Production Of Carbon Materials Research Articles

Micro-mesoporous carbons form non-porous zinc-organic coordination compounds: Synthesis, structure and gas adsorption properties

A series of non-porous zinc-containing coordination compounds with mono- and polydentate ligands has been used to produce carbon materials with a hierarchical porous structure. Adjustment of the carbonization mode enables to increase the target product yield by an average of three times. The obtained carbons have a combination of micro- and mesopores with a pronounced maximum at 3.5 nm. The gas-sorption behavior of the obtained carbons has been studied over a wide range of temperatures and pressures. It has been established that the amount of excess adsorption for hydrogen and methane reaches 2.7 and 15 wt%, respectively. The extension of the proposed approach to the use of simple bimetallic complexes as precursors may be promising for obtaining effective catalysts based on a carbon matrix with controlled porosity and encapsulated nanoscale particles of a catalytically active metal.

Catalyst-Enhancing Hydrothermal Carbonization of Biomass for Hydrochar and Liquid Fuel Production-A Review.

The research impact of catalysts on the hydrothermal carbonization (HTC) process remains an ongoing debate, especially regarding the quest to enhance biomass conversion into fuels and chemicals, which requires diverse catalysts to optimize bio-oil utilization. Comprehensive insights and standardized analytical methodologies are crucial for understanding HTC's potential benefits in terms of biomass conversion stages. This review seeks to understand how catalysts enhance the HTC of biomass for liquid fuel and hydrochar production, drawing from the following key sections: (a) catalyst types applied in HTC processes; (b) biochar functionality as a potential catalyst; (c) catalysts increasing the success of HTC process; and (d) catalyst's effect on the morphological and textural character of hydrochar. The performance of activated carbon would greatly increase via catalyst action, which would progress the degree of carbonization and surface modification, alongside key heteroatoms. As catalytic HTC technology advances, producing carbon materials for thermochemical activities will become more cost-effective, considering the ever-growing demands for high-performance thermochemical technologies.

Laser irradiation of photothermal precursors - a novel approach to produce carbon materials for supercapacitors.

A wide array of carbon materials finds extensive utility across various industrial applications today. Nonetheless, the production processes for these materials continue to entail elevated temperatures, necessitate the use of inert atmospheres, and often involve the handling of aggressive and toxic chemicals. The prevalent method for large-scale carbon material production, namely the pyrolysis of waste biomass and polymers, typically unfolds within the temperature range of 500-700 °C under a nitrogen (N2 ) atmosphere. Unfortunately, this approach suffers from significant energy inefficiency due to substantial heat loss over extended processing durations. In this work, we propose an interesting alternative: the carbonization of photothermal nanocellulose/polypyrrole composite films through CO2 laser irradiation in the presence of air. This innovative technique offers a swift and energy-efficient means of preparing carbon materials. The unique interaction between nanocellulose and polypyrrole imparts the film with sufficient stability to retain its structural integrity post-carbonization. This breakthrough opens up new avenues for producing binder-free electrodes using a rapid and straightforward approach. Furthermore, the irradiated film demonstrates specific and areal capacitances of 159 F g-1 and 62 μF cm-2 , respectively, when immersed in a 2 M NaOH electrolyte. These values significantly surpass those achieved by current commercial activated carbons. Together, these attributes render CO2 -laser carbonization an environmentally sustainable and ecologically friendly method for carbon material production.

Towards Negative Emissions: Hydrothermal Carbonization of Biomass for Sustainable Carbon Materials.

The contemporary production of carbon materials heavily relies on fossil fuels, contributing significantly to the greenhouse effect. Biomass is a carbon-neutral resource whose organic carbon is formed from atmospheric CO2. Employing biomass as a precursor for synthetic carbon materials can fix atmospheric CO2 into solid materials, achieving negative carbon emissions. Hydrothermal carbonization (HTC) presents an attractive method for converting biomass into carbon materials, by which biomass can be transformed into materials with favorable properties in a distinct hydrothermal environment, and these carbon materials have made extensive progress in many fields. However, the HTC of biomass is a complex and interdisciplinary problem, involving simultaneously the physical properties of the underlying biomass and sub/supercritical water, the chemical mechanisms of hydrothermal synthesis, diverse applications of resulting carbon materials, and the sustainability of the entire technological routes. This review starts with the analysis of biomass composition and distinctive characteristics of the hydrothermal environment. Then, the factors influencing the HTC of biomass, the reaction mechanism, and the properties of resulting carbon materials are discussed in depth, especially the different formation mechanisms of primary and secondary hydrochars. Furthermore, the application and sustainability of biomass-derived carbon materials are summarized, and some insights into future directions are provided.

Preparation of porous carbon electrode materials from potassium hydroxide extract of lignite doped with nitrogen

Lignite is cheap, easy to obtain and rich in pores, so it was used as an electrode material for supercapacitors early. In this paper, Yimin lignite (YM) was used as raw material, and KOH was used to extract organic components. Melamine was adulterated into the extracted material for thorough mixing. The reaction mechanism and structural changes in it were explored. Experimental results and density functional theory (DFT) calculations showed that introducing nitrogen atoms into the coal-based activated carbon leads to a rearrangement of the carbon skeleton structure and changes the surface chemical environment. In this process, we adjust the porosity, specific surface area and discharge specific capacity of the produced carbon materials by changing nitrogen doping ratio, activation time and activation temperature. The excellent N-doped porous carbon material At-120 (activation time:120 min) was prepared with a high specific surface area (SBET: 3020 m2/g), abundant micropores (Vmic: 1.242 cm3/g), proper mesopores (Vmes: 0.182 cm3/g, Vmes ratio: 12.6 %), low impurity content, and high amount of N doping (6.43 wt%). These characteristics of At-120 enabled it to have a high specific capacitance value of 433.5 F/g at a current density of 1 A/g. The enhanced At-120 has 42.18 % higher specific capacitance than the undoped lignite alkali extract(LC).

Enhancing photocatalytic destruction of lignin via cellulose derived carbon quantum dots/g-C3N4 heterojunctions

Lignocellulosic biomass exhibits a promising potential for production of carbon materials. Nitrogen and phosphorus co-doped carbon quantum dots (N,P-CQDs) were fabricated via (NH4)2HPO4 assisted hydrothermal treatment of cellulose pulp fibers. The as-prepared N,P-CQDs were characterized by HRTEM, FTIR, fluorescence and UV–vis, and then incorporated into g-C3N4 (CN) through sonication and liquid deposition, forming N,P-CQDs/sonication treated g-C3N4 (C-SCN) composites, which were then explored as photocatalysts. The photocatalytic ability of C-SCN towards model lignin was further analyzed. The results showed that, the fluorescence intensity and photoluminescence performance of N,P-CQDs were much higher than that of CQDs; the heterojunction was successfully constructed between the composites of N,P-CQDs and SCN; the incorporation of N,P-CQDs enhanced the visible light absorption, but reduced the band gap of the composite heterojunction; the resultant photocatalysts exhibited a good photocatalytic ability of model lignin via catalyze the fracture of β–O–4′ ether bond and CC bond, i.e., the photocatalytic degradation ratio reached up to 95.5 %; and the photocatalytic reaction generated some valuable organics such as phenyl formate, benzaldehyde, and benzoic acid. This study would promote the high value-added utilization of lignocellulosic resources especially in the transformation of lignin, conforming the concept of sustainable development.

The effect of the pyrolysis temperature and biomass type on the biocarbons characteristics.

The conversion of biomass and natural wastes into carbon-based materials for various applications such as catalysts and energy-related materials is a fascinating and sustainable approach emerged during recent years. Precursor nature and characteristics are complex, hence, their effect on the properties of resulting materials is still unclear. In this work, we have investigated the effect of different precursors and pyrolysis temperature on the properties of produced carbon materials and their potential application as negative electrode materials in Li-ion batteries. Three biomasses, lignocellulosic brewery spent grain from a local brewery, catechol-rich lignin and tannins, were selected for investigations. We show that such end-product carbon characteristic as functional and elemental composition, porosity, specific surface area, defectiveness level, and morphology strictly depend on the precursor composition, chemical structure, and pyrolysis temperature. The electrochemical characteristics of produced carbon materials correlate with the characteristics of the produced materials. A higher pyrolysis temperature is shown to be favourable for production of carbon material for the Li-ion battery application in terms of both specific capacity and long-term cycling stability.

Sustainable Supercapacitor Electrode Based on Activated Biochar Derived from Preserved Wood Waste

Due to the inherent metals (Cu, As and Cr) in preserved wood waste (CCA-treated wood waste) that pose a risk to both the environment and human health, it is crucial to dispose of CCA-treated wood properly. Carbon materials have received widespread attention for their high porosity, renewability and simplicity of fabrication. This work presents a simple and effective process for producing carbon materials from leftover CCA-treated wood (chromated copper arsenate). Utilizing CCA-treated wood derived carbon (CCA-BC) and activating it with KOH (CCA-AC), electrode materials for supercapacitor applications were created and its electrochemical characteristics were investigated. The resulting material combines the conductivity of the metal in preserved wood with the good porosity provided by carbon materials. Compared with common wood biomass, carbon (W-BC) and common wood activated carbon (W-AC), CCA-BC and CCA-AC have better electrochemical properties. After being pyrolyzed at 600 °C for two hours, CCA-AC performed optimally electrochemically in 1 M Na2SO4 electrolyte, demonstrating a 72% capacity retention rate after 2000 charge and discharge cycles and a specific capacity of 76.7 F/g. This study provides a novel approach for the manufacture of supercapacitor electrodes, which also allows preserved wood waste an environmentally nondestructive form of elimination.

Polyethylene-derived high-yield carbon material for upcycling plastic wastes as a high-performance composite filler

In this study, to address environmental challenges stemming from plastic wastes, we produced carbon material derived from polyethylene (PE-C) using thermal oxidation and carbonization processes. Prior to thermal oxidation, e-beam irradiation was employed to enhance oxidation reactions which facilitated transformation of linear chains to cyclic ladder structures, resulting in a threefold increase in carbonization yield compared to conventional methods. Our analysis using XRD, Raman spectroscopy, XPS, and SEM revealed that PE-C exhibited a crystal structure similar to commercial CB (C-CB). However, it featured three times more oxygen functional groups on its surface and consisted of individual particles without forming aggregates or agglomerates. We incorporated PE-C into a PA6 polymer matrix to create composite materials with various compositions, systematically comparing their electrical, thermal, and mechanical properties to C-CB/PA6. PE-C outperformed C-CB in terms of mechanical properties (65 MPa vs. 41 MPa) due to its surface oxygen functional groups, uniform dispersion even at high loadings, and a rough surface. Moreover, PE-C exhibited a lower surface area, which reduced interfacial thermal resistance and consequently enhanced thermal conductivity, resulting in a 16 % improvement compared to C-CB at 30 wt%.

Porous carbon material production from microwave-assisted pyrolysis of peanut shell

Due to the complex porous structure, biochar usually has good adsorption capacity. Therefore, compared with direct combustion, conversion of peanut shell into biochar by pyrolysis is considered to be an environmentally friendly and efficient method for agricultural solid waste disposal. In this study, biochar production from microwave-assisted pyrolysis of peanut shell was detailed. The yields, surface topographies, and pore structures (pore size distribution and micropore volume) of biochars prepared at different pyrolysis temperatures (700, 750, 800, 850, 900, and 950 °C), microwave powers (350, 400, 450, 500, and 550 W), and residence times (0.5, 1.0, 1.5, 2.0, and 3.0 h) were elaborated. The results showed that the biochar yield gradually decreased and finally stabilized to around 30% while the specific surface area improved within the range of 4.68–67.29 m2/g when the pyrolysis temperature, microwave power, or residence time increased. Biochar with micropore was first obtained at pyrolysis temperature of 800 °C, microwave power of 500 W, and residence time of 2.0 h. This study further proposed quantitative relationships between the pore structures of peanut shell based biochars and experimental conditions (pyrolysis temperature, microwave power and residence time). The results presented in this study can provide guidance for the reuse of peanut shell and the production of porous biochar. The peanut shell biochar prepared in this study can be used in soil remediation, air purification, liquid purification and other fields for its porous structural characteristics.

Electrochemical splitting of methane in melts: Producing and tuning high-value carbon materials with controllable morphology

Catalytic decomposition of methane offers a viable solution for producing pure hydrogen and nanocarbon without emitting carbon dioxide. However, conventional thermal catalytic processes and catalysts have limitations in terms of poor carbon quality and catalyst deactivation due to carbon deposition. The newly developed electrochemical splitting of methane (ESM) in molten salt has emerged as a promising alternative that allows for the separate production of hydrogen at the anode and carbon deposition at the cathode. In this study, hydrogen produced via ESM while generating nanocarbon with diverse structures through manipulations of the cathode material and kinetics. Carbon nanotubes grown on Ni cathode, possessing high specific surface area and abundant functional groups, displayed excellent adsorptive capacity for dye adsorption. The open hollow nanocarbon grown on the Ag cathode displayed good capacitance performance. ESM technology has immense potential to enhance the utilization value of carbon by-products and the commercial production of green hydrogen.

Production of High Surface Area Activated Carbon from Peanut Shell by Chemical Activation with Zinc Chloride: Optimisation and Characterization

The potential of peanut shell as a precursor to produce activated carbon by chemical activation with ZnCl2, and the effect of activation variables were investigated using response surface methodology. Activation variables examined were temperature, hold time and impregnation ratio; among these, impregnation ratio and temperature were found to most affect the final characteristics of the produced activated carbon. The activation process was mapped, using design of experiments, and the optimum activation conditions were found to be a temperature of 485 °C, with a hold time of 15 min and an impregnation ratio of 1.7. Under the optimised conditions, an activated carbon with a relatively high surface area of ~ 1700 m2/g was produced, at a yield of 47%. Moreover, the carbon exhibited a relatively high density, ranging from 1.455 g/cm3 to 1.750 g/cm3, as well as a low ash content below 1% and a high fixed carbon content above 86%. SEM analysis and FTIR characterisation revealed the heterogenous nature of the produced carbon materials. The developed materials, with potential as adsorbents, removed up to 99.8% of a target dye (methyl orange) depending on their available surface area. Hence, through the insights gained, an optimised carbon is produced, demonstrating the potential to tailor activated carbon materials produced from waste biomass.

Effect of secondary gas-phase reactions (SGR) in pyrolysis of carbon feedstocks for anisotropic carbon materials production – 3: Modifying non-coking coal tar through co-pyrolysis of coal with linear low-density polyethylene and high-impact polystyrene

This work focuses on co-pyrolysis experiments of Utah Sufco coal with linear low-density polyethylene (LLDPE) and high-impact polystyrene (HIPS). These two plastic types have differing pyrolysis chemistries and have different hydrogen transfer behavior. Similar to earlier work in this series of papers, controlled secondary gas-phase reactions during pyrolysis were used to induce cracking and condensation reactions among the pyrolytic tar species. Co-pyrolysis tests were performed with feed plastic percentages ranging from 10 to 20 wt % and pyrolysis SGR temperatures ranging from 800 to 900° C. Analyses of the intermediate tar products showed that oxygen contents and aromaticity were substantially different, depending on the plastic, and resulting pitch softening points and mesophase contents also varied greatly depending on the starting plastic feedstock used. Most of the synergies observed in the co-pyrolysis results were negative, except for the oxygen content. Oxygen contents were higher than expected when LLDPE was used, resulting in reactive pitches with softening points >350° C. On the other hand, oxygen contents were lower than expected when HIPS was used, resulting in less reactive pitches. Ultimately, only the HIPS/coal samples created at the SGR temperature of 900° C had reasonable softening points at or under 350° C, making them the only samples created in this work potentially suitable for mesophase pitch-based carbon fiber production. The success in creating fusible mesophase pitches from co-pyrolyzing HIPS with Utah Sufco coal is likely attributed to the fact that polystyrene is a stronger hydrogen acceptor rather than donor, which should facilitate more cracking rather than stabilizing tar oxygen functional groups, making the tar species ultimately less reactive during thermal conversion to mesophase pitch.

Exploring synergistic effects in physical-chemical activation of Acorus calamus for water treatment solutions

The research proposed a novel method of obtaining sorption material from readily available Acorus calamus biomass through a combination of physical and chemical activation processes. The material with the highest specific surface area (1652 m2 g−1) was obtained by physical activation with CO2, followed by chemical activation with KOH. Reversing the order of activation methods resulted in a lower specific surface area (1014 m2 g−1) of the carbon sample. Chemical activation produced activated carbon with a surface area of 1066 m2 g−1-, while physical activation produced 390 m2 g−1. This confirms the synergistic effect of combining the two activation methods for biocarbon. It was observed that physical activation with CO2 generates a diverse range of pores, including meso- and macropores, while chemical activation induces the formation of micropores. In contrast, reversing the order of these processes leads to the degradation of the porous structure. The application of physical-chemical activation with synergistic effects represents a significant advancement in producing high-quality activated biocarbon for various applications, such as wastewater treatment and energy storage. The combination of the two activation methods resulted in a synergistic effect, leading to the production of carbon material of higher quality. Additionally, the diversified pore sizes will enable the sorption of various pollutants in the aquatic environment and air pollutants, where gas particles are much smaller.

Aspergillus niger fermentation residues application to produce biochar for the anode of lithium-ion batteries

Aspergillus niger is widely applied in the fermentation industry, but produce abundant mycelium residues every year. As a kind of solid waste, mycelium residues seriously affect the environment. How to manage and utilize this solid waste is a problem for the fermentation industry. It was reported that many kinds of biomass could be utilized to produce carbon materials, which would be further used to produce lithium-ion rechargeable batteries (LIBs). Here, porous biochar was prepared from A. niger mycelial residues and further used as an anode for LIBs. Since the A. niger mycelium contains abundant nitrogen (5.29%) from its chitosan-dominated cell wall, and silicon (9.63%) from perlite filter aid, respectively, the biochar presented an excellent cycle stability and rate performance when applied as the anode of LIBs. The conclusion of this research shows the wide application prospect of fungal fermentation residues as carbon precursors in energy storage devices. Meanwhile, this investigation provides an alternative management method for A. niger mycelium residues, with which the mycelium residues could be effectively recycled to avoid resource waste and environmental pollution.

A facile procedure to improve the performance of food-waste-derived carbons in sodium-ion batteries

The anode of Na-ion batteries under development is dominated by carbon materials, especially hard carbons with poorly organized structures. The production of carbon materials by pyrolysis of food waste is less expensive and more environmentally friendly than from pure organic compounds. In this work, the sulfuric acid pre-treatment of ground coffee grains before carbonization is evaluated as a simple but efficient tool to improve the electrochemical performance of the resulting carbon for the anode of sustainable Na-ion batteries. The carbon product shows a significant reduction in inorganic impurities and a decrease in crystallinity, which results in a reversible capacity close to 33 % higher, enhanced first-cycle efficiency, and better kinetic response than the non-pre-treated materials. Thus, reversible capacities at C/10 increase from ca. 150 mAhg−1 to 200 mAhg−1 after acid treatment, and the capacity of the non-acid-treated samples falls to negligible values at 2C kinetics, in contrast with significant retention of the acid-treated one.

Atomistic Insights into Early-Stage Oxidation of χ-Fe5C2 and the Dependence on the Surface Structure

Iron carbides play a crucial role in many industrial fields, such as the steel industry, catalysis, carbon material production, and so on. One of the main challenges is that iron carbides are highly susceptible to being oxidized under service conditions, which can significantly reduce the performance and retard their industrial applications. However, the complex chemical structure of iron carbide materials and the dynamic nature of the Fe–C–O system under reactive conditions, such as the Fischer–Tropsch synthesis condition, hindered the understanding of the oxidation process. In this paper, structure evolution of the early-stage oxidation of χ-Fe5C2 was investigated through reactive force field molecular dynamics simulations. The impacts of surface structure, oxygen coverage, temperature, and particle size were systemically explored. It was found that the oxidation rate was not only related to the surface carbon content but also to the homogeneity of the subsurface. Meanwhile, the dynamic structure transformation during oxidation was analyzed by various correlation functions. The mechanism of counter-direction migration of surface atoms during the oxidation process was illustrated, where carbon atoms migrate to the bulk region and iron atoms migrate to the surface. Our study reveals the atomistic dynamic mechanism of χ-Fe5C2 oxidation, which offers crucial insights for catalyst oxidation and iron carbide materials.

Green Production of Biomass-Derived Carbon Materials for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) with a high energy density have been regarded as a promising energy storage device to harness unstable but clean energy from wind, tide, solar cells, and so on. However, LSBs still suffer from the disadvantages of the notorious shuttle effect of polysulfides and low sulfur utilization, which greatly hider their final commercialization. Biomasses represent green, abundant and renewable resources for the production of carbon materials to address the aforementioned issues by taking advantages of their intrinsic hierarchical porous structures and heteroatom-doping sites, which could attribute to the strong physical and chemical adsorptions as well as excellent catalytic performances of LSBs. Therefore, many efforts have been devoted to improving the performances of biomass-derived carbons from the aspects of exploring new biomass resources, optimizing the pyrolysis method, developing effective modification strategies, or achieving further understanding about their working principles in LSBs. This review firstly introduces the structures and working principles of LSBs and then summarizes recent developments in research on carbon materials employed in LSBs. Particularly, this review focuses on recent progresses in the design, preparation and application of biomass-derived carbons as host or interlayer materials in LSBs. Moreover, outlooks on the future research of LSBs based on biomass-derived carbons are discussed.

Synthesis of nitrogen-doped hierarchically porous carbons with ordered mesopores from liquefied wood: Pore architecture manipulation by NH4Cl for improved electrochemical performance

Functional porous carbon materials have attracted significant attentions due to their unique characteristics. Herein, the synthesis of N-doped hierarchically porous carbon (N-HPC) with ordered mesopores from liquefied wood is reported through a soft-templating and chemical blowing method with the assistance of NH4Cl to regulate their pore architectures. The NH4Cl strengthens the interactions between the carbon sources and soft templates in the hydrothermal process to produce carbon materials with highly ordered mesostructure after carbonization. Then, the obtained carbon is ground with NH4Cl, where NH4Cl releases NH3 and HCl upon heating to introduce N atoms and micropores into the carbon structures. Highly ordered p6mm mesostructure, high specific surface area (1160 m2 g−1) and nitrogen content of 3.75 wt% are obtained with the assistance of NH4Cl, which together affords them enhanced electrochemical performance for supercapacitors. The obtained N-HPC electrode displays a specific capacitance of 282 F g−1 at 1 A g−1 and good rate capability.

Green and easy synthesis of P-doped carbon-based hydrogen evolution reaction electrocatalysts

In this study, efficient electrodes for the hydrogen evolution reaction (HER) based on low-cost and metal-free carbon catalysts are presented. Phytic acid, a biosourced molecule containing carbon (C) and phosphorus (P), was found to be an excellent precursor for producing carbon materials with high P content, depending on the carbonization temperature, from 27.9 wt% at 700 °C to 7.3 wt% at 1000 °C. A green and easy route to produce P-doped carbon materials by heat treatment of this biosourced precursor without the need for additional reagents is thus proposed. We show that the conversion of P-O-type groups into P-C-type species is of paramount importance for improving the catalytic activity in HER of P-doped carbon materials. P-C-type groups appear to be the key factor in the electrocatalytic activity, reaching an onset potential of - 0.27 V. This study sheds light on the origin of the catalytic activity of P-doped carbons, in which P is expected to modify the homogenous distribution of the electron density of undoped carbons and increase their catalytic performance.