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A study of polyaromatic hydrocarbons by semiempirical PM3 and ab initio methods in MINI and STO 6G-31 bases has been performed for compounds with different numbers of rings. The optimized space and electronic structures have been derived. The multiplicity states effect on the energetic stability of the polyaromatic hydrocarbons is examined. It is shown that the high multiplicity states become more energetically preferable with the growth of the PAH size.

Interaction of the previously described [V. D. Khavryuchenko, Y. A. Tarasenko, V. V. Strelko, O. V. Khavryuchenko and V. V. Lisnyak, Quantum chemical study of polyaromatic hydrocarbons in high multiplicity states, Int. J. Modern. Phys. B21, 4507 (2007), in press] polyaromatic hydrocarbon (PAH) C₉₆H₂₄ with dioxygen molecule and KO₂ have been quantum chemically examined. The probability of existence of the oxygen superoxide ion-radical O₂ adsorbed on the surface of the PAH is critically discussed.

In this paper, we report the growth of carbon nanofibers (CNFs) by catalyst-free ultrasonic spray-pyrolysis of methanol, ethanol and 2-propanol. We found that the morphology of carbon deposition on the substrate strongly depended on the position of the substrate in the reaction tube and the carbon source species. When ethanol and 2-propanol were used as the carbon source, a slightly hollow structure CNFs were formed downstream in the reaction tube, whereas when the carbon source was methanol, an amorphous structure CNFs were formed at the center of the reaction tube. We consider the difference in CNFs growth between the alcohol types is presence of alkyl groups in alcohol.

Metal oxide-carbon composites (MOCCs) derived from sodium alginate gels were prepared through a facile and green ionic gelation method. Various polyvalent cations (Mn${}^{2+}$, Fe${}^{3+}$, and Zn${}^{2+})$ were used to crosslink sodium alginate to produce gels, following which the gels were carbonized under nitrogen flow to yield MOCCs. X-ray diffraction, scanning electron microscopy, and Raman spectra can character the as-prepared materials’ structural and morphological characters and thermogravimetric analysis. The electrochemical behavior of the as-prepared materials was studied by applying to cyclic voltammetry, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy in 6M KOH electrolyte. The highest specific capacitance (161F g${}^{-1}$ at 0.5A g${}^{-1})$ was obtained for the Fe oxide-doped carbon material (MOCC-Fe), which displayed a good life cycle with only a 10% capacitance decline after 2000 cycles.

Carbon materials are well known for their excellent adsorbent property towards gases. Much work has been done to improve the properties of carbon materials as to enhance their absorption capacity towards gases. Recent developments have resulted in the discovery of novel carbon materials such as carbon nanotubes. Numerous researches have shown that carbon nanotubes have excellent capacity for hydrogen storage. However, significant research has been undertaken to further improve the adsorption capacity through the advancement in synthesis methods for the fabrication of carbon nanotubes. Among the starting material widely employed for synthesis of carbon nanotubes is high purity graphite. Therefore, purpose of this work is to investigate the effect of thermal treatment on several synthetic graphites. Thermal treatment was conducted at temperatures ranging from 400–800°C at different dwelling times. The morphology and surface analysis of the graphites were examined using Scanning Electron Microscope and nitrogen gas adsorption techniques, respectively. It was found that temperature, time and conditions of treatment significantly change the surface structure of the graphites. A decrease in particle size was observed due to the release of internal surface area.

Carbon nanodots (C-dots), as a class of heavy-metal-free fluorescent nonmaterial have drawn increasing attention due to their strong photoluminescence (PL), good biocompatibility and low toxicity. Herein, we synthesize nontoxic fluorescent C-dots by hydrothermal treatment of the mixture of glucose and taurine, in which process the formation and the surface passivation of C-dots take place simultaneously. The influence of reaction temperature, reaction time and feed ratio of glucose to taurine on the PL property of C-dots is studied. As the C-dots exhibit sensitive pH and iron ion dependent PL property, they can be used for pH and Fe${}^{3+}$ sensing in solutions.

Carbon dots (CDs), as an emerging carbon material, have attracted considerable interest for their promising luminescent properties. However, the inevitable aggregation of CDs in solid-state results in some bottleneck problems such as aggregation-induced quenching and foster resonance energy transfer. Therefore, developing solid-sate CDs with good luminescent performance is still a challenge. Herein, a simple and low-cost approach is presented to prepare the solid-state CDs/SiO₂ composite in which the CDs were well dispersed and embedded in inorganic silica gel, hence restraining the natural issues of the solid-state CDs. As expected, the CDs/SiO₂ composite phosphors showed higher fluorescence intensity about twice than the CDs aqueous solution, and a high photoluminescence quantum yield of 21%. This work would be of significance for the preparation of CDs and even their practical applications.

A core–shell Co@C composite catalyst was prepared, characterized and used to activate peroxymonosulfate (PMS) for the degradation of paracetamol in water. Hybridized structures containing Co and graphitized carbon act as independent active sites for PMS activation initiating both radical and nonradical oxidation. A 91.57% paracetamol removal was reached in the Co@C/PMS system at 60 min. Radical quenching and electron paramagnetic resonance (EPR) tests show that nonradical ¹O₂ played predominant roles in the advanced oxidation process, while the other three radicals $\cdot {\mathrm{\text{O}}}_2^{-}$, •OH and ${\mathrm{\text{SO}}}_4^{•}$. also played a certain role in paracetamol degradation. After four cycles, the degradation could still reach 70%, which proves that the Co@C composite catalyst exhibits good stability.

A bimorph actuator of PVC-CFRP laminate (PVC: polyvinylchloride; CFRP: carbon fiber reinforced plastic) is fabricated, where its bending results from the large disparity between the coefficients of thermal expansion of PVC and CFRP. Thermal expansion is brought about by applying a voltage to the CFRP layer of the PVC-CFRP laminate to generate Joule heat. Thus, the PVC-CFRP laminate acts as an electroactive polymer actuator. The authors experimentally confirmed that laminate temperature due to Joule heat completely determines laminate deflection curvature, and also demonstrated that temperature determines the blocking force generated by PVC-CFRP laminate.

Wide-band absorption with low density is essential for microwave absorbers. We fabricated a novel micro-fibrous Fe/C nanocomposite with bulk density of only 0.47 ± 0.03 g cm^-3 using carbonized cotton fibers as template. Monodisperse iron nanoparticles with diameter of about 100 nm covered on the fibers and significantly increased the complex permittivity and permeability, and therefore enhanced the reflection loss (RL) for electromagnetic waves. The optimum thickness for the nanocomposite is 1.5–1.8 mm, with maximum RL of -14 dB and bandwidth of RL < -5 dB from 10 to 18 GHz, similar to that of Fe/C nanocomposite without using carbonized cotton fibers. Because of its low density and broad bandwidth at thin matching thickness, micro-fibrous Fe/C nanocomposite is a promising light-weight microwave absorber.

Catalysts are a key component of polymer electrolyte membrane fuel cells (PEMFCs). In this work, nitrogen-doped three-dimensional graphene-supported platinum (Pt-3DNG) catalysts are successfully prepared and characterized. SEM and TEM images show the Pt nanoparticles are uniformly dispersed in the sheets of nitrogen-doped 3DNG. Compared with that of the commercial Pt/C catalysts, Pt-3DNG show much better oxygen reduction reaction (ORR) activity and cycling stability, and the reduction in limit current density after 1000 cycles is only about 1.6% for the Pt-3DNG catalysts, whereas 7.2% for the commercial Pt/C catalysts. The single cell using Pt-3DNG catalysts in both the anode and the cathode show a higher peak power density (21.47mW cm${}^{-2})$ than that using commercial Pt/C catalysts (20.17mW cm${}^{-2})$ under the same conditions. These properties make this type of catalyst suitable for the application in PEMFCs.

Crystal structure and amorphous carbon of viscose-based activated carbon fiber (VACF) also have a close correlation with the formation of pore structure, thereafter dominating sorption capacities and mechanisms. In this paper, a novel phosphoric acid reactivation process assisted by sonication is proposed to modify VACF. Analysis results indicate that the application of sonication in phosphoric acid reactivation process can significantly improve the activation effect. After treating by the novel reactivation process, its micropore volume increased by 38.93%, mesopore volume increased by 676.56% and specific surface area increased by 53.45%. Moreover, the effect of the novel reactivation process on its crystal structure is to promote microcrystal growth and increase the disorder degree of crystal structure. Moreover, the simultaneous increase of micropore and mesopore is related to the decrease of amorphous carbon and the densifying of microcrystal structure.

The PEMFC (Polymer Exchange Membrane Fuel Cell) is one of the most researched generators in hydrogen technology. The PEMFCs offer low emissions, several applications in industry with high power density. The basic material for the construction of components in low-temperature fuel cells is carbon or its allotropic forms and carbon nanomaterials. Carbon materials are used to build diffusion layers of electrodes, as catalyst carriers, for the construction of covers/interconnectors and as fuel. In this work, the carbon materials used to build a single cell have been reviewed taking into account various methods of fabrication and modification of materials.

A novel visible-light flower-like CuS/graphene aerogels (CuS/GAs) photocatalyst has been synthesized via two-step solvothermal method. The CuS/GAs show outstanding synergies of adsorption and photocatalysis for anionic–cationic dyes degradation, which is attributed to unique network structure and excellent photoelectric properties of GAs. The high degradation ratio of Methyl orange and Methylene blue by synergy are 92% and 99.36%, which are about 4.1 and 3.2 times of that for pure CuS. The flower-like CuS/graphene aerogels resolve the low adsorption saturation problem of GAs and improve the photocatalytic performance of CuS, indicating CuS/GAs could be a promising photocatalyst for wastewater treatment.

The advancement of clean electrochemical technologies is highly related to the development of novel active materials. Especially, new carbon materials are playing great roles in the electrochemical energy storage and conversion devices. Herein, we discuss the recent progress on new carbon materials from several important aspects including new mold carbon sources, novel high-efficiency puffing method, tailored carbon arrays morphologies (vertical graphene and carbon nanotubes branch), and modified heteroatom (N and S)-doped carbon materials. Our perspective may shed a light on further study on new carbon materials for applications in energy storage and conversion.

Nitrogen-doped porous carbon (NPC) for high-performance supercapacitors has been synthesized from oily sludge waste by using KOH activation combined with in situ nitrogen doping method. The NPC possesses a hierarchical porous structure with high surface area of 2514.7m²g${}^{-1}$, large pore volume of 2.383cm³ g${}^{-1}$ and nitrogen content of 4.32%. The NPC-based electrode can deliver an outstanding capacitance of 414.2Fg${}^{-1}$ at 0.5Ag${}^{-1}$ and a good capacitance rate performance of 307.5Fg${}^{-1}$ (74.2% retention) at 50Ag${}^{-1}$. Moreover, the NPC exhibits an excellent cycling stability with little loss of capacitance after 5000 cycles at 5Ag${}^{-1}$.

Based on our observations made in our previous work that nitrogen (N)/oxygen (O) dual dopant porous hollow carbon nanocapsules (N/O-CNCs) have state-of-the-art lithium storage and sodium storage capabilities, we further studied their potassium storage performance in this study. It was found that for potassium storage, 259 mA h g${}^{-1}$ at 0.05 A g${}^{-1}$ can be retained up to 100 cycles, and 107 mA h g${}^{-1}$ at 1 A g${}^{-1}$ can be retained after 100 cycles. Even at 2 A g${}^{-1}$, an excellent rate capability of 73.4 mA h g${}^{-1}$ in K-ion batteries (KIBs) was delivered. A capacitive charge–storage mechanism dominated the potassium storage of N/O-CNCs at high rates during the potassiation/depotassiation process through kinetics analysis, ensuring a remarkable rate performance.

Nanoflower-like hollow carbon sphere (CS) materials with two different heteroatoms doping (N, P) were prepared by a simple synthetic method (NPCS). The specific surface area of NPCS can reach a high value of 396 m²/g. The NPCS has a high degree of hollowness and the self-assembled nanosheet of NPCS forms a fast electron transport channel, and also increases active area in contact with electrolyte. The doping of heteroatoms increases the defect level of the carbon-based nanomaterials and changes the local electron state of the material, thus forming storage sites on the surface of the material, which can be used as a station for ions collecting and distributing. The material was studied as an active material for supercapacitors, and the specific capacitance reached 274.9 F/g. After the 4000th cycle stability test, it still maintained 95.2% of the specific capacitance, indicating that the material has excellent properties of supercapacitor materials.

Carbon-based nanomaterials (NMs) are a specific class of materials used in biomedical applications, such as the delivery of therapeutics, biomedical imaging, biosensors, tissue engineering, and genetic engineering. Carbon-based NMs are interesting tools with specific qualities, including strong mechanical structure, good conductivity, appealing visual qualities and great chemical versatility. Among these carbon-based NMs, graphene and carbon nanotubes (CNTs) are of great biological importance. In this paper, we discuss about graphene, CNTs, fullerene and carbon quantum dots (CQDs), the structure, properties, toxicity, mechanism of action and applications in cancer treatment and diagnosis. Graphene, fullerene, CNTs and CQDs are allotropic forms of carbon. The circle of biomedical engineering is increasing daily, and in recent years, carbon-based NMs have played a vital role as biomaterials. Carbon-based NMs attracted the attention of a wide range of researchers due to their multifunctional properties. In this paper, we discuss the function of carbon-based NMs in the detection and treatment of cancer and explore their role in controlling tumor-causing cells and damaging cancer-causing cells. If we use their derivatives as a source for cancer treatment and diagnosis, we can cease tumor growth to a tremendous level.

Carbon onions (CNOs) are highly desirable in the field of electromagnetic wave absorption (EMWA) due to their onion-like structure, low density and excellent conductivity. Herein nickel encapsulated CNOs were fabricated by arc discharge and then transformed into hollow ones via annealing at 900^∘C. The structure and EMWA performance of the hollow and nickel encapsulated CNOs were analyzed in detail to investigate the relationship of their EMWA properties and structure. The better EMWA properties of nickel encapsulated CNOs showed that the core–shell interface contributed more EMMA in comparison to the onion-like configuration.