 batteries." Nanotechnology 29, no. 47 (September 26, 2018): 475401. http://dx.doi.org/10.1088/1361-6528/aadfb7.

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Vengust, Damjan, Mojca Vilfan, and Aleš Mrzel. "Growth of carbon nanofibres on molybdenum carbide nanowires and their self-decoration with noble-metal nanoparticles." Royal Society Open Science 7, no. 9 (September 2020): 200783. http://dx.doi.org/10.1098/rsos.200783.

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High specific surface area makes carbon nanofibres suitable for catalyst support. Here we report on optimization of carbon nanofibre (CNF) growth on molybdenum carbide nanowires (MoCNW) by direct carburization of Mo 6 S 2 I 8 nanowire bundles. Typical CNFs obtained by this method are several hundreds of nanometres long at a diameter of 10–20 nm. We show that nanofibre growth does not depend on the initial morphology of the nanowires: nanofibres grow on individual bundles of MoCNW, on dense networks of nanowires deposited on silicon substrate, and on free-standing nanowire foils. We find that carbon nanofibres remain firmly attached to the nanowires even if they are modified into Mo 2 C and further into Mo S 2 nanowires. The method thus enables production of a novel hybrid material composed of Mo S 2 nanowires densely covered with carbon nanofibres. We have additionally shown that the obtained CNFs can easily be self-decorated with platinum nanoparticles with diameters of several nanometres directly from water solution at room temperature without reducing agents. Such efficient synthesis and decoration process yield hybrid platinum/CNF/molybdenum-based NW materials, which are a promising material for a wide range of possible future applications, including sensitive sensorics and improved catalysis.

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Xu, Xian Feng, Yan Yan Hu, and Peng Xiao. "The Morphologies of Nano Carbon Growing In Situ by Catalytic Chemical Vapor Deposition." Advanced Materials Research 430-432 (January 2012): 1269–72. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1269.

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In order to improve surface characteristics of carbon fibers, using nickel granules as catalysts, nano carbon with different morphologies was deposited in-situ on the surface of carbon fibers by the method of Chemical Vapor Deposition (CVD). The observations by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) indicated that keeping the excellent performance of plating nickels catalyst and a suitable deposition rate of Pyrogenation Carbon (PyC) are the key factors for getting Carbon Nanotube and Carbon Nanofiber (CNT/CNF). In this experiment, the optimum operation conditions are: plating time at 5min, deposition temperature at 1173K, deposition time at 2 hours, flow of C3H6, H2 and N2 at 30, 200 and 400ml/min respectively, deposition pressure at 700-1000Pa. Evolution rules of nano carbon are explained in growth mechanism of Catalytic Chemical Vapor Deposition (CCVD).

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Jia, Mingming, and Yongheng Zhang. "Study on the synthesis of carbon fibers and CNF using potassium iodide catalyst." Materials Letters 63, no. 24-25 (October 2009): 2111–14. http://dx.doi.org/10.1016/j.matlet.2009.07.004.

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Huang, Bo-Wen, Lei Li, Yi-Jun He, Xiao-Zhen Liao, Yu-Shi He, Weiming Zhang, and Zi-Feng Ma. "Enhanced Electrochemical Performance of Nanofibrous CoO/CNF Cathode Catalyst for Li-O2 Batteries." Electrochimica Acta 137 (August 2014): 183–89. http://dx.doi.org/10.1016/j.electacta.2014.05.114.

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Fernández, Adolfo, Pavel Peretyagin, Washington Solís, Ramón Torrecillas, and Amparo Borrell. "Functionalization of Carbon Nanofibres Obtained by Floating Catalyst Method." Journal of Nanomaterials 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/395014.

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The excellent physicochemical and electrical properties of carbon nanofibres (CNF) combined with the possibility of being produced at industrial scale at reasonable costs have promoted the interest in their use in very diverse areas. However, there are still some drawbacks that must be solved in order to optimize their set of properties such as the presence of impurities or the imperfections in the crystalline structure. In this work, different modification treatments of CNFs produced by the floating catalyst method have been studied. Three types of modification processes have been explored that can be grouped as mechanical, thermal, and chemical functionalization processes. Mechanical processing has allowed solving the agglomeration problem related to CNFs produced by floating catalyst method and the resulting modified product ensures the secure handling of carbon nanofibres. Thermal and chemical treatments lead to purer and more crystalline products by removing catalyst impurities and amorphous carbon. Functionalization processes explored in this work open the possibility of customized posttreatment of carbon nanofibres according to the desired requirements.

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Lee, Jaesung, Philip X. L. Feng, and Anupama B. Kaul. "Characterization of Plasma Synthesized Vertical Carbon Nanofibers for Nanoelectronics Applications." MRS Proceedings 1451 (2012): 117–22. http://dx.doi.org/10.1557/opl.2012.922.

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ABSTRACTWe report on the material characterization of carbon nanofibers (CNFs) which are assembled into a three-dimensional (3D) configuration for making new nanoelectromechanical systems (NEMS). High-resolution scanning electron microscopy (SEM) and x-ray electron dispersive spectroscopy (XEDS) are employed to decipher the morphology and chemical compositions of the CNFs at various locations along individual CNFs grown on silicon (Si) and refractory nitride (NbTiN) substrates, respectively. The measured characteristics suggest interesting properties of the CNF bodies and their capping catalyst nanoparticles, and growth mechanisms on the two substrates. Laser irradiation on the CNFs seems to cause thermal oxidation and melting of catalyst nanoparticles. The structural morphology and chemical compositions of the CNFs revealed in this study should aid in the applications of the CNFs to nanoelectronics and NEMS.

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Azara, Abir, El-Hadi Benyoussef, Faroudja Mohellebi, Mostafa Chamoumi, François Gitzhofer, and Nicolas Abatzoglou. "Catalytic Dry Reforming and Cracking of Ethylene for Carbon Nanofilaments and Hydrogen Production Using a Catalyst Derived from a Mining Residue." Catalysts 9, no. 12 (December 14, 2019): 1069. http://dx.doi.org/10.3390/catal9121069.

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In this study, iron-rich mining residue (UGSO) was used as a support to prepare a new Ni-based catalyst via a solid-state reaction protocol. Ni-UGSO with different Ni weight percentages wt.% (5, 10, and 13) were tested for C2H4 dry reforming (DR) and catalytic cracking (CC) after activation with H2. The reactions were conducted in a differential fixed-bed reactor at 550–750 °C and standard atmospheric pressure, using 0.5 g of catalyst. Pure gases were fed at a molar ratio of C2H4/CO2 = 3 for the DR reaction and C2H4/Ar = 3 for the CC reaction. The flow rate is defined by a GHSV = 4800 mLSTP/h.gcat. The catalyst performance is evaluated by calculating the C2H4 conversion as well as carbon and H2 yields. All fresh, activated, and spent catalysts, as well as deposited carbon, were characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), temperature programmed reduction (TPR), and thermogravimetric analysis (TGA). The results so far show that the highest carbon and H2 yields are obtained with Ni-UGSO 13% at 750 °C for the CC reaction and at 650 °C for the DR reaction. The deposited carbon was found to be filamentous and of various sizes (i.e., diameters and lengths). The analyses of the results show that iron is responsible for the growth of carbon nanofilaments (CNF) and nickel is responsible for the split of C–C bonds. In terms of conversion and yield efficiencies, the performance of the catalytic formulations tested is proven at least equivalent to other Ni-based catalyst performances described by the literature.

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Torres, Daniel, José Pinilla, and Isabel Suelves. "Co-, Cu- and Fe-Doped Ni/Al2O3 Catalysts for the Catalytic Decomposition of Methane into Hydrogen and Carbon Nanofibers." Catalysts 8, no. 8 (July 27, 2018): 300. http://dx.doi.org/10.3390/catal8080300.

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The catalytic decomposition of methane (CDM) process produces hydrogen in a single stage and avoids CO2 emission thanks to the formation of high added value carbon nanofilaments as a by-product. In this work, Ni monometallic and Ni–Co, Ni–Cu, and Ni–Fe bimetallic catalysts are tested in the CDM reaction for the obtention of fishbone carbon nanofibers (CNF). Catalysts, in which Al2O3 is used as textural promoter in their formulation, are based on Ni as main active phase for the carbon formation and on Co, Cu, or Fe as dopants in order to obtain alloys with improved catalytic behaviour. Characterization of bimetallic catalysts showed the formation of particles of Ni alloys with a bimodal size distribution. For the doping content studied (5 mol. %), only Cu formed an alloy with a lattice constant high enough to be able to favor the carbon diffusion through the catalytic particle against surface diffusion, resulting in higher carbon formations, longer activity times, and activity at 750 °C; whereas Ni, Ni–Co, and Ni–Fe catalysts were inactive. On the other hand, Fe also improved the undoped catalyst performance presenting a higher carbon formation at 700 °C and the obtention of narrow carbon nanofilaments from active Ni3Fe crystallites.

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Soundararajan, D., J. H. Park, K. H. Kim, and J. M. Ko. "Pt–Ni alloy nanoparticles supported on CNF as catalyst for direct ethanol fuel cells." Current Applied Physics 12, no. 3 (May 2012): 854–59. http://dx.doi.org/10.1016/j.cap.2011.11.020.

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Journal articles on the topic 'CNF catalyst'

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