Hydrothermal Carbonization Of Glucose Research Articles

Hydrothermal carbonization of glucose in saline solution: sequestration of nutrients on carbonaceous materials

In this study, feasibility of selected nutrient sequestration during hydrothermal carbonization (HTC) was tested for three different HTC temperatures (180, 230, and 300 °C). To study the nutrient sequestration in solid from liquid solution, sugar and salt solutions were chosen as HTC feedstock. Glucose was used as carbohydrate source and various salts e.g., ammonium hydrophosphate, potassium chloride, potassium sulfate, and anhydrous ferric chloride were used as source of nitrogen and phosphorus, potassium, and iron, respectively. Solid hydrochar was extensively characterized by means of elemental, ICP-OES, SEM-EDX, surface area, pore volume and size, and ATR-FTIR to determine nutrients’ sequestration as well as hydrochar quality variation with HTC temperatures. The spherical mesoporous hydrochars produced during HTC have low surface area in the range of 1.0–3.5 m 2 g −1 . Hydrochar yield was increased about 10% with the increase of temperature from 180 °C to 300 °C. Nutrient sequestration was also increased with HTC temperature. In fact, around 71, 31, and 23 wt% nitrogen, iron, and phosphorus were sequestered at 300 °C, respectively. Potassium sequestration was very low throughout the HTC and maximum 5.2% was observed in solid during HTC.

Facile template-directed synthesis of carbon-coated SnO2 nanotubes with enhanced Li-storage capabilities

Herein, a novel type of carbon-coated SnO2 nanotubes has been designed and synthesized through a facile two-step hydrothermal approach by using ZnO nanorods as templates. During the synthetic route, SnO2 nanocrystals and carbon layer have been uniformly deposited on the rod-like templates in sequence, meanwhile ZnO nanorods could be in situ dissolved owing to the generated alkaline and acidic environments during hydrothermal coating of SnO2 nanocrystals and hydrothermal carbonization of glucose, respectively. When utilized as an anode material in lithium-ion batteries, the carbon-coated SnO2 nanotubes manifests markedly enhanced Li-storage capabilities in terms of specific capacity and cycling stability in comparison with bare SnO2 nanocrystals.

Carbon-based strong solid acid for cornstarch hydrolysis

Highly sulfonated carbonaceous spheres with diameter of 100–500nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180°C for 4h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91mg/mL could be obtained by hydrolyzing 20mg/mL cornstarch at 150°C for 6h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

Halloysite nanotubes induced synthesis of carbon/manganese dioxide coaxial tubular nanocomposites as electrode materials for supercapacitors

Halloysite nanotubes@carbon/manganese dioxide nanocomposites (HNTs@C/MnO2) with coaxial tubular structure were prepared by introducing manganese dioxide on the surface of carbon-coated halloysite nanotubes (HNTs@C). The HNTs@C nanocomposites were synthesized by hydrothermal carbonization of glucose on the surface of HNTs and further activated at high temperature to improve the degree of carbonization. The use of halloysite nanotubes can effectively induce the heterogeneous deposition of carbonaceous species on the surface of the halloysite nanotubes, and then uniformly generate MnO2 nanoflakes via the redox reaction between the carbon and potassium permanganate to construct the hybrid coaxial structure. The as-prepared hybrid materials were characterized by transmission electron microscope, Fourier transform infrared spectrum, X-ray diffraction, and thermogravimetric analysis. The specific capacitance of HNTs@C/MnO23 nanocomposites can reach 274 F g−1 at 1.25 mA cm−2 in 1.0 M Na2SO4 electrolyte after correcting the weight percent of electroactive materials. Furthermore, the special coaxial tubular structure and the manganese dioxide nanoflakes facilitated the ion diffusion between the electrode/electrolyte interfaces. The results indicate that the novel coaxial tubular hybrid nanocomposites can be a promising candidate as electrode material for supercapacitors.

Improving lithium–sulfur battery performance via a carbon-coating layer derived from the hydrothermal carbonization of glucose

After wrapping AC–S with a carbon-coating layer, the obtained composite can effectively confine polysulfides.

Novel magnetic carbon based solid acid for alkylation of benzene and dodecene

Novel magnetic carbon based solid acid has been synthesized through the hydrothermal carbonization of glucose with magnetic cores and sulfonation of carbonaceous intermediate with hydroxyethylsulfonic acid. The carbon based solid acid owned the core–shell structure and high BET surface, which provided the easily accessible acid sites on the shell. The magnetic solid acid exhibited high activities for the hydrophobic alkylation of benzene and dodecene with complete conversion of dodecene, which was difficult for the traditional carbon based acids for low hydrophilic surface. The simple magnetic recovery process and high stability added the advantages of the solid acid. The high activities, reusability and simple recovery process were the key properties of the solid acid, which hold great potential for green chemical processes.

Functionalized Carbon Spheres for Extraction of Nanoparticles and Catalyst Support in Water

Increased use of nanomaterials in commercial products will lead to environmental contamination in the near future. So far, limited adsorbents are available for the removal of such emerging pollutants from water. The objective of this work was to synthesize functionalized carbon nanospheres (C-spheres) for the removal of emerging nanopollutants from water and to study the mechanisms involved. C-spheres were prepared using hydrothermal carbonization of glucose. Post-modification with polyethylenimine (PEI) generated amine-coated C-spheres, followed by protonation using diluted acid solution. The surface functional groups and morphologies of the C-spheres were characterized using infrared spectroscopy and field emission scanning electron microscopy, respectively. The C-spheres were used for the extraction of citrate-capped gold and silver nanoparticles from water. The equilibrium adsorption data was interpreted using Langmuir and Freundlich isotherms, and the adsorption mechanism was investigated using kinet...

A new metal-free carbon hybrid for enhanced photocatalysis.

Carbon nitride (C3N4) is a layered, stable, and polymeric metal-free material that has been discovered as a visible-light-response photocatalyst. Owing to C3N4 having a higher conduction band position, most previous studies have been focused on its reduction capability for solar fuel production, such as hydrogen generation from water splitting or hydrocarbon production from CO2. However, photooxidation ability of g-C3N4 is weak and has been less explored, especially for decomposition of chemically stable phenolics. Carbon spheres prepared by a hydrothermal carbonization of glucose have been widely applied as a support material or template due to their interesting physicochemical properties and the functional groups on the reactive surface. This study demonstrated that growth of carbon nanospheres onto g-C3N4 (CN-CS) can significantly increase the photooxidation ability (to about 4.79 times higher than that of pristine g-C3N4) in phenol degradation under artificial sunlight irradiations. The crystal structure, optical property, morphology, surface groups, recombination rate of electron/hole pairs, and thermal stability of CN-CS were investigated by a variety of characterization techniques. This study contributes to the further promising applications of carbon nitride in metal-free catalysis.

Activated carbon xerogels with a cellular morphology derived from hydrothermally carbonized glucose-graphene oxide hybrids and their performance towards CO2 and dye adsorption

We report the preparation of micro-/mesoporous carbon monolithic xerogels by means of a two-step approach that comprises (1) hydrothermal carbonization of glucose in the presence of graphene oxide (GO) sheets as morphology-directing agents and (2) chemical activation of the resulting hydrothermal carbon (HTC) xerogels with KOH. The as-prepared HTC xerogels were made up of a random assembly of thin (<30nm) carbon platelets, which were interpreted to arise via dehydration and condensation reactions of glucose at catalytically active (acidic) sites present on the surface of GO. The chemical activation afforded xerogels with large surface areas and pore volumes (up to ∼2000m2g−1 and 1.15cm3g−1, respectively) and a cellular morphology, which could be attributed to the combined effect of the activating agent and the unusual, compliant nature of the HTC xerogel. Additionally, the use of different activation conditions allowed fine-tuning the porous texture of the activated xerogels. Finally, the activated carbon xerogels displayed CO2 uptake capacities up to 4.9mmolg−1 at 0°C and 1bar, as well as an efficient performance (between 600 and 700mgg−1) in the adsorption of bulky dyes, thus demonstrating their application potential.

Synthesis of tantalum pentoxide hollow spheres utilizing a sacrificial templating approach

A hydrothermal route to synthesize tantalum pentoxide (Ta2O5) hollow spheres (TPHSs) using tantalum pentaethoxide (Ta(OET)5) as the oxide precursor and glucose-derived carbonaceous spheres (CSs) as the sacrificial templates have been described. The carbonaceous spheres (CSs) were first prepared by hydrothermal carbonization of glucose, then a controlled coating of the template surface by Ta2O5 nanoparticles via the hydrolyzing of tantalum pentaethoxide at ambient temperature was implemented. Subsequent removal of the interior carbonaceous cores by pyrolytic treatment through oxidation in air produces freestanding TPHSs. The obtained TPHSs were characterized by means of SEM, TEM, XRD, and IR spectroscopy.

One-step preparation of carbonaceous solid acid catalysts by hydrothermal carbonization of glucose for cellulose hydrolysis

Carbonaceous materials (CM-SO3H, CM-COOH) were prepared and functionalized in-situ in a single step with SO3H or COOH groups by hydrothermal carbonization of glucose in the presence of sulfosalicylic acid or acrylic acid as co-monomer. The prepared materials were evaluated as solid acid catalysts and exhibited good catalytic activity for the hydrolysis of cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). Remarkably, the carbonaceous materials obtained by the hydrothermal carbonization of glucose could be used directly for the catalytic hydrolysis of cellulose without any post-modification or in-situ functionalization and were surprisingly efficient.

Attapulgite oriented carbon/polyaniline hybrid nanocomposites for electrochemical energy storage

Attapulgite@carbon/polyaniline (APT@C/PAn) hybrid nanocomposites were fabricated by in situ chemical oxidative polymerization of aniline after hydrothermal carbonization of glucose on the surface of the attapulgite. The introduction of attapulgite can effectively guide the heterogeneous deposition of carbonaceous species on the surface of attapulgite and further prevent polyaniline from self-aggregation. The obtained hybrid nanocomposites were characterized by transmission electron microscope, Fourier transform infrared spectrum, X-ray diffraction, and thermogravimetric analysis. The maximum specific capacitance of the APT@C/PAn electrode materials was 324.5Fg−1 after correcting for the weight percent of the electroactive materials at a current density of 2.5mAcm−2 in a 1.0M H2SO4 electrolyte. The excellent performance might be ascribed to the orientation of APT and the combination of the good electrical conductivity of carbon and the pesudocapacitance of polyaniline.

Highly Disordered Carbon as a Superior Anode Material for Room‐Temperature Sodium‐Ion Batteries

Highly Disordered Carbon as a Superior Anode Material for Room‐Temperature Sodium‐Ion Batteries

Salt and sugar: direct synthesis of high surface area carbon materials at low temperatures via hydrothermal carbonization of glucose under hypersaline conditions

Hydrothermal carbonization of carbohydrates, here glucose as a model, in salt–water mixtures results in high surface area carbonaceous materials with surface areas up to 650 m2 g−1 where porosity is created by aggregation of very small primary nanoparticles, similar to aerogels or high surface area soot. These materials can be obtained by simple washing with water and are useful without further activation processes. Furthermore, no special technical equipment for isolation is needed since the materials are exceptionally stable throughout vacuum drying, thus keeping the overall approach sustainable and very simple.

WS2 nanoparticles–encapsulated amorphous carbon tubes: A novel electrode material for supercapacitors with a high rate capability

The present communication reports on the preparation of WS2 nanoparticles–encapsulated amorphous carbon tubes (WS2NPs/CTs) via two-step processes. Firstly, CTs were grown in anodic aluminum oxide (AAO) film by hydrothermal carbonization of glucose. Secondly, the as-prepared CTs/AAO film was impregnated with (NH4)2WS4 followed by high temperature treatment in Ar atmosphere. We further demonstrate the application of the resulting WS2NP/CT composites as a novel electrode material for supercapacitor. Such composites were found to deliver a specific capacitance of 337F/g at a high current density of 10A/g with good cycle stability.

Preparation of Multi‐Metal Oxide Hollow Sphere Using Layered Double Hydroxide Precursors

AbstractA simple and versatile synthesis method was developed to prepare inorganic multi‐metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides (LDH) with pre‐determined compositions were used as precursors for multi‐metal oxides and carbon spheres (CSs) prepared by hydrothermal carbonization of glucose were used as hard templates. Electrostatic force drove the positively charged LDH nanosheets to be anchored by the negatively charged CSs once they were mixed, leading to the formation of core‐shell structures. Finally, multi‐metal oxides with hollow spherical structures were obtained by calcination. These hollow spheres were characterized by X‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and inductively coupled plasma (ICP). Results revealed that the as‐prepared oxide hollow spheres could exactly inherit the metal‐to‐metal ratios of initial LDH precursors, which provided an effective way to control the compositions of oxide shells. This strategy was suitable for preparation of a series of oxide hollow spheres from binary to multi‐component ones, including MgO/Al2O3, MgO/Fe3O4, NiO/Al2O3, and ZnO/NiO/Al2O3.

Hollow Carbon Nanospheres with Superior Rate Capability for Sodium‐Based Batteries

Hollow carbon nanospheres are synthesized via the hydrothermal carbonization of glucose in the presence of nanosized latexes templates. The resulting disordered carbon hollow nanospheres exhibits excellent characteristics in terms of reversible capacities, cycling performance, and rate capability for application as an anode material in Na-based batteries.

Synthesis of Colloidal Carbon Spheres by Hydrothermal Carbonization of Glucose at Different Initial pH

In this paper, carbon spheres with different size distributions are obtained by hydrothermal carbonization of glucose via varying the reaction conditions including concentration of glucose solution, hydrothermal reaction time and the initial pH values of solutions. The initial pH values of glucose solutions play an important role in the size distribution of the carbon spheres. The formation and growth mechanisms of carbon spheres at different initial pH levels are discussed and proposed.

Catalytic deposition of nanocarbon onto palygorskite and its adsorption of phenol

A novel palygorskite/carbon sorbent was synthesized by hydrothermal carbonization of glucose onto palygorskite using ammonium ferrous iron (Fe 2+) sulphate hexahydrate as catalyst under mild conditions. The resulting palygorskite/carbon nanocomposites were characterized by field-emission scanning electron microscopy, X-ray diffraction patterns, Fourier transform infrared spectroscopy and total carbon content analysis. It was found that the nano-carbon with diameter of 30–50 nm was successfully loaded onto the palygorskites crystal surfaces, accompanied by abundant C―H groups. The mechanism of formation of nanocomposites was proposed as follows. Two carbonization routes of glucose coexisted, namely random carbonization and adsorption-induced carbonization on palygorskite surfaces. The formation of palygorskite/carbon was determined by competition of the two carbonization routes which could be controlled by hydrothermal conditions, i.e. reaction time, temperature and catalyst. The resultant modified palygorskite demonstrated a substantially high adsorption capacity for phenol in comparison with unmodified palygorskite.

Hydrothermal carbon spheres containing silicon nanoparticles: synthesis and lithium storage performance

Spherically shaped carbon/silicon nanocomposites have been obtained in a one-step procedure using hydrothermal carbonization of glucose in the presence of commercially available silicon nanoparticles and have been tested electrochemically as an anode material for lithium-ion batteries.