Synthesis Of Porous Carbon Research Articles

Metal-organic framework-based materials for solar-driven interfacial evaporation

As a sustainable and green approach, solar-driven interfacial water evaporation (SIE) can recover clean water from diverse water resources such as seawater and wastewater by converting solar energy into heat energy, paving the way to addressing the increasingly severe water shortage. In recent years, metal–organic frameworks (MOFs) have been applied for constructing the evaporator for SIE, considering their merits such as large specific surface area, tunable component and structure, and high porosity. More importantly, MOFs materials have expanded their application in the synthesis of porous carbon, metal oxides/sulfides/carbides, and MOFs composites, which not only may preserve the merits of MOFs but also possess other functions. In this review, the latest developments regarding the solar evaporators designed by MOFs-based materials (including MOFs, MOFs-derivatives, and MOFs composites) is summarized and systematically discussed. The roles of MOFs-based materials in evaporation systems and the emerging applications of the evaporation systems are also highlighted. Ultimately, the challenges and perspectives of the MOFs-based materials used for designing of SIE systems are also presented.

Biomass nanoarchitectonics for porous carbon materials with exceptionally high mesoporous ratio through urea-regulated co-activation strategy and their application in supercapacitors

The synthesis of porous carbon with a high mesoporous ratio is a significant challenge, particularly when utilizing heteroatom-enriched biomass precursors as feedstock. In this work, bio-based porous carbon with a 95 % mesoporous ratio was synthesized by using chitosan and lignosulfonates as biomass precursors, combined with a urea-regulated co-activation strategy. The high mesoporous formation of porous carbon can primarily be attributed to four factors: (1) the formation of a cross-linked 3D network, (2) the generation of nitrogen-containing gas resulting from urea decomposition, (3) the depolymerization of LS and (4) KOH-activated carbonization. Besides, the specific surface area and mesoporous ratio can be adjusted by varying the ratio of KOH to urea, ranging from 1793 m2 g−1 to 2876 m2 g−1 and from 22 % to 95 %, respectively. The application of density functional theory calculations reveals that the synergistic effect of N/S co-doping facilitates rapid ion adsorption reactions on carbon surfaces, further improving the electrochemical performance. As carbon electrode materials for supercapacitors in a three-electrode device, the capacitance reaches up to 263 F g−1 at 1 A g−1. The symmetric supercapacitors fabricated using CS@LS/C-800–1:0.5 achieved an impressive energy density of 17.8 Wh·kg−1 at a power density of 300.6 W kg−1, along with a remarkable capacitance retention rate of 96.6 %. This strategy provides a novel insight into enhancing the mesoporous ratio of bio-based porous carbon materials, thereby significantly broadening the application scope of biomass materials.

Synthesis of Porous Carbons from Candlenut Shells Using Various Types of Activators for Environmentally Friendly Supercapacitors

Porous carbon is one of the promising electrode materials for supercapacitors due to its unique and engineerable microstructural properties. The study of the synthesis of porous carbon from waste biomass is very important due to the abundance of natural resources, low cost production and contribute to solving environmental problems. In this study, porous carbons derived from candlnut shell with various type of activator was studied the chemical structural, morphological and electrochemical properties then evaluated as electrodes for supercapacitor. We have been successfully synthesized of porous carbon from candlenut shells using three steps of the process, i.e.: carboni-zation, activation and calcination. Carbonization was carried out at 700°C in a furnace using a closed crucible to minimize the oxygen. The chemical activation conducted using three types of activators, i.e. ZnCl2, H3PO4 and KOH then calcination process by heated at 800°C for 1 h under Ar flow. The results of the Fourier-transform infrared (FTIR) analysis show that the carbonization process increases the content of aromatic C=C functional groups and reduce the OH, C-H, C-O and C=O functional groups. The carbonization process has also increased the electrical conductivity of the sample around 0.8525 S/m. The results of Scanning Electron Microscope (SEM) images can be observed that the activation process of carbon has formed which was indicated by the appearance of many pores on the surface area of carbon. N2 adsorption/desorption isotherms (Brunauer–Emmett–Teller (BET)) characterization was indicated that the porous carbon is dominated by mesoporous with a pore size around 2-50 nm. BET characterization also can be determined the surface area of porous carbon around 477 m2/g for ZnCl2, 636 m2/g for H3PO4, and 681 m2/g for KOH. This synthesized materials are further employed in a symmetric supercapacitor using simple glass cell. The best performance of supercapacitor achieved by KOH porous carbons with 16.30 F/g of specific capacitance, 2.26 Wh/kg of energy density and 1038 W/kg of power density.

Construction of honeycomb-like N-doped porous carbon framework with effective aperture distribution toward advanced supercapacitors and sodium-ion batteries

Smart synthesis of porous carbon with appropriate aperture distribution and high area utilization still retains an enormous challenge for efficient charge storage. Herein, a simple freeze-drying along with subsequent one-step carbonization/activation process is ingeniously devised to fabricate honeycomb-like nitrogen-doped porous carbon (NPC) framework with high-level active N/O-functional groups and hierarchical porous structure including substantial ultra-micropores (<0.7 nm). The underlying formation mechanism of such porous NPC framework is tentatively proposed. By finely regulating the dosage of NaHCO3, the optimized NPC (i.e., NPC114) is endowed with ultra-high surface area utilization of ∼26.4 μF/cm2 at 1 A/g in KOH electrolyte, which is close to theoretical value of electrochemical double-layer capacitance (15 – 25 μF/cm2), and even larger than the case (∼22.4 μF/cm2) with H2SO4 electrolyte due to the inaccessible ultra-micropores by SO42− of larger size. Similarly, as for the organic system, the as-prepared NPC115 with higher meso- and macropore surface area exhibits higher energy density of 22.36 Wh/kg than other counterparts. Furthermore, NPC114, when evaluated as anode material for sodium-ion batteries, exhibited more attractive high-rate Na+-storage properties as well. The in-depth understanding into intrinsic relationship between aperture distribution and electrochemical behaviors will provide meaningful guidance for electrode material design.

Harnessing NaNH2 as a dual-function activator for synthesis of porous carbon and its impact on enhanced supercapacitor performance: a review

Harnessing NaNH2 as a dual-function activator for synthesis of porous carbon and its impact on enhanced supercapacitor performance: a review

Natural N/O/S co-doped defect-rich functional carbon materials for aqueous supercapacitors: Effect mechanism of N-containing functional groups on chemical activation

The efficient synthesis of porous carbons with a micro-mesoporous composite structure from low-cost, multi-source biomass was of significant importance for the fabrication of carbon-based supercapacitors. A novel method for the preparation of micro-mesoporous composite carbon materials by co-pyrolysis of multi-source biomass coupled with KOH activation was proposed in this study. The N, O and S co-doped micro-mesoporous composite carbon materials were synthesized using the bamboo and spiral algae as the precursors and KOH as the activator. Spiral algae, as the main source of heteroatoms, played multiple roles (pore forming agent, dopant and enhancer) in the co-pyrolysis process. The enhanced effect of heteroatom doping on KOH activation facilitated the formation of microporous structures. The KCA-500–2 exhibited a porous structure dominated by micropores, with a specific surface area (SSA) of 2421.85 m2/g. At 0.5 A/g, KCA-500–2 displayed an excellent capacitance of 460F/g and outstanding rate performance (73.5 %). The assembled aqueous symmetric supercapacitor (KCA//KCA) demonstrated a maximum energy density of 19.09 Wh/kg at a power density of 150 W/kg. In addition, KCA//KCA attained 97.96 % capacitance retention after 9,000 cycles. This work revealed the synergistic mechanism between N-containing functional groups and KOH activation, suggesting a theoretical guidance for the synthesis of high-performance supercapacitors.

Synthesis of porous carbons for the fixing of cationic molecules in aqueous solution

In Africa, the calyxes of the Hibiscus sabdariffa are widely used to produce a fresh fruit juice, known in Benin as bissap. The stems from this production have no potential use and are therefore an environmental problem. The parietal composition of these stalks revealed a high level of lignin (31 ± 1 %) and cellulose (35 ± 1 %). They can therefore be converted into activated carbon for various applications. In this study, the stems were transformed into activated carbons at moderate temperature using orthophosphoric acid (H3PO4) as the activating agent. The physicochemical, structural, and textural properties were determined. Adsorption kinetics and isotherms were studied and modelled. Porous carbons give specific surface areas equal to 1066 and 1053 m2.g−1 respectively for 2:1 and 4:1 ratios according to the B.E.T-Rouquerol model. Similarly, the said porous carbons give specific surface areas equal to 991 and 975 m2.g−1 respectively for 2:1 and 4:1 ratios according to the 2D-NLDFT model. Using the latter model, the pore size distribution is predominantly microporous, with the Vµ/VT (%) ratio increasing to 56 %. Thermogravimetric analysis of the porous coals showed favourable fixed carbon levels (≈ 60 %). The adsorption kinetics of methylene blue on activated carbons is governed by the pseudo-second order kinetic model indicating that the dye adsorption process is globally controlled by chemisorption. The results of the modelling of the methylene blue adsorption isotherms shown that the Langmuir model is the most credible model that best describes these experimental results, with 588 and 526 mg.g−1. These activated carbons are good candidates for the development of bio-sourced filters for the treatment of industrial wastewater.

Leveraging porosity and morphology in hierarchically porous carbon microtubes for CO2 capture and separation from humid flue gases

Leveraging porosity, surface chemistry and morphology of porous carbons play a critical role in CO2 capture performance. However, the effective and sustainable synthesis of porous carbons with well-interconnected hierarchical pore structure, high-proportioned micropores and high yield remains a huge challenging by a mild one-step chemical activation without damaging the natural unique nanostructure. Here, we proposed a green and sustainable strategy to fabricate porous carbons with tailorable porosity and unique tubular structure by an inorganic dynamic porogen of CuCl2. The dynamic activation mechanism of CuCl2 was explored in detail. In particular, the hierarchical porosity with a high-proportioned narrow micropores can be finely tuned without sacrificing the natural tubular morphology. Importantly, the resultant porous carbon adsorbents have an excellent resistance to water vapor, which can capture CO2 from humid flue gases with satisfactory adsorption capacity and selectivity. The HPCM-3 can achieve the best CO2 uptakes of 4.05 and 2.05 mmol/g under 100 kPa at 25 and 50 °C, respectively. Such superior CO2 adsorption behaviors can be well maintained even at high humidity of 70 %, and hardly decay with the enhancement of humidity. This route provides a promising avenue for developing the practical trace CO2 carbon-based adsorbents on a large scale to sieve CO2 from humid flue gases.

Potential Development of Porous Carbon Composites Generated from the Biomass for Energy Storage Applications.

Creating an innovative and environmentally friendly energy storage system is of vital importance due to the growing number of environmental problems and the fast exhaustion of fossil fuels. Energy storage using porous carbon composites generated from biomass has attracted a lot of attention in the research community. This is primarily due to the environmentally friendly nature, abundant availability in nature, accessibility, affordability, and long-term viability of macro/meso/microporous carbon sourced from a variety of biological materials. Extensive information on the design and the building of an energy storage device that uses supercapacitors was a part of this research. This study examines both porous carbon electrodes (ranging from 44 to 1050 F/g) and biomasses with a large surface area (between 215 and 3532 m2/g). Supposedly, these electrodes have a capacitive retention performance of about 99.7 percent after 1000 cycles. The energy density of symmetric supercapacitors is also considered, with values between 5.1 and 138.4 Wh/kg. In this review, we look at the basic structures of biomass and how they affect porous carbon synthesis. It also discusses the effects of different structured porous carbon materials on electrochemical performance and analyzes them. In recent developments, significant steps have been made across various fields including fuel cells, carbon capture, and the utilization of biomass-derived carbonaceous nanoparticles. Notably, our study delves into the innovative energy conversion and storage potentials inherent in these materials. This comprehensive investigation seeks to lay the foundation for forthcoming energy storage research endeavors by delineating the current advancements and anticipating potential challenges in fabricating porous carbon composites sourced from biomass.

Soft template-induced self-assembly strategy for sustainable production of porous carbon spheres as anode towards advanced sodium-ion batteries

Doped porous carbon is a prominent sodium anode material with high specific surface area (SSA) and abundant pore structure. Compared with the traditional “hard template” technique for the synthesis of porous carbon, the “soft template” method offers a more efficient synthesis process and simplified template removal. In response to the urgent need for eco-friendly synthesis methods for functional doping, our research introduces an innovative method using biomass-derived tannic acid as a precursor. We have successfully synthesized N/S double-doped porous spherical carbon materials (DF-N/S) through a self-assembly process driven by hydrogen bonding and solvent evaporation. As an anode material for sodium-ion batteries (SIBs), DF-N/S demonstrates superior electrochemical performance, achieving a specific capacity of 327.04 mAh g−1 at a current density of 0.05 Ag-1 in ether-based electrolytes. The remarkable sodium storage efficiency of DF-N/S has been thoroughly examined through kinetic analyses and ex-situ characterization methods. This study aims to provide a sustainable and widely adaptable method for the soft template production of doped carbon, while also shedding light on the intricacies of energy storage mechanisms in both ether/ester-based electrolytes.

A review on porous carbon synthesis processes and its application as energy storage supercapacitor

In India, there is a plenty of biomass generating from the various sources like industry, agriculture etc. The thermochemical conversion output products are becoming more familiar in the field of energy storage like fuel cells, supercapacitors and batteries. Because of their high-power density and extended life cycle, supercapacitors are playing an increasingly significant role in the energy storage sector. Supercapacitors have seen many advances in recent years. The most popular electrode material for supercapacitors is carbon, and studying carbon is important for creating new kinds of supercapacitors. This article describes the materials usually utilized for carbon electrodes and the energy storage techniques of supercapacitors. The most widely used carbon materials and their uses in the field of supercapacitors are introduced in the section on carbon electrode materials. Ultimately, the trajectory of advancement for carbon-based supercapacitors is anticipated. Supercapacitors have made a lot of advancements lately. This paper describes the carbon production technologies, electrode preparation for the energy storage supercapacitor, electrolytes and various separators were discussed.

Eggshell as a biotemplate for the synthesis of layered porous carbon by co-pyrolysis with eucalyptus leaves

Based on its substantial specific surface area (SSA), quick ion transport path, and excellent pore structure, biomass carbon is a common ingredient in energy storage materials. In this study, hierarchical porous carbon was fabricated by the hard template method, using eucalyptus leaves (EL) as raw material, eggshells (ES) obtained from biomass waste act as a green biotemplating agent, and through co-pyrolysis technology to acquire high-value biomass carbon materials. A large SSA with a hierarchical porous structure displayed a honeycomb appearance obtained by adding eggshells in appropriate proportions. The ELES0.25 electrodes demonstrated a specific capacitance (Cs) of 310 F g−1 (0.5 A g−1) and 232 F g−1 (20 A g−1) in a three-electrode system, which displayed a capacitance retention of 74.8% with an outstanding electrochemical stability. The assembled ELES0.25//ELES0.25 symmetric supercapacitor displays a desirable energy density of 7.35 Wh kg−1 at a power density of 65 W kg−1 and preserves a capacitance retention of 97.38% after a charge/discharge cycle for 10,000 times. This research on ES acts as the biological template for assisted pyrolysis synthesis of porous carbon and proposes a novel approach for the clean and effective use of biomass waste.

Sustainable Synthesis of Porous Biomass-Derived Carbon from Tecoma capensis for High Performance Supercapacitors: Characterization and Electrochemical Evaluation

Biowaste carbon products possess interesting physico-chemical properties and are cost-effective due to their remarkable characteristics. Biomass carbon derived from Tecoma capensis (TCL) was processed using pyrolysis at a controlled temperature in an eco-friendly, innovative and sustainable way to develop biomass-derived carbon material. The aim of this study is to demonstrate the facile synthesis of porous carbon compounds from biowaste and evaluate their use in supercapacitors. Various analytical methods, such as structural analysis, morphological studies and electrochemical studies, have been employed to characterize the carbon material generated from biomass. Electrochemical performance evaluation was conducted through cyclic voltammetry and galvanostatic charge-discharge studies utilizing 1 M H2SO4 and 1 M KOH aqueous electrolyte, which exhibited a specific capacitance of 238 F g-1. The outcomes of the studies suggested that the eco-friendly, straightforward process can be utilized to prepare biomass carbon for the electrochemical energy storage applications in an efficient and sustainable manner.

Waste Coffee Ground-Derived Porous Carbon for Neurochemical Detection.

We present an optimized synthetic method for repurposing coffee waste to create controllable, uniform porous carbon frameworks for biosensor applications to enhance neurotransmitter detection with fast-scan cyclic voltammetry. Harnessing porous carbon structures from biowastes is a common practice for low-cost energy storage applications; however, repurposing biowastes for biosensing applications has not been explored. Waste coffee ground-derived porous carbon was synthesized by chemical activation to form multivoid, hierarchical porous carbon, and this synthesis was specifically optimized for porous uniformity and electrochemical detection. These materials, when modified on carbon-fiber microelectrodes, exhibited high surface roughness and pore distribution, which contributed to significant improvements in electrochemical reversibility and oxidative current for dopamine (3.5 ± 0.4-fold) and other neurochemicals. Capacitive current increases were small, showing evidence of small increases in electroactive surface area. Local trapping of dopamine within the pores led to improved electrochemical reversibility and frequency-independent behavior. Overall, we demonstrate an optimized biowaste-derived porous carbon synthesis for neurotransmitter detection for the first time and show material utility for viable neurotransmitter detection within a tissue matrix. This work supports the notion that controlled surface nanogeometries play a key role in electrochemical detection.

Beyond Conventional Carbon Activation: Creating Porosity without Etching Using Cesium Effect.

Facile synthesis of porous carbon with high yield and high specific surface area (SSA) from low-cost molecular precursors offers promising opportunities for their industrial applications. However, conventional activation methods using potassium and sodium hydroxides or carbonates suffer from low yields (<20%) and poor control over porosity and composition especially when high SSAs are targeted (>2000 m2 g-1) because nanopores are typically created by etching. Herein, a non-etching activation strategy is demonstrated using cesium salts of low-cost carboxylic acids as the sole precursor in producing porous carbons with yields of up to 25% and SSAs reaching 3008 m2 g-1. The pore size and oxygen content can be adjusted by tuning the synthesis temperature or changing the molecular precursor. Mechanistic investigation unravels the non-classical role of cesium as an activating agent. The cesium compounds that form in situ, including carbonates, oxides, and metallic cesium, have extremely low work function enabling electron injection into organic/carbonaceous framework, promoting condensation, and intercalation of cesium ions into graphitic stacks forming slit pores. The resulting porous carbons deliver a high capacity of 252 mAh g-1 (567 F g-1) and durability of 100000 cycles as cathodes of Zn-ion capacitors, showing their potential for electrochemical energy storage.

Design of anti-saponification Ca-based catalyst with porous-shell structure from crustacean waste for biodiesel production

The rapid development of the biodiesel industry is of significant importance for achieving carbon emission reduction in the transportation sector. However, the presence of trace amounts of water in the feedstock during biodiesel synthesis may lead to severe saponification reactions, thereby reducing the yield of fatty acid methyl esters. In this study, based on our exploration of the characteristic of porous carbon to absorb moisture from the environment, we synthesized a CaO catalyst with porous carbon coating via discarded shrimp shell biomass. Because the carbonization temperature of organic matter in shrimp shells is lower than the decomposition temperature of CaCO3, the CO2 generated during pyrolysis can erode the pyrolytic carbon and form porous structure. The mesoporous carbon shell facilitates the diffusion of oil and methanol molecules while adsorbing moisture in the alcohol phase. This structure effectively minimizes the interaction between CaO and water, thereby suppressing saponification reactions and ensuring the smooth progression of the desired transesterification reaction. Through a series of physicochemical characterizations, the structure and water absorption performance of the catalyst were confirmed. The as-prepared CaO@PC-900 catalyst demonstrated the ability to maintain a biodiesel yield of over 85% in a reaction system with a water content of 3%, significantly surpassing the performance of commercial CaO and previously reported Ca-based solid bases. This work provides a new approach to the design of anti-saponification transesterification catalysts, while also offering a novel pathway for the synthesis of porous carbon from discarded crustacean biomass.

S/N/O-Enriched Carbons from Polyacrylonitrile-Based Block Copolymers for Selective Separation of Gas Streams.

A series of polyacrylonitrile (PAN)-based block copolymers with poly(methyl methacrylate) (PMMA) as sacrificial bock were synthesized by atom transfer radical polymerization and used as precursors for the synthesis of porous carbons. The carbons enriched with O- and S-containing groups, introduced by controlled oxidation and sulfuration, respectively, were characterized by Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectrometry, and their surface textural properties were measured by a volumetric analyzer. We observed that the presence of sulfur tends to modify the structure of the carbons, from microporous to mesoporous, while the use of copolymers with a range of molar composition PAN/PMMA between 10/90 and 47/53 allows the obtainment of carbons with different degrees of porosity. The amount of sacrificial block only affects the morphology of carbons stabilized in oxygen, inducing their nanostructuration, but has no effect on their chemical composition. We also demonstrated their suitability for separating a typical N2/CO2 post-combustion stream.

Nanoarchitectonics of low process parameter synthesized porous carbon on enhanced performance with synergistic interaction of redox-active electrolyte for supercapacitor application

To develop materials of lower embodied energy and materials footprint for energy storage industry, the present work reports synthesis of porous carbon from a waste wetland weed (wild sugarcane) using low process parametric conditions (temperature and impregnation ratio) and their electrochemical capacitive (synonymously known as supercapacitors) charge storage performance in aqueous and redox active electrolytes. The phase, surface chemistry, physical surface, and morphology of the porous carbon thus developed are studied in detail using X-ray diffraction, gas adsorption measurements, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy techniques. Porous carbon synthesized at 500 °C, with the activator ZnCl2, resulted in a combination of micro and meso pores and a specific surface area ∼1294 m2 g−1. The optimized electrodes show outstanding energy storage performance, viz. specific capacitance of ∼414 F g−1 (three-electrode system) and ∼197 F g−1 (two-electrode system) at 1 A g−1 current density in aqueous 1 M H2SO4 electrolyte. The porous activated carbon showed high performance in terms of electrochemical stability of 96 % in half cell configuration for 10,000 cycles, while the symmetric device showed 80 % cyclic stability for 5000 cycles in full cell configuration. Addition of redox active 0.01 M hydroquinone in the 1 M H2SO4 significantly improved the storage capacity to 540 C g−1 at current density of 3 A g−1 in two-electrode configuration and maintained 72 % of capacity for 5000 cycles. The redox-active symmetric supercapacitors show an energy density ∼26.9 W h kg−1 and power density ∼5527 W kg−1 and other related electrochemical properties.

Nitrogen/oxygen doped hierarchical porous carbon with adjustable pore structure for efficient adsorption, separation, and enhancement mechanism of methanol and acetone azeotropes: Experimental and theoretical study

The adsorption and separation of methanol and acetone are crucial for environmental protection and recycling. However, the separation of methanol and acetone azeotropes using carbon-based materials remains challenging, and the underlying mechanism is still unclear. Here, we propose the synthesis of porous carbon (NaOCs) using benzimidazole as a precursor and NaOH as an activator. With the increase of the proportion of NaOH and benzimidazole, the activation reaction was intensified, leading to the formation of numerous mesopores. NaOCs exhibit a maximum specific surface area (SBET) of 3084 m2/g, and has extremely high adsorption capacity of methanol (56.9 mmol/g at 13 kPa) and acetone (34.6 mmol/g at 18 kPa) at 25 °C. The results of experiments and molecular simulations indicate that the saturation adsorption capacity of methanol and acetone is determined by micropores and narrow mesopores at 25 °C, whereas the adsorption capacity at relatively low pressure is primary determined by ultramicropores and oxygen group. Furthermore, for methanol-acetone azeotropes separation, the acetone/methanol selectivity at low pressure depends on carbon surface polarity and ultramicropore, while methanol/acetone selectivity at high pressure depends on micropores of 1–2 nm. Our findings provide insights into the design and further development of adsorbents for VOCs adsorption and azeotrope separation applications.

The synthesis of porous carbon from coal liquefied residue and its electromagnetic wave absorption

The synthesis of porous carbon from coal liquefied residue and its electromagnetic wave absorption