Pyrolysis Of Glucose Research Articles

A strategy to deposit nano metals in multi-layer graphene for scalable synthesis of high performance anode materials in lithium ion battery

A facile and scalable method for deposition of nano metals in multi-layer graphene is developed. Nano Sn-graphene hybrid (Sn@Gr) is prepared for high performance anode in lithium ion battery, via the in-situ deposition of Sn nanoparticles in multi-layer graphene through pyrolysis of glucose and tin chloride in molten salts with addition of ammonium chloride. The synthesized Sn@Gr demonstrates a lithiation capability (1000 mAh g−1 of Sn@Gr) higher than the dual lithiation capacity from graphite and Sn. The in-situ formed Sn nanoparticles not only expand the interlayer space of the multi-layer graphene to increase the lithiation capacity of graphene but also bridge the graphene sheets to enhance the electrical conduction in longitudinal direction of graphene sheet, leading to the excellent rate performance. The mechanical toughness of the graphene coupled with the firm connection between nano-Sn and graphene sheet contributes the enhanced durability of the Sn@Gr anode. Both lithiation and delithiation capacities of 671 mAh g−1 remain even after 700 cycles at a current of 800 mA g−1. A stable rate capacity as high as 606 mAh g−1 has been achieved at a current of 1000 mA g−1.

Evaluation of Primary Reaction Pathways in Thin-Film Pyrolysis of Glucose Using 13C Labeling and Real-Time Monitoring

There recently has been progress on the fundamental understanding of fast pyrolysis as a promising strategy for biorenewable energy. An example of this progress is the dissection of bulk-sum models into individual molecular reactions as an effort to explain and predict the product yields in biomass pyrolysis. However, rigorous efforts have been scarce to experimentally validate each molecular reaction in pyrolysis. In this work, we evaluate molecular reaction mechanisms in the pyrolysis of glucose labeled with 13C on the C-1, C-3, or C-6 position. We adopt a novel experimental system that we have recently developed to study isothermal reaction kinetics with a very short reactor residence time (∼0.2 s) in virtual real time, which is ideally suited to correlate the results with primary reactions in theoretical modeling. We were able to support the previously proposed primary reaction mechanism for C4H8O4 (erythrose) but reject those for C3H6O3 (dihydroxyacetone and glyceraldehyde) and C3H6O2 (acetol). Alter...

Synthesis of cobalt-impregnated carbon composite derived from a renewable resource: Characterization and catalytic performance evaluation

A novel nitrogen-doped biochar embedded with cobalt (Co-NB) was fabricated via pyrolysis of glucose pretreated with melamine (N donor) and Co(II). The Co-NB showed high catalytic capability by converting p-nitrophenol (PNP) into p-aminophenol (PAP) by NaBH4. The analyses of FE-SEM, TEM, BET, XRD, Raman, and X-ray photoelectron spectroscopy XPS of the Co-NB showed hierarchical porous structure (BET 326.5m2g−1 and pore volume: 0.2403cm3g−1) with well-dispersed Co nanoparticles (20–60nm) on the N-doped graphitic biochar surface. The Co-NB showed higher PNP reduction capability compared to the Co-biochar without N-doping, achieving 94.3% removal within 4min at 0.24gL−1 catalyst dose and initial concentration of 0.35mM PNP. Further conversion experiments under varying environmental conditions (e.g., NaBH4 concentration (7.5–30mM), biochar dosage (0.12–1.0gL−1), initial PNP concentration (0.08–0.17mM)) were conducted in batch mode. The reusability of Co-NB was validated by the repetitive conversion experiments (5cycles). The overall results demonstrated biochar potential as catalysts for environmental applications if properly designed.

Insight into the Formation of Anhydrosugars in Glucose Pyrolysis: A Joint Computational and Experimental Investigation

Fast pyrolysis of glucose/cellulose will produce abundant 1,6-anhydro-β-d-glucopyranose (known as levoglucosan, LG) as the predominant anhydrosugar product, together with certain amounts of other anhydrosugars, mainly including 1,6-anhydro-β-d-glucofuranose (AGF), 1,4:3,6-dianhydro-α-d-glucopyranose (DGP), 1,5-anhydro-4-deoxy-d-glycero-hex-1-en-3-ulose (APP), 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one (LAC). The formation mechanisms of the latter four anhydrosugar products are not well-known at present. Substantiated by analytical pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) experiments, quantum chemistry calculations are employed to give a deep insight into their formation mechanisms in this study. The anomeric effect of glucopyranose has a distinct effect to their formation. DGP is mainly derived from α-d-glucopyranose which plays a vital role in the formation of 1,4-acetal ring. On the contrary, APP and LAC can merely derive from β-d-glucopyranose due to the dehydration at 1-OH + 2-H sit...

Mechanism of Microwave‐Assisted Pyrolysis of Glucose to Furfural Revealed by Isotopic Tracer and Quantum Chemical Calculations

Glucose labeled with 13 C or 18 O was used to investigate the mechanism of its conversion into furfural by microwaveassisted pyrolysis. The isotopic content and location in furfural were determined from GC-MS and 13 C NMR spectroscopic measurements and data analysis. The results suggest that the carbon skeleton in furfural is mainly derived from C1 to C5 of glucose, whereas the C of the aldehyde group and the O of the furan ring in furfural primarily originate from C1 and O5 of glucose, respectively. For the first time, the source of O in the furan ring of furfural was elucidated directly by experiment, providing results that are consistent with predictions from recent quantum chemical calculations. Moreover, further theoretical calculations indicate substantially lower energy barriers than previous predictions by considering the potential catalytic effect of formic acid, which is one of the pyrolysis products. The catalytic role of formic acid is further confirmed by experimental evidence.

Preparation of nitrogen-doped Cu-biochar and its application into catalytic reduction of p-nitrophenol.

Nitrogen-doped copper-biochar (N-Cu-biochar) was synthesized via pyrolysis of glucose in the presence of copper and melamine and used as a catalyst in the reduction of p-nitrophenol by NaBH4. N-Cu-biochar was characterized by field emission scanning electron microscopy/energy-dispersive spectroscopy, Raman spectroscopy, X-ray Diffraction, and Brunauer-Emmett-Teller surface analyzer. The catalytic performance of N-Cu-biochar was evaluated under varying conditions of NaBH4 concentration, biochar dosage, and initial p-nitrophenol concentration. N-Cu-biochar was composed of ~83% C, ~9% O, and ~8% Cu, with Cu/Cu2O phases evenly dispersed on graphitic carbon aggregates possessing both macro- and meso-pores. N-Cu-biochar showed superior catalytic ability in mediating p-nitrophenol reduction as compared to Cu-biochar and N-doped biochar, achieving complete reduction of 0.35mM p-nitrophenol within 30min at a dose of 0.25gL-1. Reduction of p-nitrophenol catalyzed by N-Cu-biochar followed pseudo-first-order kinetics, and the reaction rate was dependent upon NaBH4 concentration. The overall results indicate that biochar can be a suitable candidate as a support for catalyst synthesis, and N-doped Cu-biochar can be a promising catalyst for the reduction of p-nitrophenol.

Facile visual colorimetric sensor based on iron carbide nanoparticles encapsulated in porous nitrogen-rich graphene

Herein, via one-step pyrolysis of glucose, dicyandiamide (DCDA) and Fe containing metal–organic framework (Fe-MOF), small Fe3C nanoparticles were in-situ decorated in 3D porous network of N-rich graphene (NGr). The Fe-MOF served as size regulating precursor, layered g-C3N4 (derived from pyrolysis of DCDA) acted as not only a template to guide the growth of small Fe3C nanoparticles, but also the carbon source for 3D porous NGr network. The intrinsic peroxidase-like catalytic activity of Fe3C/NGr was unpredictably discovered, by taking the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) with H2O2 as a protocol. Fast and distinguished color change, improved stability in exposure to extreme H2O2 concentration and high temperature were obtained. The Michaelis–Menten kinetics was investigated. The detection of glucose was accomplished over a wide concentration range of 2.0~500.0μM with a detection limit lower than most of other similar systems. The reliability of the present sensor was further evaluated by practical monitoring glucose in diluted serum samples. Low cost and simple preparation, fast and distinguished color change, high tolerance to extreme H2O2 concentration and high temperature, endow Fe3C/NGr as one of the promising materials for fast visual colorimetry.

A facile and scalable method to prepare carbon nanotube-grafted-graphene for high performance Li-S battery

Abstract A carbon nanotube-grafted-graphene (CNT-g-Gr) is developed for enhancements of electrical conduction and polysulfide (PS) absorption to improve rate performance and cycleability of lithium-sulfur battery. The CNT-g-Gr is prepared through CNT growth on Ni-deposited graphene sheet which is fabricated via pyrolysis of glucose in a molten salt. The obtained CNT-g-Gr shows much higher specific surface area and PS adsorption capability than graphene. The in-situ formed Ni nanoparticles on graphene sheet not only serve as the catalytic sites for CNT growth, but also function as the anchor-sites for polar PS absorption. The CNT-g-Gr contributes a superb PS adsorption capability arising from graphene and CNT absorbing weakly-polar PS species, and Ni nanoparticles absorbing the species with stronger polarity. The resultant Li-S battery with the CNT-g-Gr shows excellent cycleability and rate performance. A stable discharge capacity of 900 mAh g−1 (with low capacity degradation rate) and a rate capacity of 260 mAh g−1 at 30 C discharge rate have been achieved.

Platform Chemicals via Zeolite‐Catalyzed Fast Pyrolysis of Glucose

AbstractFuran derivatives, such as 5‐hydroxymethylfurfural (HMF) and furfural, obtained from renewable feedstocks are sustainable alternatives to petroleum‐based building blocks for the manufacture of chemical products. This study shows for the first time the applicability of the catalytic fast pyrolysis (CFP) of glucose over tailored zeolites for the production of HMF and furfural. In particular, we demonstrate that Lewis‐acid‐containing faujasite zeolites attained by alkali metal–cation exchange exhibit combined yields to these platform molecules of 17 %. Despite the fact that further research is required on the process assessment at a larger scale and under more realistic conditions, CFP has potential for the production of biomass‐derived commodity chemicals.

Investigation of the Lithiation Mechanism of Fe3O4‐Based Composite Anode: the Effect of the Carbon Matrix

AbstractIn this work, the Fe3O4/CNTs composite and Fe3O4/C composite were synthesized by a facile hydrothermal method without any reducing agents and pyrolysis of glucose, respectively, and the process of the first lithiation of commercial Fe3O4, Fe3O4/CNTs and Fe3O4/C electrode were systematically investigated by EIS as function of electrode potential. It is found that at intermediate degrees of intercalation, the characteristic Nyquist plots of Fe3O4 electrode are composed of three parts, namely, the small semicircle in high‐frequency region can be attributed to the migration of lithium‐ion through SEI film (the resistance of SEI film coupled with SEI film capacitance) as well as contact problems; the semicircle in the medium‐frequency region is attributed to the electronic properties of the material and the large arc in low‐frequency region is due to charge transfer step. Moreover, the changes of kinetic parameters for lithiation process of Fe3O4/CNTs composite as a function of electrode potential in the first discharge cycle was discussed in detail, and the effect of carbon matrix type on the electrochemical performance and lithiation mechanism of Fe3O4 electrode is given.

Temperature-programmed reduction of nickel steam reforming catalyst with glucose

Temperature-programmed reduction (TPR) of a NiO/α-Al2O3 steam reforming catalyst with glucose under a N2 flow was investigated using TGA-FTIR technique. A series of catalyst samples obtained at different temperatures during the TPR were characterised by XRD, CHN elemental analysis, SEM-EDX and TPO. Results showed that the whole TPR covering from room temperature to 900°C consisted of two reactive processes. They were glucose pyrolysis producing carbonaceous materials (char), and NiO reduction by the char resulting in CO2 as a main product. When the initial mass ratio of glucose to the catalyst was 1:10, the catalyst could be completely reduced without carbon remaining. Moreover, two mass loss peaks were observed at around 440°C and 670°C, respectively, during the reduction. Based on the experiments of char characterisation, H2 TPR and excess glucose TPR, a two-stage reduction mechanism was proposed. The first reduction stage was attributed to a solid reaction between NiO and char. The second stage was assigned to NiO being reduced by the CO produced by char gasification with CO2. Their apparent activation energies were 197±19kJ/mol and 316±17kJ/mol, respectively, estimated using the Kissinger method.

Theoretical investigation on the carbon sources and orientations of the aldehyde group of furfural in the pyrolysis of glucose

Furfural (FF) is a valuable and characteristic product of glucose pyrolysis, but little attention has been focused on its formation mechanism. In this study, density functional theory (DFT) methods were employed to investigate the possible pathways leading to the formation of FF from glucose. The results indicate that the pyrolysis of hydroxymethyl furfural (HMF) to FF is hardly to occur duo to the high activation energy (86.3 kcal/mol) required. The dominant FF formation pathway is Path-B2 which involves the 3-deoxy-glucose (3-DG) intermediate with overall energy barrier of 87.2 kcal/mol. The major proportions of FF are derived from C1–C5 of glucose and the aldehyde group in FF formed at C1 is dominant over that at C5. FF involving the C2–C6 of glucose, which include two orientations (C2 and C6) of the aldehyde group only account for a minor proportion.

Upgrading of aromatic compounds in bio-oil over ultrathin graphene encapsulated Ru nanoparticles

A novel Ru@G-CS composite, in which 1–2 layered N-doped graphene encapsulated nano-sized Ru (2.5 ± 1.0 nm) particles, was fabricated on carbon sheets (CS) via the direct pyrolysis of mixed glucose, melamine and RuCl3. And Ru@G-CS-700 (pyrolysis at 700 °C) is highly active, selective and stable for the hydrogenation of model compounds (such as phenols, furfurals and aromatics) in bio-oil in water.

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

The nonselective nature of glucose pyrolysis chemistry can be controlled by preventing the sugar ring from opening and fragmenting.

A facile method to prepare Pt/C/TiO2 nanotubes electrode for electro-oxidation of methanol

In this study, we prepared a Pt/C/TiO2 nanotubes (TiO2NTs) electrode by the facile pyrolysis of chloroplatinic acid and glucose on the TiO2NTs support simultaneously. By several characterization methods such as scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, it was found that with the thermal decomposition of H2PtCl6 and glucose simultaneously, Pt nanoparticles appeared with small particle size and anchored on the surface of TiO2NTs with carbon. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic activity and stability of the prepared electrodes toward the oxidation of methanol. The Pt/C/TiO2NTs electrode possesses a large electrochemically active surface area and exhibits enhanced electrocatalytic activity and better stability for methanol oxidation than the Pt/TiO2NTs electrode. The Pt/C/TiO2NTs electrode provides a new approach for improving the catalytic activity and stability of Pt nanomaterials in renewable energy applications.

Facile synthesis of zinc–iron mixed oxide/carbon nanocomposites as nanocatalysts for the degradation of methylene blue

Zinc–iron mixed oxide/carbon nanocomposites were synthesized by the pyrolysis of ferrocenium, zinc acetate, and glucose without the assistance of template or surfactant. The as-prepared zinc–iron mixed oxide/carbon nanocomposites exhibited good photocatalytic property over methylene blue under UV light.

The Alpha–Bet(a) of Salty Glucose Pyrolysis: Computational Investigations Reveal Carbohydrate Pyrolysis Catalytic Action by Sodium Ions

Biomass pyrolysis is a promising technology for the production of renewable fuels and chemicals from nonfood biomass. Given the potential of pyrolysis as a viable, cost-effective biomass deconstruction method, there is active interest in understanding the chemical transformations at the heart of the technology. It has long been known that the presence of alkali- and alkaline-earth-metal ions in biomass, such as Na+, significantly alters product yields of biomass pyrolysis, but the mechanism behind this effect has not been elucidated. In this work, we employ density functional theory (DFT) to reveal the stereoelectronic basis of the effect of sodium ions on several key glucose thermal decomposition reactions, such as the formation of levoglucosan and 5-hydroxymethylfurfural (5-HMF). β-d-Glucose is of interest for pyrolysis, as it is the monomer of cellulose and a key intermediate in cellulose pyrolysis. α-d-Glucose is included in this study, as the two anomers can readily interconvert under pyrolysis condi...

Simple One-Step Synthesis of Aromatic-Rich Materials with High Concentrations of Hydrothermally Stable Catalytic Sites, Validated by NMR

We report a facile one-step synthesis of aromatic-rich materials that contain high concentrations of Bronsted acidic or basic groups attached via alkyl linkers, which previous work has shown to be particularly hydrothermally stable. The method is based on the Maillard reaction and low-temperature (250 °C) pyrolysis of glucose with primary amines linked to acidic sulfonic or phosphonic functionalities or basic piperidine or pyridine groups. The resulting black, carbon-rich materials were characterized using one- and two-dimensional solid-state 13C and 15N NMR, supplemented by elemental analysis. Synthesis with 13C-enriched glucose enabled a selective NMR characterization of the aromatic scaffold, which is composed mostly of interlinked pyrrole, indole, and pyridine rings. The fraction of sp2-hybridized C in the matrix is 72%; the aromaticity is ∼60% for the sulfonic-acid functionalized material made from glucose and taurine in a 1:1 molar ratio, where sulfur exceeds 11 wt %. The alkyl linkers remained inta...

The Alpha–Bet(a) of Glucose Pyrolysis: Computational and Experimental Investigations of 5-Hydroxymethylfurfural and Levoglucosan Formation Reveal Implications for Cellulose Pyrolysis

As biomass pyrolysis is a promising technology for producing renewable fuels, mechanistic descriptions of biomass thermal decomposition are of increasing interest. While previous studies have demonstrated that glucose is a key primary intermediate and have elucidated many important elementary mechanisms in its pyrolysis, key questions remain. For example, there are several proposed mechanisms for evolution of an important product and platform chemical, 5-hydroxymethylfurfural (5-HMF), but evaluation with different methodologies has hindered comparison. We evaluated a host of elementary mechanisms using a consistent quantum mechanics (QM) level of theory and reveal a mechanistic understanding of this important pyrolysis pathway. We also describe a novel route as a target for catalyst design, as it holds the promise of a more selective pathway to 5-HMF from glucose. We further demonstrate the effect of conformational and structural isomerization on dehydration reactivity. Additionally, we combined QM and ex...

Analytical Fast Pyrolysis of Glucose, Cellubiose and Cellulose: Comparison of the Pyrolytic Product Distribution

Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was employed for the fast pyrolysis of glucose, cellubiose and cellulose in this study. The pyrolytic products from the three glucose-based materials were determined and compared to reveal the distribution differences. The results indicated that fast pyrolysis of the three materials obtained similar pyrolytic products, including the anhydrosugars, furans, linear carbonyls and cyclopentanones, but the distribution of the pyrolytic products differed from each other. The cellulose formed more anhydrosugars, but less carbonyls and furans than the glucose and cellubiose. The glycosidic bond of the cellubiose and cellulose would favor the pyrolytic depolymerization reactions to form various anhydrosugars, while inhibit the pyrolytic fragmentation reactions to produce linear carbonyls.