Cellulose Carbon Research Articles

Rational Design of Nanostructured Metal/C Interface in 3D Self‐Supporting Cellulose Carbon Aerogel Facilitating High‐Performance Li‐CO2 Batteries

AbstractThe sluggish kinetics of CO2 reduction and evolution reaction (CRR and CER) on the Li–CO2 battery cathode seriously hindered its practical application. Rational design of the Ru/C interface is expected to simultaneously decrease the free energy barrier of intermediate species and create a favorable electronic structure, effectively promoting the catalytic reaction kinetics of the CRR and CER. Herein, a 3D self‐supporting cellulose carbon aerogel (CCA) with well‐defined Ru/C interfaces (Ru@CCA) is synthesized as an advanced CO2‐breathing cathode for Li–CO2 batteries. The results show that the energy efficiency significantly improves to 80% with a high discharge capacity of 10.71 mA h cm−2 at 20 µA cm−2, and excellent cyclic stability of 421 cycles at 100 µA cm−2. These outstanding performances are highly competitive compared with state‐of‐art Li–CO2 cathodes. In addition, the unique interface design strategy is applied to other non‐noble metal@CCA cathodes, which confirms the advantages of constructing nanostructure metal/C interfaces for improving the kinetics of CRR and CER. This fundamental understanding of the structure–performance relationship provides new inspiration for designing highly efficient cathode catalysts for Li–CO2 batteries.

Co-hydrothermal carbonization of cellulose, hemicellulose, and protein with aqueous phase recirculation: Insight into the reaction mechanisms on hydrochar formation

Co-hydrothermal carbonization (Co-HTC) coupled with aqueous phase (AP) recirculation has huge potential to improve hydrochar production. In this study, three model compounds, namely wheat straw cellulose (cellulose, Ce), xylan (hemicellulose, He), and soya-protein (protein, Pr), were processed by HTC individually or Co-HTC in combination, with or without AP recirculation. Hydrochar formation behavior was investigated through analysis of hydrochar and AP by elemental analysis, X-ray photoelectron spectroscopy (XPS), Pyrolyzer-gas chromatography-mass spectrometry (Py-GC-MS), GC-MS, and a series of other characterizations. Elemental compositions reveal that both Co-HTC and AP recirculation promoted hydrochar formation and reduction of oxygen in hydrochar, and the combination promoted these effects. Furthermore, XPS and Py-GC-MS results show that the building blocks of hydrochar were oxygenated compounds from Ce and He such as furans and furfurals, and nitrogen-containing compounds from Pr such as amino acids and N-heterocycles. Subsequently, hydrochar formation mechanisms were proposed by results from GC-MS analysis of AP and the above observations. The major mechanisms account for enhanced hydrochar formation during Co-HTC with AP recirculation were Maillard reaction occurred between amino acids and saccharides, catalytical effects (mainly on Maillard reaction) from acids in the recycling AP, and the repolymerization or condensation of accumulated compounds in AP.

Advances in understanding the humins: Formation , prevention and application

The formation of dark-colored solids, as known as humins, was observed during acid-catalyzed dehydration of certain biomass platform molecules like fructose, glucose and 5-hydroxymethylfurfural (HMF). Humins structures were found to be precipitated as microspheres in the liquid phase and/or on the surfaces of solid catalyst and reactor walls. Humins formation begins with random and uncontrollable condensation of key intermediate molecules, namely, glucose, HMF, 1,2,4-Trihydroxybenzene (TB), 2,5-dioxo-6-hydroxyhexanal (DHH), etc. Further, mechanism network of humins formation also contains polymerization of soluble oligomers, growth of primary particles, physical absorption to soluble molecules and aggregation of particle groups. Humins formation retards the economy, safety and efficiency of cellulosic carbon conversion including wasting the substrates, blocking the reactor, causing deactivation of catalyst and absorbing the high-value molecules products. This necessitates the systematic elucidation of humins, including its formation mechanism network, characterization techniques and high-value utilization. This review organized significant studies of humins formation, including (i) background information of humins during different conversion process, (ii) different analytical techniques for humins characterization, (iii) the properties and formation mechanism of humins, (iv) prevention methods of humins formation and (v) exploration of high-value humins utilization.

Top-down strategy for bamboo lignocellulose-derived carbon heterostructure with enhanced electromagnetic wave dissipation

Biomass-derived residue carbonization has been an important issue for “carbon fixation” and “zero emission”, and the carbonized products have multiple application potentials. However, there have been no specific research to study the differences in macro- and micro-morphology, electrical properties and many other aspects of the products obtained from carbonization of pure cellulose, pure lignin or their complex, lignocellulose. In this work, lignocellulose with cellulose to lignin mass ratio of 10:1 is obtained using p -toluenesulfonic acid hydrolysis followed by homogenization process at a controlled condition. Then, carbon heterostructure with fibers and sheets (CH-10) are obtained by pyrolysis at 1500 °C. Detailed results imply that the fiber-like carbon structure possesses high crystallinity and low defect density, coming from carbonization of the cellulose content in lignocellulose (LC) nanofibers. Correspondingly, the graphite-like carbon sheet with high defect density and low crystallinity comes from carbonization of the lignin content in LCs. Further investigation indicates CH-10 possesses enhanced polarization and moderate impedance matching which makes it an ideal candidate for electromagnetic wave (EMW) absorption. CH-10 exhibits an excellent EMW absorption performance with a minimum RL value of −50.05 dB and a broadest absorption bandwidth of 4.16 GHz at a coating thickness as thin as 1.3 mm.

Synthesis of Polyanionic Cellulose Carbamates by Homogeneous Aminolysis in an Ionic Liquid/DMF Medium.

Polyanionic cellulose carbamates were synthesized by rapid and efficient homogeneous aminolysis of cellulose carbonate half-esters in an ionic liquid/DMF medium. Cellulose bis-2,3-O-(3,5-dimethylphenyl carbamate), as a model compound, reacted with different chloroformates to cellulose carbonates. These intermediates were subjected to aminolysis, for which both the reactivity of different chloroformates towards C6-OH and the reactivity/suitability of the respective carbonate half-ester in the aminolysis were comprehensively studied. Phenyl chloroformate and 4-chlorophenyl chloroformate readily reacted with C6-OH of the model cellulose derivative, while 4-nitrophenyl chloroformate did not. The intermediate 4-chlorophenyl carbonate derivative with the highest DS (1.05) was then used to evaluate different aminolysis pathways, applying three different amines (propargyl amine, β-alanine, and taurine) as reactants. The latter two zwitterionic compounds are only sparingly soluble in pure DMF as the typical reaction medium for aminolysis; therefore, several alternative procedures were suggested, carefully evaluated, and critically compared. Solubility problems with β-alanine and taurine were overcome by the binary solvent system DMF/[EMIM]OAc (1:1, v/v), which was shown to be a promising medium for rapid and efficient homogeneous aminolysis and for the preparation of the corresponding cellulose carbamate derivatives or other compounds that are not accessible by conventional isocyanate chemistry. The zwitterionic cellulose carbamate derivatives presented in this work could be promising chiral cation exchangers for HPLC enantiomer separations.

Persian Walnut (Juglans regia L.) Bud Dormancy Dynamics in Northern Patagonia, Argentina.

Temperate deciduous fruit trees survive winter temperatures by entering a dormant phase in their aerial meristematic organs. Release from bud dormancy occurs after chill requirements (CR) have been satisfied, whereas bud burst/flowering follows heat requirement (HR) fulfillment. The physiological basis behind these metrics remains elusive. In this study, we are presenting the first multidisciplinary dormancy progression analysis in northern Patagonia, linking (1) forcing/field phenology, (2) bud anatomical development, and (3) soluble sugar (sucrose, glucose, and fructose) dynamics in Juglans regia L. CR and HR were determined for ‘Chandler’ and ‘Franquette,’ two walnut cultivars with markedly different CR, in artificial chill/forced heat trials (three seasons) and in-field chill/forced heat tests (five seasons) using excised twigs either with or without apical buds (non-decapitated and decapitated). The soluble sugar dynamics of ‘Chandler’ (high-performance liquid chromatography) and the anatomical changes of the buds (light microscopy) of the two cultivars were analyzed during endo-ecodormancy progression in one and two seasons, respectively. The CR defined by artificial chill tests proved to be an overestimation compared to the field determinations. Moreover, HR was the main driver in the phenology dynamics, as expected for a high-chill region. ‘Chandler’ showed an average of 10.3 field chill portions (CP) and 2,163 Growing Degree Hours (GDH°C) less than ‘Franquette’ for dormancy release and bud burst, respectively. These results were consistent with the transition of the shoot apex from the vegetative to the reproductive phase and the soluble sugar profile. The decrease in sucrose between 15 and 30 days after CR fulfillment could be a reliable biological marker for endodormancy release in walnut, while the increase in fructose and glucose is likely an osmolyte and cellulosic carbon source in pre-sprouting. In addition, we discuss the effect of paradormancy thanks to our apical bud experiment (with or without). Our results improve the current understanding of endo-ecodormancy progression in walnut and provide insightful results for walnut production (i.e., cultivation practices such as pruning) as well as for further application in dormancy modeling, to infer the ideotypes that should be bred for future climate conditions.

Carbon Dioxide Mediated Cellulose Dissolution and Derivatization to Cellulose Carbonates in a Low-pressure System

An effective switchable solvent system using carbon dioxide (CO2) and 2-tert-butyl-1,1,3,3-tetramethylguanidine (BTMG) for cellulose dissolution and derivatization was developed. High concentration cellulose solution (up to 10 wt%) could be achieved by dissolving microcrystalline cellulose rapidly, within 5 min, into DMSO in presence of BTMG and 1 atm CO2 at room temperature. The cellulose-carbonate anion intermediate was characterized by 1H and 13C NMR spectroscopies, emphasizing the generation of cellulose carbonate anions and protonated BTMG. Addition of organochlorides into the cellulose solution triggers a nucleophilic substitution with cellulose-carbonate anions, producing various cellulose benzyl carbonates and a cellulose-carbonate-ester with degree of substitution (DS) up to 1.83 at 1 atm CO2 pressure and room temperature. The activation energy (Ea) and Gibbs free energy change (ΔG) of CO2-mediated dissolution and nucleophilic substitution were calculated by density functional theory. The results showed that the nucleophilic substitution is the rate-limiting step.

Pyrolysis of fast growing wood Macaranga gigantea: Product characterisation and kinetic study

Fast-growing wood Macaranga gigantea has been pyrolyzed and its pyrolysis products have been characterized and their formation kinetics studied. Pyrolysis of M. gigantea wood was carried out by varying the temperature and time of pyrolysis to determine the effect of these two parameters on product yields and product characteristics. In general, an increase in pyrolysis temperature and time increased the yield of liquid and gas products, the concentration of cellulose, hemicellulose and lignin-derived compounds, but decreased the biochar yield. The organic phase liquid pyrolysis products mainly contained phenolic compounds and their derivatives, eugenols, furans, aldehydes and ketones. Fourier-transform infrared spectroscopy and pyrolysis–gas chromatography–mass spectrometry analyses of biochar showed that thermal decomposition of M. gigantea required temperatures higher than 300 °C to optimize thermal decomposition and carbonization of lignin, cellulose and hemicellulose. The concentration of phenols and benzenediols in biochar decreased with an increase in pyrolysis temperature. M. gigantea pyrolysis kinetics studies showed that wood pyrolysis occurred through four main stages with activation energy (Eα) values, based on calculations by the Friedman and Kissinger-Akahira-Sunose methods, of 28.1–99.0 kJ/mol and 35.6–104.9 kJ/mol, respectively. The spectra produced by thermogravimetric analyzer coupled with a Fourier-transform infrared spectroscopy showed that H2O and CO2 were produced during pyrolysis and the volatile compounds produced were predominantly phenolic compounds, in accord with characterization results of the liquid products by gas chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy.

Hydrothermal carbonization of cellulose in aqueous phase of bio-oil: The significant impacts on properties of hydrochar

Aqueous phase of bio-oil (APBO) is a major fraction of bio-oil deriving from pyrolysis of biomass. APBO mostly contains water, carboxylic acids and different kinds of organics, which can afford a potential reactive medium for hydrothermal carbonization (HTC) of biomass. In this study, the HTC of cellulose in APBO was conducted, aiming to probe the effects of the APBO organics on the properties of the hydrochar. The results showed that the organics such as sugars, sugar-derivatives and phenolics in APBO could adsorb on the surface of cellulose and suppress the hydrolysis at lower temperature (i.e. 180 °C), while they could cross-polymerize with cellulose derivatives at higher temperatures (i.e. 220 or 260 °C). Compared with the hydrochar obtained in water, the APBO remarkably enhanced hydrochar yield by 11.3% and resulted in the abundant formation of aliphatic structures, making the hydrochar carbon and hydrogen-rich but with a lower thermal stability. In addition, the involvement of the APBO organics within the cross-polymerization interfered with the nucleation of the sugars/furans and inhibited the formation of the spheres with a hydrophilic shell and a hydrophobic core, resulting in the formation of an irregularly shaped hydrochar. Such a process also made the hydrochar rather hydrophobic, while the combustion performance was highly improved, exhibiting a lower ignition temperature (170 °C in APBO vs 306 °C in water).

Simultaneous Carbonization and Sulfonation of Microcrystalline Cellulose to Obtain Solid Acid Catalyst and Carbon Quantum Dots

Simultaneous Carbonization and Sulfonation of Microcrystalline Cellulose to Obtain Solid Acid Catalyst and Carbon Quantum Dots

Helically aligned fused carbon hollow nanospheres with chiral discrimination ability.

While the functions of carbon materials with precisely controlled nanostructures have been reported in many studies, their chiral discriminating abilities have not been reported yet. Herein, chiral discrimination is achieved using helical carbon materials devoid of chiral attachments. A Fe3O4 nanoparticle template with ethyl cellulose (carbon source) is self-assembled on dispersed multiwalled carbon nanotubes (MWCNTs) fixed in a lamellar structure, with helical nanoparticle alignment induced by the addition of a binaphthyl derivative. Carbonization followed by template removal produces helically aligned fused carbon hollow nanospheres (CHNSs) with no chiral molecules left. Helicity is confirmed using vacuum-ultraviolet circular dichroism spectroscopy. Chiral discrimination, as revealed by the electrochemical reactions of binaphthol and a chiral ferrocene derivative in aqueous and nonaqueous electrolytes, respectively, is attributable to the chiral space formed between the CHNS and MWCNT surfaces.

Co-Hydrothermal Carbonization of Cellulose, Hemicellulose, and Protein with Aqueous Phase Recirculation: Insight into the Reaction Mechanisms on Hydrochar Formation

Co-Hydrothermal Carbonization of Cellulose, Hemicellulose, and Protein with Aqueous Phase Recirculation: Insight into the Reaction Mechanisms on Hydrochar Formation

Residual peel of pitaya fruit (Hylocereus undatus) as a precursor to obtaining an efficient carbon-based adsorbent for the removal of metanil yellow dye from water

The pitaya peel (Hylocereus undatus) was carbonized in the presence of ZnCl2 to obtain a carbon-based adsorbent to remove the Metanil Yellow dye (MY) from colored waters. The characterization techniques confirmed that the material had morphological changes with the appearance of new irregularities and cavities. Besides, the alternative adsorbent was formed mainly by carbon and functional groups characteristic of lignin and cellulose. Isothermal and kinetic studies were carried out at the natural pH of the solution at a dosage of 0.4 g L−1. The Langmuir model demonstrated the best adjustment of the equilibrium isotherms of the system, reaching the maximum adsorption capacity of 144.07 mg g−1 at 298 K. The thermodynamic behavior indicated that it is a spontaneous and favorable process of an exothermic nature (ΔH0=−34.02 kJ mol−1), consistent with a mechanism involving electrostatic interactions. The MY concentration influenced the kinetic. The homogeneous surface diffusion model (HSDM) showed good statistical adjustment to the kinetic values, showing a slight increase in the diffusivity coefficient from 2.4 × 10−9 to 4.5 × 10−9 cm2 s−1 with the increased MY concentration. The material application in a mixture containing several dyes and salts in the circumstances close to the real ones showed removal of 82.5%. The adsorbent could be regenerated and used 12 times. Therefore, it can be concluded that the pitaya fruit residual biomass can be used as a precursor for preparing carbon-based adsorbents. The adsorbent, in turn, is a promising alternative in the treatment of MY dye and mixtures of organic molecules.

Aging Status Prediction of Oil Impregnated Insulating Kraft Paper Using GLCM Based Textural Features

This paper presents the prediction of aging state of oil impregnated insulating Kraft paper using textural properties. Under conditions of prolonged thermal stress, the insulating capacity of Kraft paper decreases due to carbonization and degradation of cellulose. To analyze these effects, a new accelerated aging kit is developed for the experiments. Four groups of samples are collected, and the morphology is examined. Texture feature is extracted for the samples using normalization and Gray-Level Co-occurrence Matrix (GLCM). Supervised (Support Vector Machine (SVM)) and unsupervised (K-means) machine intelligence methods are trained to classify images based on the feature. In addition, new samples are checked for feasibility of the prediction of aging state. The calculated training accuracy of SVM is 92.67%, and for k-means is 95.0%, on the other hand, the testing accuracy of SVM is 91.0%, and for k-means is 92.6%. Therefore, this machine intelligence-based methodology using image features is effective in classifying the aging state of the Kraft Insulating Paper.

Effects of hydrothermal carbonization on products from fast pyrolysis of cellulose

In the first step of this study, the hydrothermal carbonization (HTC) of cellulose was performed at 225 and 250 °C for 4, 8 and 12 h. The effect of temperature and residence time on hydrochar (HC) yields and characteristics was investigated, and the highest hydrochar yield had a heating value of 21.06 MJ/kg. In the second step, cellulose and hydrochar-derived cellulose was subjected to fast online pyrolysis at 500, 600 and 700 °C, using a pyrolysis-gas chromatography-mass spectrometry system. The HTC process significantly affected the pyrolysis products. The major decomposition product resulting from the fast pyrolysis of cellulose was levoglucosan, but at all tested temperatures, 2-methylfuran was the major product from hydrochars. Increasing the pyrolysis temperature caused a decrease in the relative yield of 2-methylfuran. Another prominent compound observed in pyrolyzates was 2,5-dimethylfuran. The relative yields of these two compounds decreased when the residence time of the HTC process was increased. The highest 2-methylfuran selectivity was 67.4%, while the highest 2,5-dimethylfuran selectivity among the furanic compounds was 24.0%. This study demonstrated that, by combining HTC and pyrolysis processes, fine chemicals can be produced from cellulose.

Direct Evidence for Reaction between Cellulose and CO2 from Nuclear Magnetic Resonance

The direct reaction between carbohydrates and CO2 has recently attracted attention in the context of cellulose dissolution and derivatization as well as carbon capture applications. We have directly demonstrated the formation of cellulose carbonate upon the introduction of CO2 into a non-aqueous cellulose solution by nuclear magnetic resonance spectroscopy. Comparison of the observed spectra with accurate electronic structure calculations of the changes in chemical shifts upon reaction allowed us to confirm the expectation that CO2 reacts with the hydroxyl group on carbon 6 of the cellulose but not exclusively this hydroxyl group. We found good agreement between predicted and measured chemical shifts using a simple computational method.

Waste to wealth: SnO2 nanoparticles anchoring jute fiber cellulose carbon substrates as anode materials for high-performance lithium-ion batteries

Waste to wealth: SnO2 nanoparticles anchoring jute fiber cellulose carbon substrates as anode materials for high-performance lithium-ion batteries

Spring arctic oscillation as a trigger of summer drought in Siberian subarctic over the past 1494\xa0years

Rapid changes in the hydrological and temperature regimes over the past decades at the northern latitudes enhance significantly permafrost degradation accelerating carbon release, increase the frequency of drought events and extensive wildfires. However, the mechanisms and dynamics driving drought events and their influence on Siberian forests are currently the subject of numerous research activities. Newly developed and annually resolved stable carbon and oxygen isotope chronologies of larch tree-ring cellulose (δ13Ccell and δ18Ocell) for the period 516–2009 CE allowed the reconstruction of July precipitation and Arctic Oscillation (AO) in May, respectively. Unprecedented drought events occurred towards twentieth–twenty-first centuries as indicated by the July precipitation reconstruction. Positive AO phases in May were most pronounced during the second part of the first millennium, but also increased in frequency in the modern period of the twentieth–twenty-first centuries. Negative AO phases are associated with cold anomalies and show a remarkable decrease in the nineteenth century caused by a series of major volcanic eruptions. Our findings help explaining the increased frequency of Siberian forest fires over the past decades in Central Siberia consistent with a reduction of summer precipitation, triggered by a positive phase of the Arctic Oscillation in May.

Physiological responses of Douglas-fir to climate and forest disturbances as detected by cellulosic carbon and oxygen isotope ratios.

Swiss needle cast (SNC), caused by a fungal pathogen, Nothophaeocryptopus gaeumannii, is a major forest disease of Douglas-fir (Pseudotsuga menziesii) stands of the Pacific Northwest (PNW). There is mounting concern that the current SNC epidemic occurring in Oregon and Washington will continue to increase in severity, frequency and spatial extent with future warming. Nothophaeocryptopus gaeumannii occurs wherever its host is found, but very little is known about the history and spatial distribution of SNC and its effects on growth and physiological processes of mature and old-growth forests within the Douglas-fir region of the PNW. Our findings show that stem growth and physiological responses of infected Douglas-fir to climate and SNC were different between sites, growth periods and disease severity based on cellulosic stable carbon and oxygen isotope ratios and ring width data in tree rings. At a coastal Oregon site within the SNC impact zone, variations in stem growth and Δ13C were primarily influenced by disproportional reductions in stomatal conductance (gs) and assimilation (A) caused by a loss of functioning stomates through early needle abscission and stomatal occlusion by pseudothecia of N. gaeumannii. At the less severely infected inland sites on the west slopes of Oregon's Cascade Range, stem growth correlated negatively with δ18O and positively with Δ13C, indicating that gs decreased in response to high evaporative demand with a concomitant reduction in A. Current- and previous-years summer vapor pressure deficit was the principal seasonal climatic variable affecting radial stem growth and the dual stable isotope ratios at all sites. Our results indicate that rising temperatures since the mid-1970s has strongly affected Douglas-fir growth in the PNW directly by a physiological response to higher evaporative demand during the annual summer drought and indirectly by a major SNC epidemic that is expanding regionally to higher latitudes and higher elevations.

Nitrogen and Oxygen Codoped Carbon Anode Fabricated Facilely from Polyaniline Coated Cellulose Nanocrystals for High-Performance Li-Ion Batteries

A facile approach was developed to fabricate nitrogen/oxygen (N/O) codoped carbon anodes by direct carbonization of cellulose nanocrystal/polyaniline (CNC/PANi) nanocomposites which were prepared by in situ growth of PANi onto CNCs. The carbonized CNC/PANi (c-CNC/PANi) anode delivered a high reversible capacity of 470 mAh g–1 at 200 mA g–1 over 100 cycles, which was almost two times higher than those for c-CNC. Moreover, it presented a better rate performance and higher Li-ion diffusion coefficient than c-CNC and c-PANi anodes. The c-CNC/PANi anode also exhibited a distinguished cycling stability with high Coulombic efficiency around 100% at a high current density of 1000 mA g–1 even after 2000 cycles. The significant improvement in the electrochemical performance should be attributed to the larger specific area and uniform N/O dual heteroatoms codoping which can provide sufficient active sites for Li ions storage and induce superior diffusion kinetics of Li ions. This work provided a facile strategy to fabricate N/O codoping carbon derived from the renewable resource of CNC, and it is expected to be a promising candidate anode material for Li-ion batteries application.