Preparation Of Nanoporous Carbons Research Articles

Preparation of Nanoporous Carbon from Rice Husk with Improved Textural Characteristics for Hydrogen Sorption

This study proposes a method to control the pore-forming process by performing preliminary mechanical activation of the initial rice husk before carbonization. Preliminary mechanical activation of the initial rice husk leads to the loosening of the intercellular substance and its partial depolymerization, thereby increasing the availability of its internal structure for pore formation during carbonization and chemical activation. Using the method described above, nanoporous carbon was obtained with a Brunauer–Emmett–Teller (BET)-calculated specific surface area of 2713 m2/g, a micropore specific surface area calculated by using the Dubinina–Radushkevich (D-R) method of 3099 m2/g, and a total pore volume calculated by using the Barett–Joyner–Halenda (BJH) method of 1.625 cm3/g. Due to these characteristics, the adsorption capacity in the obtained sample was for hydrogen 3.7 wt.% at a temperature of −190 °C and a pressure of 9 kgf/cm2, which is 29.7% higher than the adsorption capacity of nanoporous carbon obtained based on rice husk without mechanical activation. The composite “carbon–platinum” NC-2/Pt10%, at a temperature of 20 °C and a pressure of 9 kgf/cm2, showed an increase in sorption capacity of 27% compared to pure nanoporous carbon NC-2, which is explained by the emergence of the spillover effect.

Preparation of Nanoporous Carbon from a Spherical NbC/C Nanocomposite and Its Properties

Preparation of Nanoporous Carbon from a Spherical NbC/C Nanocomposite and Its Properties

Preparation of Nanoporous Carbon from Rice Husk through Alkali Activation Treatment: a Detailed Mechanistic Investigation

Preparation of Nanoporous Carbon from Rice Husk through Alkali Activation Treatment: a Detailed Mechanistic Investigation

A green and fast approach to nanoporous carbons with tuned porosity: UV-assisted condensation of organic compounds at room temperature

This work reports a green and fast approach to the synthesis of nanoporous carbon materials based on the UV-assisted condensation of organic compounds as precursors. This new approach offers several improvements over the classical soft template and sol-gel routes for the synthesis of materials: versatility of organic precursors, shorter synthesis time, and ambient conditions. Owing to the specificity of the UV-assisted reactions mechanisms, organic compounds of varied chemical composition can be used as precursors in the preparation of nanoporous carbons with tuned porous features. The method consisted in the exposure of an aqueous solution of the organic precursors to UV light for 60 min at room temperature in the absence of a catalyst, allowing an outstanding shortening of the synthesis time compared to sol-gel routes. Furthermore, UV irradiation promoted the cross-linking of the polymer chains of precursors at room temperature, as opposed to classical methods that require an additional step at mild/high temperatures. By changing the chemistry of the organic compound used as precursor, it was possible to modulate the surface area (from 10 to 720 m2 g−1) and the porosity of the synthesized carbons within the micro-/mesopore range. The obtained carbons also presented varied morphology depending on the precursor, from dense aggregates to ordered hexagonal arrangements of nanometric dimensions.

Fe/Nanoporous Carbon Catalysts Obtained from Molasses for the Limonene Oxidation Process

Iron/nanoporous carbon catalysts (Fe/NPC) were used in the studies on limonene oxidation employing methanol as a solvent and aqueous hydrogen peroxide as an oxidizing agent. The nanoporous carbon support of the catalyst was produced from molasses, a sugar refinery waste product. To the best of our knowledge, there are no reports on the preparation of nanoporous carbon from molasses. The content of iron in the Fe/NPC catalysts studied included 0.68, 1.32 and 2.64 wt% Fe. The products of the limonene oxidation process were 1,2-epoxylimonene and its diol, carveol and perillyl alcohol, which are compounds with a large number of applications. The conversion of limonene reached 60 mol%. The “pure” NPC material was also active in the oxidation process. The utilized catalytic system is simple and cheap, and the use of environmentally-friendly H2O2 and the natural product limonene signify that this process can be considered as a “green process”. The results of the current research indicate that the utilization of molasses for the preparation of the carbonaceous catalysts active in the limonene oxidation is feasible, and these catalysts could be used in numerous industrial oxidation processes.Graphical

Elimination of anionic dye by using nanoporous carbon prepared from an industrial biowaste

The preparation of nanoporous carbon from tomato waste (TWNC), and its ability to remove Orange II (OII) dye were reported. The TWNC was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Brunauer Teller surface area (BET), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The effects of initial concentration, solution pH, adsorbent dosage and temperature were investigated. The kinetic data followed a pseudo-first order model. The mechanism of the process was determined from the intraparticle diffusion model. The isotherm analysis indicated that the adsorption data could be represented by the Langmuir model. The maximum monolayer adsorption capacity was determined as 312.5mgg−1 under determined optimum conditions of variables (pH2.0, adsorbent dosage 0.1gL−1, contact time 180min and temperature 50°C). Thermodynamic study showed that the adsorption was spontaneous and endothermic. The results indicate that TWNC can be employed as low-cost alternative to expensive commercial activated carbon for treatment of industrial wastewater containing OII.

Preparation of nanoporous carbons with hierarchical pore structure for CO2 capture

Preparation of nanoporous carbons with hierarchical pore structure for CO2 capture

Preparation of nanoporous carbons with hierarchical pore structure for CO2 capture

Nanoporous carbons with a hierarchical pore structure were prepared by a combination of hard-templating of a thermosetting phenolic resin containing silica nanoparticles, pyrolysis and KOH activation. The influence of the amount of KOH on the pore structure of the templated and activated carbons was investigated by N2 adsorption and the effect of pore structure on the CO2 adsorption capacity was investigated by thermogravimetric analysis. Results indicated that KOH activation promoted the formation of micropores and small mesopores for the templated carbon. The utilization ratio of mesopores for the capture of CO2 is high compared with that of micropores. The porous carbon prepared under a mass ratio of KOH to templated carbon of 2:1 has both developed mesopores and micropores, and has a largest adsorption capacity for CO2 among all samples investigated.

Fabrication and Electrocatalytic Application of Nanoporous Carbon Material with Different Pore Diameters

Here we report on the preparation of nanoporous carbons with different pore diameters loaded with different amounts of platinum and their application as anodic electrodes for the polymer electrolyte membrane fuel cells (PEMFCs). The materials were characterized by nitrogen adsorption, XRD and HRTEM. The role of the amount of the platinum and the pore diameter of the nanoporous carbon supports on the anodic performance in the PEMFC has been investigated. It has been found that the anodic activity of the platinum supported nanoporous carbon materials significantly increases with increasing the amount of platinum on the surface of the supports. Interestingly, nanoporous carbon material with a larger pore diameter shows excellent performance as an anodic electrode support. The electrode activity of the platinum loaded nanoporous carbon was also compared with that of the commercially available carbon black support for the PEMFCs. Nanoporous carbon supports are found to be the best, showing much higher performance as compared to that of carbon black.

Preparation of nanoporous carbons by defluorination

Preparation of nanoporous carbons by defluorination

Preparation of nanoporous carbons by defluorination

Preparation of nanoporous carbons by defluorination

Preparation of nanoporous carbons from graphite nanofibres

In this study we manufactured highly porous graphite nanofibres (GNFs) byphysical activation in order to develop promising energy storage materials.The activation was performed at activation temperatures in the range of800–1050 °C. The pore structures of the porous GNFs were analysed usingN2/77 K adsorption isotherms. After the activation, the porous GNFs showed a decrease in diameterand scratches on their surfaces, resulting from surface oxidation and the opening of the graphiticlayers, respectively. It was found that the specific surface area of the porous GNFs prepared at1050 °C was morethan 2000 m2 g−1 without loss of their fibre shape or serious increase in electrical resistivity. Thisresult indicates that porous GNFs prepared under optimal conditions can have amuch higher specific surface area and are promising materials for energy storagetechnologies.