For a material to be used as energy, understanding its combustion behavior is crucial. Biomass is one such material that is increasingly gaining traction. Biomass may be utilized by direct combustion or transformation into fluid or solid biomass-based fuels. In this work, slow pyrolysis of groundnut shells, bagasse, rice husks and coffee husks was done to produce briquettes with cassava starch binder. Thermogravimetric analysis (TGA) was carried out using an Eltra Thermostep thermogravimetric analyzer. The samples were heated from ambient to 920 deg. Celsius. This analysis provided combustion explanations in terms of the weight loss, burning rates, peak temperatures, char residues and mean reactivity. TGA results showed that binder inclusion reduced the amount of fixed carbon present in the developed briquettes, thus slightly reducing their calorific values. Rice husks briquettes yielded the least weight loss (20.9% and 24.7% for 30g and 50g binder incorporations respectively) compared to others, owing to former’s higher ash contents. Increase in binder contents reduced the amount of char residues, caused by reducing ash contents in the developed briquettes. Peak temperatures and char residues generally increased with increasing binder content. This signifies increasing thermal stabilities of the developed briquettes. Highest char residues were obtained by briquettes developed with rice husks at 30g binder while briquettes developed with bagasse briquettes developed at 50g binder had the least char residues. The highest mean reactivities were obtained in briquettes developed from bagasse and coffee husks while briquettes developed from rice husks had lowest mean reactivities. Briquettes developed in this study showed sufficient combustion properties suitable to provide energy for domestic and industrial applications.

A scalable preparation of in situ N-doped disordered carbon nanosheets from reduced melamine formaldehyde resin is demonstrated. For the first time, nanosheets prepared by such a process have been tested as anodes for lithium ion and sodium ion batteries. Li-ion battery half-cell delivers a reversible capacity of about 500 mA h/g at a specific current of 100 mA/g, and also a capacity of 250 mA h/g at a specific current of 500 mA/g is retained after 600 cycles. For Na-ion batteries, a reasonable capacity of about 150 mA h/g is recorded at a specific current of 50 mA/g, and a capacity of 120 mA h/g at a specific current of 250 mA/g is retained after 350 cycles. The sloppy low-voltage profile obtained for both the lithium ion and sodium ion cells corresponds to the nanosheet anodes, being soft carbon-like, thereby demonstrating superior cycling stability and safety by avoiding metal plating and dendrite formation.

Simple glucose solutions were heat treated in an attempt to produce carbon nanodots (CNDTs) with a monodisperse size distribution using a bottom-up approach. Absorption and fluorescence properties of the heat-treated solutions display remarkable similarity to CNDTs reported in the literature. However, particle-sizing and AFM measurements indicate the increasing fluorescence is accompanied by the growth of particles that are larger than most CNDTs discussed in the literature (a concentrated population of monodisperse 30 nm particles and a low concentration of much larger, roughly 500 nm, particles). A dialysis study, shows these larger particles are not responsible for the bulk of the optical properties but, rather the optical properties likely stem from molecular by-products that accompany the heating and caramelization of the sugar.

Herein, we report N, S co-doped carbon dots (NS CDs) as stabilizing and reducing agents for the synthesis of N, S doped carbon dots-Au nanocomposites (NS CDs-Au NCs) through the solution method and explore the catalytic property of the synthesized nanocomposites in the reduction of nitro aromatic compounds (NACs) such as 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), and nitrobenzene (NB). The appraisal of the catalytic efficacy of the NS CDs-Au NCs was premised on real time monitoring of the reduction of NACs using UV-Visible absorption spectroscopy. The apparent rate constants (kapp) of reduction were found to follow the pseudo-first-order kinetics having values of 1.37 × 10−1, 8.9 × 10−2, and 5.35 × 10−2 s−1 for 4-NP, 4-NA, and NB, respectively. The apparent rate constant (1.37 × 10−1 s−1) observed for the reduction of 4-NP by NaBH4 using NS CDs-Au NCs has been found to be one of the highest values reported in the literature so far thereby validating their excellent efficacy as a catalyst.

Green culms of bamboo and charcoal of Bambusa multiplex were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) mapping. A dynamic observation of the initial stage of carbonization was also performed in-situ by heating a radial longitudinal section of the bamboo culm at a rate of 20°C/min up to 500°C. EDS mapping of the green bamboo culms detected Si signals in the harder cells such as the epidermis (Ep), cortex (Cor) and vascular bundle sheath (Bs) and between these cells as silicon oxide particles. Appreciable morphological change of the cells occurred in a temperature range of about 300–400°C due to the decomposition of cellulose that is the main component of the bamboo cells. The charcoal of the bamboo culm has a skin layer which originates from the Ep and Cor and the main central cylinder with many openings that originate from the expanded xylem and phloem holes. During carbonization, the Si atoms in the Ep and Cor were segregated as thin silicon oxide layers onto both the sides of the skin layer and the Si included in the Bs fibers and parenchyma cells accumulated near the walls of the openings.

Lignin-based phenol formaldehyde resin was synthesized using phenolated calcium lignosulfonate, and porous carbon with good wettability was prepared after carbonization and potassium hydroxide (KOH) activation. The results indicated that when the KOH to the carbonized sample mass ratio was 6:1, the prepared carbon had a rich porous structure and higher surface area, with a specific surface area of 1320.13 m2/g. Furthermore, the porous carbon exhibited a maximum specific capacitance of 204.88 F/g at a current density of 0.5 A/g in the potential range −1.0 to 0 V in a 6 M KOH solution and a low equivalent series resistance of 0.64 Ω. The phenolated calcium lignosulfonate-based phenol formaldehyde resin porous carbon demonstrated a favorable electric double-layer performance.

Porous carbon derived from biomass materials with enrich, low cost, clean, and renewable merits, exhibits various physical and chemical properties. So, it is of great significance to rationally utilize biomass materials for producing porous carbon with low cost to reduce overusing fossil fuel and environmental pollution. In this report, porous carbon has been fabricated using fruits shells of the Paulownia tomentosa by a facile method of KOH-activation. The as-obtained porous carbon containing a larger number of micropores and slight mesopores possesses a high specific surface area (1914.4 m2/g) and well hierarchical porosity. As the anode for sodium ion batteries, the porous carbon sample displays superior cycling stability and rate capability, delivering a reversible specific capacity of 179 mA h/g at 50 mA/g after 100 cycles and a discharge specific capacity of 100 mA h/g at 1 A/g.

Much of the global agricultural by products go waste, especially in developing nations where much of their revenues depend on the exports of raw agricultural products. Such waste streams, if converted to “value added” products could serve as additional source of revenue while simultaneously having a positive impact on the socio-economic well being of the people. We present a preliminary investigation on utilizing chemical activation technique and ball milling to convert agricultural waste streams such as cocoa pod, coconut husk, palm midrib and calabash commonly found in Ghana into ultra-high surface area activated carbon. Such activated carbons are suitable for myriads of applications in environmental remediation, climate management, energy storage and conversion systems (batteries and supercapacitors), and improving crop productivity. We achieved BET surface area as high as ∼ 3000 m2/g.

The formation mechanism and chemical form of insoluble C-14 found in PWR need to be examined in order to predict its environmental behavior after disposal. This study investigates the alteration of ion-exchange resin by heating and irradiation, because past studies indicated the ion-exchange resin may be the origin of insoluble C-14.

Resin was heated at 300 °C in solution with low oxygen content to simulate the environment of PWR coolant. The sulfo group was found to detach within 8 h, and structures similar to polystyrene were remained. This is followed by detachment of H from the alkyl group, condensation reaction, and the formation of amorphous carbon-like structure. After heating for 24 and 96 h, the resin was irradiated by 60Co γ-rays in the solution. The FT-IR and TG measurements after irradiation suggested that OH and COOH groups were formed on the surface of the resin. These functional groups may be involved in reactions that finally form the amorphous carbon.

In addition, the characteristics of heated and irradiated resin were compared to real insoluble-C (CRUD) sample in PWR (in Appendix).

A novel synthesis of Al (1xxx)/carbonised coconut shell (CCS) nanoparticles using a ball milling technique was investigated. Initial Al/0.1%CCS powders of an average size of 51.06μm was milled for a period of 70 h. The milled particles at 16, 46 and 70 h were characterized using X-ray diffractomer (XRD), scanning electron microscope (SEM), transmission electron microscope and UV-Vis spectrophotometer. Result revealed that the calculated particle crystallite size from XRD aided with Scherrer’s equation is consistent with particle image sizes obtained from SEM aided with software. TEM image depicted variation in orientation and appearance of the Al 1xxx/0.1% CCS nanoparticles at different milling time. The wide variation in the particle size is attributable to different ball impacts on the individual powders during the ball milling process. Increased maximum absorbance observed with the milled particles when compared with the initial powders is an indication of quantum/nanosizing effect due to ball milling.

A hierarchical porous carbon with bimodal pore size distribution was synthesized using pyrolysis and controlled activation of polymer gel derived from furfuryl alcohol and phloroglucinol using a soft templating approach. Symmetric capacitors made using the synthesized carbon electrodes in neat 1-butyl 3-methylimidazolium tetrafluoroborate showed a specific capacitance of 141 F/g at 1 A/g when cycled between 0 and 3.8 V at room temperature. The capacitor also showed 90% capacitance retention over 5000 cycles. Equivalent circuit modeling of impedance spectra was done to monitor changes and provide microstructural details during cycling and temperature studies. Cyclic voltammetry showed the presence of specific adsorption of the electrolyte ions on the carbon electrode and this was in good agreement with strong dependence of specific capacitance on temperature. Such strong interaction along with the nature of electrical double layer formed in the hierarchical porous carbon results in widening the voltage stability window of the capacitor.

Heteroatom-doped carbon materials have attracted immense interest as advanced supercapacitor electrode materials due to their unique properties. A carbon cloth-supported, nitrogen-doped carbon “spider web” network full of macropores and mesopores is developed via the pyrolysis of polyaniline nanofibers in ammonia atmosphere. The presence of mesopores and macropores can provide ion-buffering reservoirs to shorten the ion diffusion distance to the interior part of the carbon network. Carbonization in ammonia introduced N heteroatoms through gas phase chemical reactions between ammonia and the oxygen functionalities on the carbon surface. The enhanced ion-accessible surface area and improved charge transfer rate can be achieved. The N-doped carbon “spider web” exhibited a high specific capacitance of 266 F/g at a scan rate of 2 mV/s. Even when the scan rate was increased to 500 mV/s, 61% of its capacitance could still be retained, evidencing its excellent rate performance. The demonstrated strategy is anticipated to be generally effective for preparing heteroatom-doped carbon electrodes with other polymers.

Replacing precious and nondurable platinum-based catalysts by economical and commercially available materials is a key issue addressed in contemporary fuel cell technology. Carbon-based nanomaterials display great potential to improve fuel tolerance and reduce the cost and stress on metal scalability. However, their relatively low catalytic activity limits the development and application of these catalysts. In this study, we have synthesized a nitrogen-doped carbon electrocatalyst from metal–organic frameworks and carbon nanotube composites, taking advantage of the existing N in the organic linker in the MOFs with more N added through ammonia treatment. The morphology and composition of synthesized catalysts were characterized by SEM, TEM, XPS, and Raman. The derived catalyst exhibited superior catalytic activity than that of commercial Pt-based catalysts. The N enriched carbon catalyst with high surface area, a graphitic carbon skeleton, and a hierarchical porous structure facilitated the mass and charge transfer during electrolysis.

Because of its unique properties and promising applications, graphene has attracted great interest from both academia and industry in the last decade. For studies on graphene as well as for applications, it is essential to develop techniques to prepare graphene in a controllable way. Graphene can be produced in the form of nano-/microflakes using a top-down method by the exfoliation of graphite or the reduction of graphene oxide, or in the form of a film or foam in a bottom-up method, predominantly by chemical vapor deposition of carbon precursors on catalytic substrates. This article focuses on the catalytic substrates, especially metals, used for graphene growth. We also discuss graphene growth mechanisms and kinetics, control of the number of graphene layers and their stacking order, engineering of large-area graphene single crystals, as well as low-temperature growth.

In this work, the hybrid carbon nanofibers (Cu2O/CNFs) containing cuprous oxide (Cu2O) nanoparticles were prepared by a convenient electrospinning method and following a carbonization treatment. The morphology, composition, and microstructure of the Cu2O/CNFs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometer. The as-prepared Cu2O/CNFs exhibited a stronger absorption in the range of 250–700 nm. The band gap energy of the Cu2O/CNFs was estimated to be 2.0 eV. Due to the synergistic effect between photocatalytic activity of Cu2O and excellent adsorption capacity of CNFs, the obtained Cu2O/CNFs exhibited excellent photocatalytic activity for degradation of rhodamine B (RhB) and phenol. The possible mechanism for degradation of RhB and phenol degradation were also discussed. The resultant hybrid carbon composites offer the significant advantages, such as low dosage, high catalytic activity, easy recycling, and excellent stability. We hope that the resultant hybrid composite Cu2O/CNFs could be applied as catalytic materials for further application in the future.

This work designed a facile preparation for an SiO2/C composite as the anode material for lithium ion battery. Both SiO2 and carbon are amorphous. SiO2 and carbon are mixed uniformly. The SiO2/C composite shows high specific capacity, cycle stability, and rate capability in lithium ion battery charge–discharge test. A stable reversible capacity of 1024 mA h/g at the current density of 100 mA/g is reached. The capacity retains 83% after 100 cycles. The uniform mixture of SiO2 and carbon leads to reduced volume change during the lithiation and delithiation of SiO2, together with the amorphous nature of SiO2 explains the high cycling stability. The carbon coating is a key factor for the high capacity and stability due to the increased electrical conductivity and reduced volume change. The resistance of the solid electrolyte interface film and charge transfer resistance of the SiO2/C composite are much smaller than those of pure carbon, which is a direct proof of the improved conductivity of the material by the carbon coating.

Typically, composites are lightweight, and high strength and hence are attractive for use in aerospace, automotive applications. For most of the aerospace applications, laminated composites serve as a primary load carrying structure and are subjected to a variety of loadings including transverse impact and fatigue loadings. The typical laminated composites are weak in the transverse direction. Since laminated composites are weak in the transverse direction, when these laminates are subjected to transverse loading, most of the time interlaminar failure occurs in the form of delaminations. Conventional methods of preventing delaminations include improving the design and improving the matrix properties. Although, improving the composite design suppress delaminations to some extent, a substantial amount of compromise with other properties like increase of resin volume fraction, degradation of inplane properties, voids, distortion in fibers and laminate, an increase of cost or process complexities are common. The present day researchers are more focused on improving matrix by nanomaterials such as Carbon Nano Tube(CNT), though the cost is hampering its potential for an industrial prospect. Electrospun nanofibers are being considered as a cheap alternative for vapor grown CNTs and other nanomaterials which involve complex fabrication and application methods in the field of interlaminar reinforcement for polymer matrix composites. Most of the aerospace quality composites are manufactured using prepreg due to the higher percentage of fiber volume fraction and hence higher mechanical properties. Although, nanomaterials have been recognized as a major advancement for improvement of composite material properties, there has been very little effort to fabricate prepregs using nanofibers. The current research focuses on the challenges involved in the fabrication of nanofiber enhanced prepregs and process difficulties and possible solutions for fabricating electrospun nanofiber overlaid prepregs. The effects of heat treatment on electrospun nanofiber overlaid woven fabric on the mechanical properties of both glass and carbon are investigated. A novel technique is proposed for manufacturing of nanofiber engineered prepregs.

Peptide nanotubes based on short dipeptide diphenylalanine (FF) attract a lot of attention due to their unique physical properties ranging from strong piezoelectricity to extraordinary mechanical rigidity. In this work, we present the results of high-resolution Piezoresponse Force Microscopy (PFM) measurements in FF microtubes prepared from the solution. First in-situ temperature measurements show that the effective shear piezoelectric coefficient d15 (proportional to axial polarization) significantly decreases (to about half of the initial value) under heating up to 100 oC. The piezoresponse becomes inhomogeneous over the surface being higher in the center of the tubes. Further, PFM study of a composite consisting of FF microtubes and reduced graphene oxide (rGO) was performed. We show that piezoelectric properties of peptide microtubes are significantly modified and radial (vertical) piezoresponse appears in the presence of rGO as confirmed via PFM analysis. The results are rationalized in terms of molecular approach in which π – π molecular interaction between rGO and dipeptide is responsible for the appearance of radial component of polarization in such hybrid structures.

In this paper many studies have been carried out to ascertain the phenomenon of strain-induced precipitation and coarsening of carbides in AISI H13 hot-work die steel during the tests at 700 °C. The microstructure of H13 with various loadings was studied to identify the effects of mechanical strain on the evolutionary behavior of carbides. SEM and TEM were used to observe the size and distribution of the carbides of each sample. It was found that the coagulation of carbides is more obvious in mechanical strained samples than that in mechanical strain-free sample which means mechanical strain promotes the precipitation and coarsening of carbides, and these processes are affected by the mechanical strain amplitude. Precipitation is increased by the strain enhanced because of more nucleation sites produced and accelerate the diffusion of solute atoms. Moreover, the results are shown that lower strain rates are more beneficial for precipitation and coarsening of carbides under the same strain because they provide a longer time to nucleate and grow into nuclei.

There has been a continuous call for active, durable, and low-cost catalysts for a range of catalysis reactions. In this paper, porous Co@C composed of uniformly dispersed Co metal nanoparticles in hexagonal-shaped prisms carbon matrix were fabricated by in situ pyrolysis of hexagonal-shaped prismatic Co-MOF-74 crystals. The obtained nanoporous carbons have a high surface area of 195.2 m2/g and a strong magnetic response, thereby realizing fast molecular diffusion of reactant and easy magnetic separation. The resulting Co@C catalyst show a superior and durable catalytic activity for reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Moreover, Co@C can be recycled and still retains more than 75% of its original catalytic activity after 6 cycles. Therefore, it is reasonable to believe that such Co@C nanocomposites have great potential as a highly efficient and low-cost heterogeneous catalyst. It is believed that MOFs can be used to produce other catalysts with high porosity and uniformly dispersed active sites.