Synthesis Of Nanostructured Carbon Materials Research Articles

Ultraviolet light–assisted synthesis of nanostructured carbon materials for supercapacitor electrodes by using zinc oxide structures as template and catalyst

Ultraviolet light–assisted synthesis of nanostructured carbon materials for supercapacitor electrodes by using zinc oxide structures as template and catalyst

Tunable 1D and 2D Polyacrylonitrile Nanosheet Superstructures.

Carbon superstructures are widely applied in energy and environment-related areas. Among them, the flower-like polyacrylonitrile (PAN)-derived carbon materials have shown great promise due to their high surface area, large pore volume, and improved mass transport. In this work, we report a versatile and straightforward method for synthesizing one-dimensional (1D) nanostructured fibers and two-dimensional (2D) nanostructured thin films based on flower-like PAN chemistry by taking advantage of the nucleation and growth behavior of PAN. The resulting nanofibers and thin films exhibited distinct morphologies with intersecting PAN nanosheets, which formed through rapid nucleation on existing PAN. We further constructed a variety of hierarchical PAN superstructures based on different templates, solvents, and concentrations. These PAN nanosheet superstructures can be readily converted to carbon superstructures. As a demonstration, the nanostructured thin film exhibited a contact angle of ∼180° after surface modification with fluoroalkyl monolayers, which is attributed to high surface roughness enabled by the nanosheet assemblies. This study offers a strategy for the synthesis of nanostructured carbon materials for various applications.

Super microporous sulfur-doped hard carbon synthesized from a π-stacked Polybenzo[c]thiophene boosting reversible lithium-ion insertion at room temperature

Synthesis of porous carbon materials with controlled textural properties is an all-time challenging process for energy storage applications. Aromatic polymers possess high rigidity due to their π-π stacking arrangement and could serve as robust precursors to produce porous carbon. Herein, super-microporous sulfur-doped hard carbons (SM-SDHCs) were synthesized from a highly ordered aromatic polybenzo[c]thiophene between 600 and 800 °C by using KOH as an activation agent. The degree of carbonization and defects were enhanced as the temperature increased from 600 to 800 °C as confirmed by X-ray diffraction and Raman spectroscopy techniques. All the SM-SDHCs exhibit a super-microporosity (<2 nm) and high surface area (1126–1444 m2 g−1). Among the three synthesized carbons, the SM-SDHC800 exhibited a high discharge capacity of 760.7 mAh g−1 at 20 mA g−1 and showed excellent cycle stability at 200 mA g−1 for 250 cycles. The reversible lithium-ion insertion of SM-SDHC800 anode is accredited to its high degree of carbonization, defect-rich quality, high interlayer distance, and microporous texture with large pore volume (0.68 cm3 g−1). In addition, the excellent cycle stability at 2 A g−1 for 1000 cycles shows its robustness for high C-rate LIBs. Polybenzo[c]thiophene precursor is a perceptive choice to produce sulfur-doped super-microporous hard carbon with controlled textural properties and could bring dramatic advances in the synthesis of nanostructured carbon materials for energy storage applications.

Facile synthesis of multidimensional nanoscaled-carbon via simplified arc underwater: An integrated process for 0-D, 1-D and 2-D

An adaptable and simplified arc underwater set-up is designed for synthesis of nanostructured carbon materials (NSCM) such as carbon onions (CO), multi-walled carbon nanotubes (MWCNTs) and nanoscale graphitic carbon (NGC). Essentially, the set-up consists of a DC power supply, two graphite electrodes and a container for de-ionized water storage. Transmission electron microscopic analysis confirmed that the cathode deposit, floating particles and settled materials consist of MWCNTs, CO and NGC, respectively. The kind of NSCM formation is critically governed by temperature gradient and cooling rate created due to bubble collapse in nucleate boiling during the arcing process. Based on the anode consumption, the total yield of the carbon materials is about ∼25.5 wt% which consists 5 wt% of FP, 8.5 wt% of CD and remaining 12 wt% of SP. FP, CD, and SP presented crystallite size of 23.69 nm, 11.84 nm, and 28.91 nm, respectively. The high rate and moderate rate of cooling will determine the growth of MWCNTs and CO, respectively. NGC exhibited specific capacity of 325 mAhg−1 with lithium half-cell after 50 cycles at a current density of 100 mAg−1.

Synthesis of nanostructured carbon materials with different morphology of aggregates and their sorption properties with respect to nickel(II) ions

Efficient methods for the synthesis of carbon nanostructures with high specific surface area and controlled morphologies are crucial for their use in various applications. Here, we report a low-temperature precursor method for the synthesis of nanostructured carbon materials and show how the aggregate morphology and the specific surface area of isolated carbon materials depend on the composition, synthesis conditions and chemical nature of the precursor. Complex zinc compounds (carboxylates, alkoxides), capable of a pseudomorphic transformation into composites of the general composition ZnO:nC during heating in an inert gaseous medium, were used as precursors. The ZnO nanoparticles (10–15 nm) were washed from the composites by diluted formic acid. The obtained carbon materials exhibit different morphologies and specific surface areas up to 1706 m2/g. For two synthesized carbon materials, their sorption properties with respect to nickel(II) ions were studied. It was found that these materials, despite the differences in the morphology and specific surface areas of their particles, have the same sorption capacity with respect to nickel ions. Sorption has a physical nature and is well described by the Langmuir isotherm.

One-pot synthesis of nanostructured carbon materials from carbon dioxide via electrolysis in molten carbonate salts

As the primary culprit of greenhouse effect, carbon dioxide has garnered global attention, and the technologies currently being developed to reduce the emission of CO2 vary widely. In this study, CO2 was electrochemically reduced in various molten mixtures of LiNaK carbonates to carbon nanomaterials. By regulating the electrolysis current density, electrolyte, and electrolytic temperature, the carbon products had different morphologies of honeycomb-like and nanotubular structures. A transition from a honeycomb/platelet to nanomaterial carbon morphology was observed to occur at ∼600 °C with increase in temperature. The observation of nanostructures is consistent with a higher diversity of structures possible with enhanced rearrangement kinetics that can occur at higher temperature. A high yield of a carbon nanotube (CNT) was not observed from a LiNaK electrolyte, no CNTs are formed from a NaK carbonate electrolyte, but a high yield is observed from pure Li, or mixed LiNa or mixed LiBa carbonate electrolytes, and the carbon nanotube product diameter is observed to increase with increasing electrolysis time.

Effect of ultrasound on a mixed oxide-based catalyst for synthesis of nanostructured carbon materials

The effect of ultrasonic activation on the performance of a mixed oxide-based (Ni/Mg) catalyst in the synthesis of multiwalled carbon nanotubes via chemical vapor deposition was studied. The molecular geometry of the solution of initial catalyst components (feed solution) was calculated and simulated according to a molecular mechanics method. Activation of the catalyst performed for 10 s during its preparation stage resulted in a considerable increase (of about 40 %) in the specific yield of nanotubes due to enhanced catalytic activity. Moreover, the kinetics of nanotube synthesis over the activated catalyst was studied, and the morphology of the obtained nanoproduct was investigated. Finally, the possibility of employing the present method for catalyst activation in experimental–industrial production of nanotubes was evaluated.

Synthesis of multi-layer graphene and multi-wall carbon nanotubes from direct decomposition of ethanol by microwave plasma without using metal catalysts

The synthesis of nanostructured carbon materials by using microwave plasmas at atmospheric pressure is presented. This technique involves only one step and without any other supplementary chemical process or metal catalyst. Multi-layer graphene, multi-wall carbon nananotubes and H2 were obtained by the plasma after ethanol decomposition. Strong emissions of both C2 molecular bands and C carbon were emitted by the plasma during the process. Futhermore, plasma parameters were studied. Our research shows that both C2 radicals and high gas temperatures (>3000 K) are required for the synthesis of these materials, which contribute to the understanding of materials synthesis by plasma processes.

Synthesis of Nanostructured Carbon Materials on a Tin Thin Film Using Phenol Formaldehyde as the Carbon Source

Nanostructured carbon materials were successfully synthesized on a tin thin film using a commercially available paper phenolic (PP) board, which is composed mainly of phenol formaldehyde (PF), as the carbon source. The heating source for thermal decomposition of PF is a current-stressed Cu trace which was patterned on the PP board near the tin thin film. The tin thin film was deposited on the PP board near the Cu trace using evaporation. During thermal treatment, nanostructured carbon materials were formed on the tin thin film. The synthesized products contain carbon nanosheets and tubular carbon nanofibers (CNFs) in which the former was formed near the heating Cu trace and the latter was found at a more distant location. A potential mechanism for the formation of nanostructured carbon materials is also discussed.

Use of a pulsating combustion apparatus to obtain a catalyst for the synthesis of nanostructured carbon materials

The preparation of highly efficient catalysts for the synthesis of nanostructured carbon-based nanostructured materials is considered. Catalysts of the NiO/MgO type with nanosized active sites can be obtained by burning the initial aqueous solution of nickel and magnesium nitrates with glycine in a pulsating combustion apparatus. Based on an analysis of features of the pulsating gas flow in elements of such apparatuses, a scheme has been developed and a setup has been created for the continuous synthesis of catalysts. Results of investigation of a carbon-based material synthesized on the proposed catalyst are presented.