High Surface Area Mesoporous Carbon Research Articles

High surface area mesoporous carbon from black cumin (Nigella sativa) processing industry solid residues via single-stage K2CO3 assisted carbonization method: Production optimization, characterization and its some water pollutants removal and supercapacitor performance

In this study, solid residues (BR) from the black cumin (Nigella sativa) processing industry, an abundant and sustainable raw material, were converted into high surface area mesoporous activated carbon (AC) under optimum production conditions using a single-stage K2CO3 assisted carbonization method. The optimal AC (BRAC) which had the highest BET surface area (2211 m2/g), total pore volume (1.262 cm3/g), and mean pore diameter (2.8 nm) was achieved in the conditions of a K2CO3 impregnation ratio of 1:1, a carbonization temperature of 900 °C, and a carbonization period of 1 h. To test its adsorption performance from the aqueous phase, methylene blue dye, oxytetracycline antibiotic, and lead metal ions were selected as model water pollutants and found to be 714.3, 833.3, and 500.0 mg/g, respectively, at 25 °C Also, the electrode made of BRAC showed electrochemical capacitor performance with a high gravimetric capacitance (210 F/g) and cyclic stability (95 %).

The Use of High Surface Area Mesoporous-Activated Carbon from Longan Seed Biomass for Increasing Capacity and Kinetics of Methylene Blue Adsorption from Aqueous Solution.

Microporous- and mesoporous-activated carbons were produced from longan seed biomass through physical activation with CO2 under the same activation conditions of time and temperature. The specially prepared mesoporous carbon showed the maximum porous properties with the specific surface area of 1773 m2/g and mesopore volume of 0.474 cm3/g which accounts for 44.1% of the total pore volume. These activated carbons were utilized as porous adsorbents for the removal of methylene blue (MB) from an aqueous solution and their effectiveness was evaluated for both the adsorption kinetics and capacity. The adsorption kinetic data of MB were analyzed by the pseudo-first-order model, the pseudo-second-order model, and the pore-diffusion model equations. It was found that the adsorption kinetic behavior for all carbons tested was best described by the pseudo-second-order model. The effective pore diffusivity (De) derived from the pore-diffusion model had the values of 4.657 × 10−7–6.014 × 10−7 cm2/s and 4.668 × 10−7–19.920 × 10−7 cm2/s for the microporous- and mesoporous-activated carbons, respectively. Three well-known adsorption models, namely the Langmuir, Freundlich and Redlich–Peterson equations were tested with the experimental MB adsorption isotherms, and the results showed that the Redlich–Peterson model provided the overall best fitting of the isotherm data. In addition, the maximum capacity for MB adsorption of 1000 mg/g was achieved with the mesoporous carbon having the largest surface area and pore volume. The initial pH of MB solution had virtually no effect on the adsorption capacity and removal efficiency of the methylene blue dye. Increasing temperature over the range from 35 to 55 °C increased the adsorption of methylene blue, presumably caused by the increase in the diffusion rate of methylene blue to the adsorption sites that could promote the interaction frequency between the adsorbent surface and the adsorbate molecules. Overall, the high surface area mesoporous carbon was superior to the microporous carbon in view of the adsorption kinetics and capacity, when both carbons were used for the removal of MB from an aqueous solution.

A Simple Method for the Synthesis of High Surface Area Mesoporous Carbon Monolith via Soft Template Technique

The aim of this work was the synthesis and characterization of a mesoporous carbon monolith (MC). The MC was prepared using the soft template method. Resorcinol and formaldehyde were used as the carbon precursor and triblock copolymer Pluronic F127 as the templating agent under acidic conditions. Several techniques were used to characterize the synthesized material such as Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller nitrogen sorption measurements (BET), Powder X-Ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), and Thermogravimetric Analysis (TGA). The work characterized the changes due to the decomposition of the template during the carbonization process to form the pores in the carbon material. The result confirmed that the mesoporous monolithic carbon prepared had a high surface area and a narrow pore size in the mesometer range.

Ionic Liquids at the Electrode Interface: Insights into Surface Passivation and Framework Expansion of Hard Carbon Anodes

Ionic liquids are being extensively explored as an alternative to carbonate-based electrolytes in reversible batteries, as they can exhibit lower flammability and volatility, and better overall safety. The polarity and acidity/basicity of ionic liquids can be tuned to control solubility, and can influence the electrochemical window and interfacial properties when used in batteries. In this study, 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl) imide (EMIM.TFSI) and 1-methyl-1-propypyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY.TFSI) were selected because they are well-known, relatively stable ionic liquids with large electrochemical windows which show strikingly different behavior with carbonaceous anodes due to differences in interface passivation. High surface area mesoporous hard carbon anodes were employed to provide a large signal from the interfacial chemistry of these electrolytes during reversible cycling. A combination of operando small-angle neutron scattering (SANS) and ex-situ electrochemical studies were used to understand the differences in solid electrolyte interphase (SEI) for these ionic liquids, and the relationship of SEI formation to hard carbon microstructural changes. Reversible hard carbon expansion is observed in the first cycle for the electrolyte lithium bis(trifluoro-methanesulfonyl)imide (LiTFSI)/EMIM.TFSI related to EMIM+ intercalation and deintercalation before a stable SEI is formed, while a largely irreversible framework expansion of 15% is observed for the LiTFSI/MPPY.TFSI electrolyte. There is only relatively minor expansion and contraction in subsequent cycles after a suitable solid electrolyte interphase (SEI) has formed. Irreversible framework expansion in conjunction with SEI formation is found to be essential for the stable cycling of hard carbon electrodes.[1]Acknowledgement: Research was sponsored by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. Research at Spallation Neutron Source user facility was sponsored by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC.[1] Bridges, C.A.; Sun, X.G.; Guo, B.K.; Heller, W.T.; He, L.L.; Paranthaman, M.P.; Dai, S. “Observing Framework Expansion of Ordered Mesoporous Hard Carbon Anodes with Ionic Liquid Electrolytes via in Situ Small-Angle Neutron Scattering.” ACS Energy Lett. 2017, 2, (7), 1698-1704.

Templated N-Doped and O-Doped Carbons for Energy Storage and Conversion

Global energy demand has significantly increased in the last decades, and consequently, the environmental problems associated with the use of fossil fuels. More sustainable energy sources are required, and it is imperative to develop more efficient energy storage and conversion devices. In this context, batteries and fuel cells are promising options for stationary, portable, and transport applications.[1] Unfortunately, both polymer electrolyte membrane fuel cells (PEMFCs) and metal-air batteries are limited by the need for high Pt loadings in the cathode due to kinetic limitations imposed by the sluggish oxygen reduction reaction (ORR).[2] The conditions in the cathode can also result in the degradation of the carbon support (carbon corrosion) and Pt agglomeration, dislodgement, and dissolution.[3] Efforts aimed to solve these problems have intensified, principally the search for new catalysts materials to reduce or eliminate the need for Pt.[4] In the framework of these initiatives, heteroatoms-doped carbons obtained by carbonization of organic polymer gels (OPGs) are seen as attractive candidates for achieving some of these goals.[5] Even though resorcinol-formaldehyde polymers have been the most extensively studied, other precursors have been recently investigated for applications in batteries and supercapacitors.[6] In this study, high surface area mesoporous carbon materials with variable N and O contents were produced by carbonization of melamine-formaldehyde (MF) and resorcinol-formaldehyde (RF) polymer gels in the presence of SiO2 nanoparticles (20 to 200 nm) as hard-templates. Carbon products with up to 8 N-atom% and surface areas up to 500 m2/g were obtained by carbonization of nitrogen-rich melamine polymers (MF-C) depending on the annealing conditions (950°C or 1500°C). By adopting a similar approach, carbons with variable oxygen and nitrogen content were prepared by the combustion of resorcinol-formaldehyde (RF-C) and resorcinol-melamine-formaldehyde (RMF-C) polymers. The materials structure and chemical composition have been extensively investigated using a plethora of different techniques.Pt/MF-C and Pt/RF-C samples were prepared by an impregnation method to evaluate the stability of these catalysts under oxidizing and acidic conditions, as well as their catalytic activity toward the ORR. It was found that an increase in annealing temperature from 950 to 1500 oC resulted in a significant improvement in stability upon cycling the potential in accelerated ageing tests in acid media (0 to 1.4 V vs NHE) comparable or even better than the benchmark material Pt/Vulcan, and a preferential 4-electron reduction pathway for the ORR, as required for fuel cells and metal-air batteries applications. Preliminary data for the reduction of oxygen on Fe/MF-C and Fe/RF-C samples are underway, and preliminary results will also be presented.

Enhancing stability and efficiency of oxygen reduction reaction in polymer electrolyte fuel cells with high surface area mesoporous carbon synthesized from spent mushroom compost

Activated mesoporous carbon obtained from spent mushroom compost as a catalyst support provides enhanced long-term durability during the oxygen reduction reaction.

Direct growth of mesoporous Carbon on aluminum foil for supercapacitors devices

Nowadays it is mandatory sustainable energy production and storage. In this scenario, supercapacitors play an important role as ultrafast energy storage devices with long lifetime and high efficiency features. The new era of these devices is based on new materials and electrolytes that are environment-friendly during manufacturing and applications. This paper presents a high surface area mesoporous Carbon (MC) material direct growth on aluminum current collector on an environment-friendly process. MC material showed specific capacitance of ~ 8 F g− 1 and impressive chemical stability. Prepared with two MC electrodes, low-cost cellulosic separator and aqueous neutral electrolyte, the supercapacitor coin cells presented very low equivalent series resistance, ~ 100% device storage and supply efficiency, then almost no Capacitance, Energy and Power lost after dozen thousand cycles (on the optimized cell). The Ragone plot contrasts our data with conventional capacitors, electric double-layer capacitor (EDLC) and batteries, fitting them well into the EDLC category. For our best understanding, the excellent electric contact of MC and Al current collector is the key parameter to achieve a minimal ESR, higher efficiency and longer lifetime. The detailed characterization of material and devices are presented herein, evidencing MC as promising materials for energy storage applications.

Ultrasound-assisted conversion of cellulose into hydrogel and functional carbon material

Microcrystalline cellulose (MCC) was fibrillated using an ultrasound probe to produce a hydrogel, which after freeze-drying and carbonisation under N2 atmosphere at elevated temperatures produced highly porous carbon. Ultrasound treatment in the absence of acid resulted in high aspect ratio, nanocrystalline cellulose due to fibrillation of the outer layers of the MCC fibre bundles, whereas in the presence of acid, cleavage of glycosidic bonds resulted in smaller aspect ratio fibres. Carbonisation of the acid-generated nanocrystalline cellulose samples at 800 °C provided the highest BET surface area of 917.0 m2/g, with over 18% pore volume in mesopores. The resulting high surface area carbon was able to absorb 100% of methylene blue in a solution having an initial concentration of 10 mg/L in 20 min which is comparable with many commercially available activated carbon products. Ultrasonication of microcrystalline cellulose resulted in nanocrystalline cellulose hydrogel which after freeze drying and carbonisation provided high surface area mesoporous carbon.

An ultra-high surface area mesoporous carbon prepared by a novel MnO-templated method for highly effective adsorption of methylene blue

Mesoporous carbon is considered as the most effective adsorbent for dyes with large molecule diameter. In this study, an ultra-high surface area mesoporous carbon was derived using a kind of new template precursors (manganese salts), i.e. manganese carbonate (MC), manganese oxalate (MO) and manganese acetate (MA). The XRD results demonstrated that after the pyrolysis of the mixture of manganese salts and poly(vinyl alcohol) (PVA) over 500 °C, MnO was only the Mn species on carbon and the particle sizes of the generated MnO were in the range of 1.92–15.11 nm, with the lowest value derived from MO. All prepared carbons presented evident mesoporous characteristics, with higher specific surface areas (SBET) at 2138 m2/g, mesopore volume (Vmeso) at 3.56 cm3/g, and mesopore ratios > 95%, together with the lowest and narrowest mesopore size distribution, for the MO-templated sample. The sample had high adsorption capacities for methylene blue, up to 1791 mg/g, and extremely fast adsorption rates with the adsorption equilibrium time within 1 min, which was significantly higher than previous studies. The results demonstrated that the novel MnO-templated method is very promising for the preparation of high surface area mesoporous carbon for highly effective adsorption of methylene blue.

Facile synthesis of mesoporous carbon from furfuryl alcohol-butanol system by EISA process for supercapacitors with enhanced rate capability

A smart, efficient and cost-effective strategy using modified evaporation induced self-assembly (EISA) is employed to synthesize mesoporous carbon (MC) with excellent textural parameters. Furfuryl alcohol is utilized as an alternative source of carbon precursor for the first time in EISA process in place of conventional EISA precursor, namely resol. Further n-Butanol, used as a co-structure directing agent during synthesis plays a crucial role in formation of a high surface area mesoporous carbon. The resulting carbon synthesized by modified EISA process shows a high specific surface area with large pore volume and more of ordered graphitic carbon. Wettability studies reveal that the surface functionalized mesoporous carbon film surface exhibits superior hydrophilic properties in comparison with non-functionalized mesoporous carbon film surface. It delivers a high specific capacitance of 151 F g−1 at a high current density of 50 A g−1 and shows excellent rate capability with 93% capacitance retention. It also exhibits good cyclic stability with capacitance retention of 96% after 10,000 cycles and delivers a stable energy density of 2.7 W h kg−1 by retaining a power density of 2516 W kg−1. The excellent electro-chemical performance of mesoporous carbon reported in the present study is attributed to the presence of high surface area of MC with large interconnected mesopores that allows unhindered flow of the electrolyte ions to the active surface sites. Benchmark studies reveal that the electro-chemical performance of mesoporous carbon being reported in this study is better than carbon electrode based commercial supercapacitors. Thus, the simple and unique strategy employed in the present study can be extended to synthesize carbon materials for other energy storage applications.

Roll-to-roll fabrication of high surface area mesoporous carbon with process-tunable pore texture for optimization of adsorption capacity of bulky organic dyes

Large-scale (multigram-to-kilogram) fabrication of soft-templated ordered mesoporous carbon (OMC) is enabled by roll-to-roll (R2R) processing via evaporation induced self assembly of Pluronic F127, oligomeric phenolic resin (resol), and tetraorthosilicate (TEOS) from ethanolic solution. The solution concentration, TEOS loading (etchable for microporous framework), and crosslinking temperature impact the pore structure. Here we demonstrate that mesoporous carbons with surface areas up to 2455 m2/g can be obtained under the proper processing conditions. Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS) and nitrogen adsorption–desorption isotherms reveal (i) suppressed framework shrinkage with increasing solution concentration during casting, (ii) improved long range order and higher surface area with increasing TEOS content up to 3:1 TEOS:resol, and (iii) enhanced porosity with crosslinking at 100 °C. These differences can be explained on the basis of block copolymer thermodynamics and mechanical reinforcement by silica. This family of OMCs are effective adsorbents for bulky aqueous organic dyes, such as methylene green (MG) and methyl blue (MB), with high adsorption capacities of 0.436 g MG/g OMC and 0.378 g MB/g OMC obtained. This R2R method provides a facile method to generate significant quantities of OMCs with tunable pore textures.

Unveiling Mesopore Evolution in Carbonized Wood: Interfacial Separation, Migration, and Degradation of Lignin Phase

Carbon porous structure can be generated by an activation process, either chemically or physically. However, it remains a challenge to understand the pore structure evolution especially in a physically thermal oxidation process. In this work, mesopore evolution is revealed in association with three distinct stages: phase separation, migration, and thermal degradation. Oxidation temperature (270–370 °C) and time (1–7 h) are employed to study the microstructure evolution in oxidative environment. Various characterization techniques including scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption, Raman and X-ray photoelectron spectroscopy have been used to investigate the structural and compositional change during thermal oxidation. High surface area mesoporous carbon is successfully manufactured from natural wood via this green technique, which could be applied to synthesize other highly porous carbon materials from similar biomass resources.

Magnesiothermal synthesis of nanostructured SiC from natural zeolite (clinoptilolite) and mesoporous carbon CMK-1

Magnesiothermal synthesis of nanosized SiC has been successfully achieved from a mixture of the natural zeolite clinoptilolite and a high-surface area mesoporous carbon CMK-1, synthesized by impregnating a mesoporous silica template MCM-48 with sucrose, followed by carbonization in argon and removal of the silica template. Magnesium powder was used to initiate the self-combustion reaction. Removal of the alkaline and alkaline earth exchangeable cations from the clinoptilolite by ion exchange with NH4+ was essential for a good yield of product, which is also dependent on the use of excess of carbon. TEM confirmed the nanostructure and size of the 15–25nm SiC product crystallites.

Platinum supported on mesoporous carbon as cathode catalyst for direct methanol fuel cells

Platinum nanoparticles supported on mesoporous carbon were obtained by an impregnation and reduction method with NaBH4 as the reducing agent. The high specific surface area mesoporous carbon was obtained by carbonization of a resorcinol-formaldehyde polymer with a cationic polyelectrolyte as a soft template. Surface characterization performed by transmission electron microscopy and powder X-ray diffraction showed a homogeneous distribution and high dispersion of the metal particles on the mesoporous support. The carbon-supported Pt catalyst was employed as cathode catalyst in a direct methanol fuel cell where a 30% increase in power density was obtained when compared to Pt supported on Vulcan carbon, under the same conditions.

Bio-mass derived mesoporous carbon as superior electrode in all vanadium redox flow battery with multicouple reactions

We first report the multi-couple reaction in all vanadium redox flow batteries (VRFB) while using bio-mass (coconut shell) derived mesoporous carbon as electrode. The presence of V3+/V4+ redox couple certainly supplies the additional electrons for the electrochemical reaction and subsequently provides improved electrochemical performance of VRFB system. The efficient electro-catalytic activity of such coconut shell derived high surface area mesoporous carbon is believed for the improved cell performance. Extensive power and electrochemical studies are performed for VRFB application point of view and described in detail.

Nitrogen doped carbon catalyzing acetylene conversion to vinyl chloride

Commercial production of vinyl chloride from acetylene relies on the use of HgCl2 as the catalyst, which has caused severe environmental problem and threats to human health because of its toxicity. Therefore, it is vital to explore alternative catalysts without mercury. We report here that N-doped carbon can catalyze directly transformation of acetylene to vinyl chloride. Particularly, N-doped high surface area mesoporous carbon exhibits a rather high activity with the acetylene conversion reaching 77% and vinyl chloride selectivity above 98% at a space velocity of 1.0 mL·min−1·g −1 and 200 °C. It delivers a stable performance within a test period of 100 h and no obvious deactivation is observed, demonstrating potentials to substitute the notoriously toxic mercuric chloride catalyst.

Facile Synthesis of Nitrogen-doped Porous Carbon for Selective CO2 Capture

Solid-state post-combustion CO2 sorbents have certain advantages over traditional aqueous amine systems, including reduced regeneration energy since vaporization of liquid water is avoided, tunable pore morphology, and greater chemical variability. We report here an ordered mesoporous nitrogen-doped carbon made by the co- assembly of a modified-pyrrole and triblock copolymer through a soft-templating method, which is facile, economic, and fast compared to the hard-template approach. A high surface area mesoporous carbon was achieved, which is comparable to the silica counterpart. This porous carbon, with a Brunauer–Emmett–Teller (BET) specific surface area of 804.5 m2 g-1, exhibits large CO2 capacities (298 K) of 1.0 and 3.1 mmol g-1 at 0.1 and 1 bar, respectively, and excellent CO2/N2 selectivity of 51.4. The porous carbon can be fully regenerated solely by inert gas purging without heating. It is stable for multiple adsorption/desorption cycles without reduction in CO2 capacity. These desirable properties render the nitrogen-doped hierarchical porous carbon a promising material for post-combustion CO2 capture.

Chiral Nematic Stained Glass: Controlling the Optical Properties of Nanocrystalline Cellulose-Templated Materials

Chiral nematic mesoporous materials decorated with metal nanoparticles have been prepared using the templated self-assembly of nanocrystalline cellulose (NCC). By adding small quantities of ionic compounds to aqueous dispersions of NCC and tetramethoxysilane (TMOS), the helical pitch of the chiral nematic structure could be manipulated in a manner complementary to the ratio of NCC/TMOS previously demonstrated by our group. We have studied the transformation of these ion-loaded composites into high surface area mesoporous silica and carbon films decorated with metal nanoparticles through calcination and carbonization, respectively. This general and straightforward approach to prepare chiral nematic metal nanoparticle assemblies may be useful in a variety of applications, particularly for their chiral optical properties.

Riboflavin adsorption onto multi-modal mesoporous carbon synthesized from polyethylene glycol 400

Multi-modal high surface area mesoporous carbon (MC4-400) was synthesized through hard-templating method using amorphous mesoporous silica (AMS) as a template and polyethylene glycol 400 (PEG-400) as a liquid carbon source. Adsorption performance was investigated on water-soluble riboflavin at 298, 313 and 323K. The equilibrium data were fitted to selected non-linear two-parameter adsorption isotherm models (Langmuir, Freundlich and Temkin) and three-parameter adsorption isotherm models (Koble-Corrigan, Redlich-Peterson, Sips and Toth). The resultant sum of error squares (SSEs) and coefficient of determination (r2) suggested that all selected isotherm models were applicable to represent the experimental data for the whole concentration range (10–50mgL−1). However, Redlich-Peterson model was not valid because the exponent g value was greater than 1. A two-stage batch adsorber has been designed based on the calculated Langmuir constants. A remarkable 23.3% reduction in adsorbent consumption was predicted for two-stage batch adsorber as compared to single-stage process.

Optimization of Dye-sensitized Solar Cells Consisting of Low-temperature Fabricated Mesoporous Carbon Counter Electrode

Carbon counter electrode was fabricated using high surface area mesoporous carbon (MC) as catalytic ma- terial at low temperature. The integral structure and the photovoltaic performances of dye-sensitized solar cells (DSC) consisting of the obtained carbon counter electrode were emphatically optimized. The results show that both contact interface among MC particles and that between carbon catalytic film and substrate are improved by adding Triton X100 into MC slurry, leading to an increase of 7.1% in the efficiency of DSC. With the increasing thickness of TiO2 film, the efficiency of DSC sharply increases at first and tends to stabilization later on. The change in the efficiency is the result of competition between the adsorption amount of dye and the transmission path of electron in the TiO2 film. The resistance of electrolyte is reduced by mixing tributyl phosphate into electrolyte, resulting in an increase of 23.1% in the efficiency of DSC. The optimum efficiency of DSC employing carbon counter electrode reaches 4.82%.