High-performance Carbon Materials Research Articles

Multidimensional and hierarchical design of biomass-derived carbon nanofiber networks for efficient microwave absorption

Carbon materials have gained significant attention for their potential as highly efficient microwave absorbers. However, it remains a challenge to attain a perfect integration of thin thickness, wide frequency bandwidth, lightweight and strong absorption through structural design of carbon materials. Herein, we design multidimensional and hierarchical carbon nanofiber networks consisting of core-shell carbon nanofibers wrapped by hollow carbon nanoparticles, named CPDA@RCNFs. CPDA@RCNFs which are derived from cellulose and polydopamine (PDA) were prepared by electrostatic spinning, deacetylation, self-polymerization, and carbonization, successively. Thanks to the cooperation of three-dimensional conductive networks, core-shell/hollow/porous structures, as well as doped nitrogen and oxygen heteroatoms, CPDA@RCNFs exhibit excellent comprehensive microwave absorption performance. Specifically, an ultra-strong reflection loss value of −63.31 dB and a wide frequency bandwidth of 5.60 GHz (12.32–17.92 GHz) are achieved at a very thin thickness of 1.8 mm with an ultra-low filler loading of 5 wt%. This work provides a new insight into the structural design of advanced high-performance microwave absorption carbon materials.

Green synthesis of biomass-derived porous carbon with hierarchical pores and enhanced surface area for superior VOCs adsorption

The release of volatile organic compounds (VOCs) during the production, storage, and transportation of petroleum and its derivatives can be hazardous to human health and lead to secondary pollution. Addressing this challenge, this study introduces a sustainable and low-energy approach for synthesizing high-efficiency porous carbon materials, leveraging the abundant and renewable watermelon rinds as a carbon source. The carbonization and activation processes were optimized to minimize energy consumption while maximizing adsorptive performance. In this research, watermelon rinds were used as a source of carbon production, and melamine phosphate (FR-MP) was employed as a modifying agent. The FR-MP modified porous biomass-derived activated carbon (PWAC) was created by subjecting it to physical milling, carbonization, and activation. This approach not only utilized a waste biomass effectively but also reduced the overall carbon footprint of the production process. An examination of the effects of FR-MP dosage on the pore structure, surface chemical properties, and VOCs adsorption abilities of PWAC revealed that a higher FR-MP dosage resulted in a wider range of pore sizes within PWAC. The incorporation of FR-MP intensified the development of internal porosity and pore expansion in PWAC. Specifically, the optimized PWAC-0.3 exhibited a significant increase in specific surface area (3149 m²/g) and pore volume (1.76 cm³/g), enhancing adsorption capacities for acetone and n-hexane up to 1046 mg/g and 760 mg/g, respectively. Furthermore, the PWAC demonstrated exceptional recyclability, maintaining 97% of its original adsorption capacity after five cycles, underscoring its sustainable and economic viability. The highly advanced hierarchical ultra-meso-macroporous structure of PWAC significantly reduced the diffusion resistance of VOCs, guaranteeing swift mass transfer and desorption of VOCs. Consequently, the developed PWAC represents a novel, cost-effective, and environmentally-friendly approach for VOCs adsorption, aligning with the principles of green chemistry and low-energy consumption. This research not only provides a promising solution for VOCs mitigation but also highlights the potential of waste biomass in producing high-performance carbon materials.

Identifying the plateau sodium storage behavior of hard carbon through the spin state

Hard carbon has emerged as a promising anode material for rechargeable sodium-ion batteries, owing to its abundant precursor sources and remarkable reversible charge storage capacity. The key to achieving an extended sodium storage capacity lies in the plateau capacity largely associated with the closed-pore structure, yet a comprehensive understanding in this area remains incomplete. In our study, we utilized electron paramagnetic resonance (EPR) spectra to discern the spin state of unpaired electrons within hard carbon materials, enabling the identification of sodium storage plateau regions. Hard carbon anodes with plateau capacity predominantly exhibit delocalized spins, evident in the EPR spectrum by limited spin density and a linewidth exceeding 100 G. These spins originate from the extended aromatic structure within small-sized but curved nano-graphite and the closed-pore walls, which are crucial for plateau capacity. Conversely, hard carbon anodes exclusively possessing slope capacity are characterized by localized spins, presenting a typical narrow and intense Lorentzian EPR signal. These localized spins arise from the edge defects of the nano-graphite structure, serving as favourable sites for sodium adsorption. Our development of a methodology to discern hard carbon plateau capacity behavior based on EPR spectra presents a facile and rapid approach for advancing high-performance hard carbon materials.

A Ferricyanide Anion-Philic Interface Induced by Boron Species within Carbon Framework for Efficient Charge Storage in Supercapacitors.

Carbon materials with hierarchical porous structures hold great potential for redox electrolyte-enhanced supercapacitors. However, restricted by the intrinsic inert and nonpolar characteristics of carbon, the energy barrier of anchoring redox electrolytes on the pore walls is relatively high. As such, the redox process at the interface less occurs, and the rate of mass transfer is impaired, further leading to a poor electrochemical performance. Here, a ferricyanide anion-philic interface made of in situ inserted boron species into carbon rings is constructed for enhanced charge storage in supercapacitors. Profiting from the unique component-driven effects, the polar anchoring sites on the pore wall can be built to grasp the charged redox ferricyanide anion from the bulk electrolyte and promote the redox process; the dynamics process is fastened correspondingly. Especially, the boron atoms in BC2O and BCO2 units with higher positive natural bond orbital values in the carbon skeleton are pinpointed as intrinsic active sites to bind the negatively charged nitrogen atoms in the ferricyanide anion via electrostatic interaction, confirmed by density functional theoretical calculations. This will suppress the shuttle and diffusion effects of the ferricyanide anion from the surface of the electrode to the bulk electrolyte. Finally, the well-designed PC-3 with high content of BC2O and BCO2 units can reach 1099 F g-1 at 2 mV s-1, which is a more than 2-fold increase over boron-free units of carbon (428 F g-1). The work offers a novel version for designing high-performance carbon materials with unique yet reaction species-philic effects.

Direct carbonization of cellulose toward hydroxyl-rich porous carbons for pseudocapacitive energy storage

Designing carbon materials with specific oxygen-containing functional groups is very attractive for the precise decoration of carbon electrode materials and the basic understanding of specific charge storage mechanisms, which contributes to the further development of high-performance carbon materials for energy storage and conversion applications. In this contribution, a hydroxyl-rich micropore-dominated porous carbon material was obtained by direct carbonization of cellulose. The content of oxygen atoms in hydroxyl form in the obtained carbon is nearly 6 at.%. With the pyrolysis temperature changed, the macroscopic morphology, the specific surface area, surface functional groups, and graphitization degree of the carbon materials were changed strongly. Besides, the carbon material obtained with a carbonization temperature of 900 °C (C9) showed enhanced specific capacitance in sulfuric acid, sodium hydroxide, and sodium sulfate aqueous electrolytes, which mainly originates from the contribution of pseudocapacitance. The pseudocapacitance mainly depends on the presence of surface hydroxyl functional groups. Besides, the pseudocapacitance value of C9 material in neutral electrolytes (151.34 F g−1) is about twice that in acidic (75.9 F g−1) and alkaline (75.78 F g−1) electrolytes.

Soluble starch-derived porous carbon microspheres with interconnected and hierarchical structure by a low dosage KOH activation for ultrahigh rate supercapacitors

The developed porous structure and high density are essential to enhance the bulk performance of carbon-based supercapacitors. Nevertheless, it remains a significant challenge to optimize the balance between the porous structure and the density of carbon materials to realize superior gravimetric and areal electrochemical performance. The soluble starch-derived interconnected hierarchical porous carbon microspheres were prepared through a simple hydrothermal treatment succeeded by chemical activation with a low dosage of KOH. Due to the formation of interconnected spherical morphology, hierarchical porous structure, reasonable mesopore volume (0.33 cm3 g−1) and specific surface area (1162 m2 g−1), the prepared carbon microsphere has an ultrahigh capacitance of 394 F g−1 @ 1 A g−1 and a high capacitance retention of 62.7 % @ 80 A g−1. The assembled two-electrode device displays good cycle stability after 20,000 cycles and an ultra-high energy density of 11.6 Wh kg−1 @ 250 W kg−1. Moreover, the sample still exhibits a specific capacitance of 165 F g−1 @ 1 A g−1 at a high mass loading of 10 mg cm−2, resulting in a high areal capacitance of 1.65 F cm−2. The strategy proposed in this study, via a low-dose KOH activation process, provides the way for the synthesis of high-performance porous carbon materials.

Contrast variation method applied to structural evaluation of catalysts by X-ray small-angle scattering

In the process of developing carbon-supported metal catalysts, determining the catalyst particle-size distribution is an essential step, because this parameter is directly related to the catalytic activities. The particle-size distribution is most effectively determined by small-angle X-ray scattering (SAXS). When metal catalysts are supported by high-performance mesoporous carbon materials, however, their mesopores may lead to erroneous particle-size estimation if the sizes of the catalysts and mesopores are comparable. Here we propose a novel approach to particle-size determination by introducing contrast variation-SAXS (CV-SAXS). In CV-SAXS, a multi-component sample is immersed in an inert solvent with a density equal to that of one of the components, thereby rendering that particular component invisible to X-rays. We used a mixture of tetrabromoethane and dimethyl sulfoxide as a contrast-matching solvent for carbon. As a test sample, we prepared a mixture of a small amount of platinum (Pt) catalyst and a bulk of mesoporous carbon, and subjected it to SAXS measurement in the absence and presence of the solvent. In the absence of the solvent, the estimated Pt particle size was affected by the mesopores, but in the presence of the solvent, the Pt particle size was correctly estimated in spite of the low Pt content. The results demonstrate that the CV-SAXS technique is useful for correctly determining the particle-size distribution for low-Pt-content catalysts, for which demands are increasing to reduce the use of expensive Pt.

Preparation of green high-performance biomass-derived hard carbon materials from bamboo powder waste.

Efficient energy storage systems are crucial for the optimal utilization of renewable energy. Sodium-ion batteries (SIBs) are considered potential substitutes for next-generation low-cost energy storage systems due to the low cost and abundance of sodium resources. However, the industrialization of SIBs faces a great challenge in terms of the anode. Hard carbon could be a promising anode material due to its high capacity and low cost which originates from biomass. This study used pre-treatment and template carbonization methods to extract a hard carbon material from a large amount of discarded biomass in bamboo powder waste. This material has a good initial Coulombic efficiency of 78.6 % and good cycling stability when applied to sodium ion batteries.Typically, the optimal hard carbon material is used as the anode to prepare sodium ion battery prototypes to demonstrate their potential applications. The anode exhibited excellent sodium storage performance with a reversible capacity of 303 mAh ⋅ g-1 at 1 C rate and good cycling performance, retaining 92.0 % of its capacity after 100 cycles. These results demonstrate that BPPHC is a promising candidate for anode material in sodium-ion batteries. This work suggests that bamboo powder could be a low-cost anode material for SIBs.

π-Conjugated molecule mediated self-doped hierarchical porous carbons via self-stacking interaction for high-energy and ultra-stable zinc-ion hybrid capacitors

Understanding the self-stacking interactions in precursors can facilitate the preparation of high-performance carbon materials and promote the commercial application of zinc ion hybrid capacitors (ZIHCs). Here, a π-conjugated molecule mediated pyrolysis strategy is presented to prepare carbon materials. Taking intermolecular force simulation (reduced density gradient plots) as a guide, the relationship between the self-stacking interactions in π-conjugated molecules and the structural parameters of carbon materials can be extrapolated. The resultant self-doped hierarchical porous carbons (NHPCs) derived from 1, 8, 4, 5-naphthalenetetracarboxdiimide with suitable self-stacking interactions empower the highest specific surface areas (2038 m2/g) and surface opening macropores. The NHPCs-based ZIHCs deliver a high capacity of 220 mAh/g, a high energy density of 149.5 Wh kg−1 and a super-stable cycle lifespan with 93.2 % capacity retention after 200, 000 cycles. The excellent electrochemical performance roots in the superior hierarchical porous structure with surface opening macropores, which guarantees the structural stability of carbon cathodes upon repeated rounds. Meanwhile, the heteroatom doping further relieves the kinetics concern of Zn2+ uptake/removal to enhance O-Zn-N binding particularly at high discharge currents. Besides, the proton-assisted Zn2+ dual-ion storage mechanism plays an essential role in the energy storage process. This work demonstrates a facile synthesis method and advances the fundamental understanding of its dual-ion storage mechanism.

Preparation of high-performance nitrogen doped porous carbon from cork biomass by K2CO3 activation for adsorption of rhodamine B

Biomass waste, an attractive renewable carbon source, has great potential for carbon reduction. In recent years, high-performance porous carbon materials prepared from agricultural and forestry waste have demonstrated significant promise for applications in the field of dye wastewater purification. In this study, cork waste from Quercus variabilis was utilized as a raw material, melamine as a nitrogen source, and K2CO3 as a green activator to prepare nitrogen-doped porous cork activated carbon (NCAC) with a honeycomb structure. The results showed that NCAC-900, activated at 900 °C, exhibited a highly porous structure with an optimal specific surface area of 2051.35 m2/g and a pore volume of 1.18 cm3/g. To evaluate its adsorption performance towards rhodamine B (RhB), collaborative activation and post-treatment were employed to enhance the adsorption capacity of the dyes. NCAC-900 demonstrated excellent removal efficiency, with a theoretical maximum adsorption capacity of 2552.52 mg/g (at an adsorbent dosage of 0.2 g/L) in a 300 mg/L solution. Nitrogen doping effectively improved the adsorption capacity for RhB, fitting well to the quasi-secondary kinetic model (R2 = 0.9973–0.9999) and Langmuir isotherm (R2 = 0.7697–0.9523) for the adsorption kinetics and equilibrium data. A comparison with the existing literature also revealed that NCAC-900 possessed a remarkably fast adsorption rate of 12.82 mg/g/min. Moreover, the resorption efficiency of NCAC-900 for RhB reached approximately 66.78% after five consecutive adsorption-desorption cycles. Additionally, the obtained nitrogen-doped cork activated carbon exhibited impressive adsorption capabilities of anionic dye Congo red (CR, qm=1499.14 mg/g) and cationic dye methylene blue (MB, qm=571.54 mg/g). In conclusion, our work presented a promising method for preparing excellent NCAC as an efficient adsorbent for wastewater dyes, offering new ideas and theoretical foundations for the high-value utilization of cork materials and the development of cork activated carbon.

Solvothermal Synthesis and Pyrolysis Toward Heteroatom-Doped Carbon Microspheres for Zinc-Ion Hybrid Capacitors.

Heteroatom-doped porous carbon materials have investigated to promote the energy density of zinc-ion hybrid capacitors (ZICs). Yet, the quest for high-performance carbon materials or cathodes brings to light the question of which dopants facilitate fast energy storage kinetics and various types of pseudocapacitive reactions. Investigation of carbon materials with precise quantitative dopants as the key variable represents an effective appropriate approach to comprehending the intricate role of dopants in energy storage areas. Here, a straightforward solvothermal strategy is demonstrated for a variety of pristine and iron-incorporated polymer microspheres, used as precursors for durable spherical carbons intended for cathode applications in ZICs. The strategy effectively governs the incorporation of dopants within the carbon materials, whilewhile maintaining consistent morphology, microtexture, and pore structure across different carbon variations. The synergistic effect of various dopants enhance the pseudocapacitance and facilitate the ion storage process. In consequence, the optimal cathode delivers considerable capacity (178.8mAhg-1 at 0.5Ag-1), good energy density (120.2Whkg-1 at 336Wkg-1), and excellent cycling stability (101.5% capacity retention at 35000 cycles). The demonstration showcases a viable method for crafting carbon materials with precise dopants to accommodate the zinc anode, thus enabling high-capacity and high-energy ZICs.

Synergy of structural engineering and dual-heteroatoms co-doping engineering boosting porous carbon toward efficient capacitive deionization

Carbon materials have drawn increasing attention as promising electrode materials for capacitive deionization (CDI) on account of their excellent conductivity and high specific surface area. Nevertheless, the practical application of conventional carbon materials has been significantly impacted by the limited desalination capacity and the slow desalination rates. Herein, a series of hierarchical porous nitrogen and sulfur co-doped carbons (PNSC-X, X = 2.5, 5, and 7.5) were successfully prepared by combining the salt template method with the dual-heteroatoms co-doping method. Benefiting from the suitable degree of graphitization, the unique hierarchical porous structure (micropores-mesopores-macropores) and the synergistic effect between the nitrogen/sulfur (N/S) dual-dopant, the optimized electrode (PNSC-5) demonstrates an abundance of active sites and rapid reaction kinetics, which are conducive to remarkably improving the CDI performance. In consequence, as a promising electrode material for CDI, the PNSC-5 exhibits excellent desalination performance (39 mg g−1 under 1.2 V), outstanding salt adsorption rate (3.23 mg g−1 min−1) and eminent stability. The CDI device with PNSC-5 as electrode shows low energy consumption and high charging efficiency during the cycle test. Furthermore, the corresponding desalination mechanism is systematically expounded by various characterization methods. This work provides a new inspiration for exploiting high-performance carbon materials for efficient electrochemical desalination.

Synthesis of Low-Cost and High-Performance Dual-Atom Doped Carbon-Based Materials with a Simple Green Route as Anodes for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) are promising alternatives to replace lithium-ion batteries as future energy storage batteries because of their abundant sodium resources, low cost, and high charging efficiency. In order to match the high energy capacity and density, designing an atomically doped carbonous material as the anode is presently one of the important strategies to commercialize SIBs. In this work, we report the preparation of high-performance dual-atom-doped carbon (C) materials using low-cost corn starch and thiourea (CH4N2S) as the precursors. The electronegativity and radii of the doped atoms and C are different, which can vary the embedding properties of sodium ions (Na+) into/on C. As sulfur (S) can effectively expand the layer spacing, it provides more channels for embedding and de-embedding Na+. The synergistic effect of N and S co-doping can remarkably boost the performance of SIBs. The capacity is preserved at 400 mAh g -1 after 200 cycles at 500 mA g-1; more notably, the initial Coulombic efficiency is 81%. Even at a high rate of high current of 10 A g-1, the cell capacity can still reach 170 mAh g-1. More importantly, after 3000 cycles at 1 A g-1, the capacity decay is less than 0.003% per cycle, which demonstrates its excellent electrochemical performance. These results indicate that high-performance carbon materials can be prepared using low-cost corn starch and thiourea.

Production of hierarchical porous bio‑carbon based on deep eutectic solvent fractionated lignin nanoparticles for high-performance supercapacitor

Owing to the low synthetic cost, low toxicity for most types and outstanding lignin solubility, deep eutectic solvents (DESs) have been recently exploited in fractionation of lignocellulosic biomass. Unfortunately, the DES-fractionated lignin, as another major product, was usually ignored and disposed improperly. Accordingly, the present study employed DES (choline chloride:lactic acid) to fractionate natural biomass for producing highly dispersed lignin nanoparticles. The obtained nano-lignin was utilized to prepare electrode materials for supercapacitors for the first time, and a higher specific capacitance than those prepared from conventional lignin was acquired. The results demonstrated that the lignin fractionation rate could be promoted via extending treatment time at low temperatures, whereas the DES to biomass mass ratio might be the lignin dissolution-limiting factor at high temperature. Uniform lignin nanoclusters could be obtained after DES fractionation, and increasing fractionation temperature was beneficial for preparing nano-lignin in DES. The cleavages of lignin-carbohydrate complexes and lignin subunits might account for the formation mechanism of lignin oligomers. Meanwhile, the aggregation of monolignols could contribute to the growth of lignin nanoparticles. The one-step KOH activation could induce hierarchical pores in lignin fractionated from moderate residence time, whereas two-step method was advisable for more aggregated DES-lignin. Based on the directly activated DES-lignin with a high surface area of 3577.3 m2 g−1, the prepared supercapacitor exhibited a superior specific capacitance of 248.8 F g−1. This study aimed to provide a novel method for producing high-performance energy storage carbon materials based on DES fractionated lignin from lignocellulose.

Facile Synthesis of a Highly Value-Added High-Performance Carbon Material from Waste Masks for Advanced Supercapacitors

Facile Synthesis of a Highly Value-Added High-Performance Carbon Material from Waste Masks for Advanced Supercapacitors

Molecular composition of direct coal liquefaction products obtained from the Shenhua industrial plant

The China Shenhua company has built and operated the only large industrial direct coal liquefaction (DCL) plant in the world for 15 years, with an oil product capacity of one million tons per year. However, there is insufficient information on the chemical composition of its products. In this study, the liquefaction product, including the distillate oil and the vacuum residue, as well as the circulating solvent were characterized by gas chromatography – mass spectrometry (GC–MS) and high-resolution mass spectrometry. The liquefaction oil has lower H/C ratio and higher oxygen and nitrogen contents compared to hydrogenation products derived from petroleum. The major component of the liquefaction oil is middle-temperature distillate, which is approximately 70 wt% concentrated in the range of 200–350 °C. Pyrene and perhydropyrene are the most abundant compounds in the liquefaction oil. Hydrocarbons with 1–4 aromatic rings were detected in the liquefaction oil, with skeletons of benzene, biphenyl, naphthalene, fluorene, phenanthrene, pyrene, etc.. Various partially hydrogenated and perhydrogenated aromatic compounds were identified in the oils and they even constitute the major component of the circulating solvent. 2,3-Dihydro-1H-phenalene was also found in high-relative abundance in the oils and has potential to be used as a marker for coal liquefaction produced through hydrogenation processes. Partially hydrogenated polycyclic aromatics exhibit higher dehydrogenation activity compared to tetralin. The organic component in the vacuum residue account for around 60 wt%, with toluene insoluble matter accounting for more than one third. The toluene soluble fraction has an H/C ratio of 0.82 and is mainly composed of aromatic with 4–8 rings. The molecular size and condensation degree of the residue are much higher than those of other fossil fuel-derived aromatic-rich substances. Further studies are necessary to evaluate whether aromatic hydrocarbons with such a high condensation degree are suitable for producing high-performance carbon materials.

Hierarchically Porous Carbon Nanosheets from One-Step Carbonization of Zinc Gluconate for High-Performance Supercapacitors.

Supercapacitors, with high energy density, rapid charge-discharge capabilities, and long cycling ability, have gained favor among many researchers. However, the universality of high-performance carbon-based electrodes is often constrained by their complex fabrication methods. In this study, the common industrial materials, zinc gluconate and ammonium chloride, are uniformly mixed and subjected to a one-step carbonization strategy to prepare three-dimensional hierarchical porous carbon materials with high specific surface area and suitable nitrogen doping. The results show that a specific capacitance of 221 F g-1 is achieved at a current density of 1 A g-1. The assembled symmetrical supercapacitor achieves a high energy density of 17 Wh kg-1, and after 50,000 cycles at a current density of 50 A g-1, it retains 82% of its initial capacitance. Moreover, the operating voltage window of the symmetrical device can be easily expanded to 2.5 V when using Et4NBF4 as the electrolyte, resulting in a maximum energy density of up to 153 Wh kg-1, and retaining 85.03% of the initial specific capacitance after 10,000 cycles. This method, using common industrial materials as raw materials, provides ideas for the simple preparation of high-performance carbon materials and also provides a promising method for the large-scale production of highly porous carbons.

Nitrogen doped soap-nut seeds derived hard carbon as an efficient anode material for Na-ion batteries

Biomass-derived hard carbon materials have received promising research interest because of their low cost, high abundance, and renewability. In the present study, high-performance hard carbon material is prepared from soap-nut seeds (SNS-0) using a simple pyrolysis process. Further, N (nitrogen) heteroatoms are introduced into the hard carbon matrix to modify its structure using melamine as the N source. High-resolution transmission electron microscopy images reveal the development of the localized graphite-like structure after the introduction of N atoms in the hard carbon, which are found to be beneficial for the storage and transport of the larger Na ions in the battery. The optimal doping of N (1:1 wt. ratio, SNS-1) in the hard carbon has improved the storage performance of the SNS-0 electrode, providing a reversible capacity of 353 mA h g−1 at a current density of 25 mA g−1. The improved electrochemical characteristics of the SNS-1 electrode over the other compositions are associated with its lesser specific surface area (282.87 m2 g−1) and higher interlayer spacing (0.38 nm). The present study not only reveals the useful conversion of a biomass waste, soap-nut seeds, into a low-cost and sustainable eco-friendly hard carbon material but also its potential use as an efficient anode for Na-ion battery applications.

Investigation on the mechanism of structural reconstruction of biochars derived from lignin and cellulose during graphitization under high temperature

The structural reconstruction mechanism of lignin and cellulose-derived biochars during direct graphitization under ultra-high temperatures was intensively investigated. It was demonstrated that cellulose-derived char was almost composed of carbon microcrystallites, whereas lignin-derived char reserved some of its skeleton structures, and such structural difference played a vital role in the morphology of formed graphitic layers. The results illustrated that the graphitized lignin-derived sample under 2800 ℃ had graphitic degree of 89.53%, interlayer spacing of 0.3363 nm and electronic conductivity of 104.6 S cm−1, while cellulose-derived sample had graphitic degree of 76.74%, layer distance of 0.3374 nm, and electronic conductivity of only 48.8 S cm−1. Combined with the results of structural analysis of the chars derived from lignin and cellulose, it was inferred that the stable and aromatic ring containing skeleton structure in lignin was beneficial to the ring-enlarging reconstruction and the formation of large areas of continuous graphitic layers during graphitizing process, leading to high electronic conductivity. Meanwhile, the interwoven microcrystallites in cellulose-derived char strongly restricted the expanding of continuous lamellar graphitic areas even at such ultra-high temperature, causing the formation of turbostratic structure with numerous structural defects as well, and finally resulting in relatively lower electronic conductivity. This work is expected to provide theoretical guidance for preparing high-performance functional carbon materials from lignocellulosic biomass.Graphical

Biomass-derived functional carbon material for CO2 adsorption and electrochemical CO2 reduction reaction

CO2 adsorption and electrocatalytic CO2 reduction (CO2RR) have been considered a promising path to realize CO2 emission reduction and simultaneously producing value-added chemicals. However, the high price and unsatisfactory performance of adsorbent or electrocatalyst materials have limited their application. Our group focuses on developing high-performance carbon materials derived from biomass for efficient CO2 adsorption and CO2RR. The effect of pyrolytic parameter and modifying agents was systematically studied to figure out the formation mechanism of biomass-derived carbon material. Furthermore, the mechanism CO2 adsorption and CO2RR are explored to determine required physicochemical properties of these carbon materials. Notably, in order to precisely introduce the desired pore structure and functional groups onto material, the idea of combining adjustable and modifiable metal-organic frameworks (MOFs) with environmentally friendly and stable biomass was proposed. The challenge in the application of biomass-derived functional carbon material is clarified. Through researchers are constantly dedicated to this field of research, it is believed that biomass-derived carbon material will find their unique positions in helping achieving carbon neutral.