Synthesis Of Carbon Research Articles

Functionalization of ionic liquids for heterogeneous catalysis in CO2 conversion: Cycloaddition of epoxides and hydrogenation

The mitigation of environmental impacts caused by greenhouse gas emissions has become increasingly urgent, and the use of CO2 as a primary carbon source is an alternative in chemical transformations, including the synthesis of organic carbonates, formic acid, or methanol. This work aims to synthesize ionic liquids from the imidazolium cation family to be used in the cycloaddition of CO2 with ILs anchored in SiO2-clay heterostructure, MCM-41 and KIT-6 mesoporous materials, as well as the hydrogenation of CO2 with ILs added to ruthenium complexes, i.e., two catalytic systems. The most satisfactory result for CO2 cycloaddition (TON PC = 226) was obtained using the IL (MeO)3Sipmim.Cl anchored in SiO2-clay heterostructure (0.16 mol%) as the catalyst and ZnBr2 (0.04 mol%) as the co-catalyst. The hydrogenation was conducted with the IL (edaO)3Sipmim.Cl and the ruthenium complex Ru-PNN were not successful, but with co-catalyst PEHA, formic acid/formamide was produced (TON Form = 552). The unique catalytic system that showed activity for forming methanol was the commercial Ru-MACHO, Ru-C29H30ClNOP2, (TON MeOH = 3.3). These results highlight the potential of ruthenium-based complexes and supported ionic liquids as active systems in CO2 conversion.

One-Step Carbonization Synthesis of N, S Co-Doped Carbon Materials Derived from Agricultural Waste Peanut Shells for High-Performance Symmetric Supercapacitors.

Biomass carbon has the advantages of wide source, low cost and environmental protection, and has been widely used in the field of electrochemical energy storage. In this work, N and S co-doped carbon materials were prepared by using peanut shell as carbon source and thiourea as activator. When the peanut shell and activator were 2 g and 4 g, respectively, the prepared NSPC-4 had the largest specific surface area and special pore structure. Elemental analysis showed that the activator introduced more N, S and O atoms to the carbon material, and more heteroatoms helped to improve the surface structure of the carbon material and provide additional pseudocapacitance. In addition, NSPC-4 contains a short-range ordered graphite structure, which can provide excellent electrical conductivity. The electrochemical test results show that NSPC-4 has the largest specific capacitance. When the mass of the activator is higher than or below 4 g, the electrochemical performance of the carbon material will be reduced. The symmetric supercapacitor (SSC) assembled by NSPC-4 has an energy density of 8.3 Wh kg-1 when the power density is 350 W kg-1. The synthesis method is not only simple, green and economical, but also has important application value.

A facile synthesis of N-doped carbon encapsulated multimetallic carbonitride as a robust electrocatalyst for oxygen evolution reaction

Electrocatalytic water splitting is a promising solution for generating clean hydrogen. Transition metal compounds are among the most extensively investigated catalysts developed to date for water oxidation in alkaline media, a process also known as the oxygen evolution reaction (OER). However, the application of these catalysts was constrained by insufficient stability arising from surface oxidation and metal dissolution under high OER potential. In this work, we developed a facile approach using urea-based gel as the precursor of preparing a series of multimetallic carbonitride particles which were encapsulated by N-doped carbon (NC). In particular, (MoCoFeNiZr)CN@NC core–shell structure delivered a low overpotential of 246 mV at a current density of 10 mA cm−2 in 1 M KOH during OER. Importantly, operando differential electrochemical mass spectrometry (DEMS), together with multiple microscopic and spectroscopic analyses, indicated that the NC shells effectively maintained the crystalline stability of carbonitride via suppressing the surface reconstruction during catalysis. The highly graphitic NC also demonstrates excellent stability against oxidation. This work shows a promising strategy of stabilizing electrocatalyst at high anodic potential, paving the way for the development of robust electrode materials for energy conversion.

Innovative Synthesis and Sodium Storage Enhancement of Closed-Pore Hard Carbon for Sodium-Ion Batteries

Innovative Synthesis and Sodium Storage Enhancement of Closed-Pore Hard Carbon for Sodium-Ion Batteries

Synthesis of hydrothermal carbonation carbon with tunable photocatalytic performance for trimethoprim degradation using an ethanol-water co-solvent strategy: Influence of ethanol concentration

Hydrothermal carbonation carbon (HTCC) is increasingly acknowledged as a promising photocatalytic material for degrading antibiotics in water due to its green and cost-effective properties. While ethanol and water are prevalent solvents in the preparation of HTCC, research examining the influence of solvent combinations on the photocatalytic efficacy of HTCC is lacking. The influence of various ethanol-water co-solvent preparation ratios (0, 20, 40, 60, 80, and 100 wt% ethanol concentration in the co-solvent) on the photocatalytic degradation activity of trimethoprim (TMP) by HTCC was examined in this study. The results indicated that altering ethanol solvent preparation concentrations modulates the morphological characteristics, surface functional groups, and photochemical attributes of co-solvent HTCC materials. HTCC prepared using an 80 wt% ethanol solvent concentration demonstrated the most efficient TMP photocatalytic degradation (>90%). The TMP degradation kinetic constants of 80 wt% ethanol concentration co-solvent HTCC were 3.29 and 1.51 times greater compared to those of HTCC prepared using only water or ethanol as solvents, respectively. •O2− predominantly served as the key reactive oxygen species in TMP photocatalytic decomposition by 80 wt% ethanol concentration co-solvent HTCC, with its generation mechanism linked to the intrinsic furan donor-acceptor (D-A) conjugated structure of HTCC. An increase in ethanol solvent preparation concentration promotes the formation of more furan units, increased coupling of donor-acceptor (D-A) conjugation, a lower D-A ratio, and enhanced generation of short-chain aliphatics in HTCC, which then directly impacts its electron transfer capability, bandgap structure, light absorption capacity, and photocatalytic degradation efficiency. This work provides fresh strategies for the preparation and photocatalytic performance modulation of water treatment photocatalysts based on HTCC.

Green self-templated synthesis of P-doped mesoporous carbon from dual sodium salts with improved average pore size for capacitive deionization

Mesoporous carbon materials hold significant potential in capacitive deionization (CDI) technology owing to expansive accessible surface area, more adaptable pore structure, excellent conductivity properties and effective surface modification and functionalization. While templating is a common method for synthesizing mesoporous carbons, the commonly used hard and soft templating approaches among them suffer from the challenges of expensive precursors and templating agents, complex procedures, secondary contaminants and difficulties in template removal. In contrast, the self-templating method not only circumvents the traditional template removal or combustion steps but also eliminates the use of organic solvents and hazardous chemicals, thus minimizing environmental impact. In this paper, we have successfully synthesized phosphorus-doped mesoporous carbon with a large average pore size (paver) using a green and convenient self-templating method employing dual sodium salts of sodium alginate (SA) and sodium phytate (SP). Compared to single SA (6.76 nm) or SP (3.74 nm) self-templated carbonization, the average pore size of carbon materials obtained from dual self-templated carbonization with a proportional mixture (12.97 nm) is significantly improved. The larger average pore size provides a greater surface area for electrode-electrolyte interactions, allowing for easier access and faster diffusion of ions into the pores, thereby enhancing the electrochemical and capacitive deionization properties of the material. The resulting material demonstrates promising electrochemical and desalination performance as evidenced by possessing a specific capacitance of 175.8 A/g and an adsorption capacity of 19.65 mg/g, underlining its potential for application in capacitive deionization utilizing mesoporous carbon materials with large average pore size.

Mesostructured Bifunctional ZnBr2/g‐C3N4 Catalysts Towards Efficient Cocatalyst‐Free Cycloaddition of CO2 to Propylene Carbonate

AbstractCatalytic cycloaddition of CO2 with propylene oxide (PO) is a sustainable pathway for the synthesis of propylene carbonate (PC), and the design of efficient heterogeneous catalysts is a hot research topic in both C1 chemistry and functional materials. In this work, graphitic carbon nitride (g‐C3N4) materials were prepared using urea (U) and melamine (M) as precursors through one‐step thermal condensation and then applied as catalyst supports for ZnBr2. As heterogeneous catalysts, the synthesized composites (ZnBr2/g‐C3N4‐MU) exhibited higher activity in the cycloaddition reaction of CO2 to PC than ZnBr2/g‐C3N4‐M and ZnBr2/g‐C3N4‐U. The preparation temperature of ZnBr2/g‐C3N4‐MU could affect the distributions of nitrogen species and acidic strength, which thus determined the final catalytic activity. More importantly, the loading of ZnBr2 not only introduced acidic sites but also enhanced the strength of alkaline sites of g‐C3N4‐MU, enabling ZnBr2/g‐C3N4‐MU materials as acid–base bifunctional catalysts in cycloaddition of CO2 with PO.

Bimetallic MnZn-MOF-74 with enhanced percentage of MnIII: Efficiently catalytic activity for direct oxidative carboxylation of olefins to cyclic carbonates under mild and solvent-free condition

Multi-functional MOF catalyst with oxidative- and acid- centers showed potential in olefins oxidative carboxylation to cyclic carbonates directly. In this work, a series of bimetallic MnZn-MOF-74 with different molar ratios of Mn and Zn were synthesized successfully through a one-pot facile method. Thoroughly characterization indicated that the existence of Zn regulated the valance state distribution of Mn in the obtained MnZn-MOF-74. Mn99.3Zn0.7-MOF-74 with the highest ratio of MnIII (61.3 %) performed the most efficient activity for olefin direct tandem oxidative carboxylation reaction using aqueous tert-butyl hydroperoxide oxidant under solvent-free condition of 90 °C, 1.0 MPa CO2 and 4 h. Mn99.3Zn0.7-MOF-74 also showed satisfactory versatility and recyclability. Based on the experiments, a feasible mechanism was presented. Thanks to the high ratio of active MnIII as main oxidative center, the coordination unsaturated bimetal Mn and Zn as Lewis-acid sites, O2– of metal − O as Lewis-base sites and combined effect with Bu4NBr cocatalyst, Mn99.3Zn0.7-MOF-74 presented efficient performance for the direct synthesis of cyclic carbonates from olefins. The metal Zn in MOF can regulate the valance state distribution of Mn and result in efficient catalytic property, presenting a potential avenue for direct oxidative carboxylation reaction of olefins to cyclic carbonates synthesis.

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

Smart synthesis of porous carbon with appropriate aperture distribution and high area utilization still retains an enormous challenge for efficient charge storage. Herein, a simple freeze-drying along with subsequent one-step carbonization/activation process is ingeniously devised to fabricate honeycomb-like nitrogen-doped porous carbon (NPC) framework with high-level active N/O-functional groups and hierarchical porous structure including substantial ultra-micropores (<0.7 nm). The underlying formation mechanism of such porous NPC framework is tentatively proposed. By finely regulating the dosage of NaHCO3, the optimized NPC (i.e., NPC114) is endowed with ultra-high surface area utilization of ∼26.4 μF cm−2 at 1 A/g in KOH electrolyte, which is close to theoretical value of electrochemical double-layer capacitance (15–25 μF cm−2), and even larger than the case (∼22.4 μF cm−2) with H2SO4 electrolyte due to the inaccessible ultra-micropores by SO42− of larger size. Similarly, as for the organic system, the as-prepared NPC115 with higher meso- and macropore surface area exhibits higher energy density of 22.36 Wh kg−1 than other counterparts. Furthermore, NPC114, when evaluated as anode material for sodium-ion batteries, exhibited more attractive high-rate Na+-storage properties as well. The in-depth understanding into intrinsic relationship between aperture distribution and electrochemical behaviors will provide meaningful guidance for electrode material design

Synthesis of hierarchical carbon Nanofibers-CoNi/C composites for enhanced microwave absorption efficiency

Developing lightweight, highly absorption and broadband microwave absorbents to combat severe electromagnetic radiation pollution poses a significant challenge. In this study, we designed a novel chain-like CNFs-CoNi/C nanocomposite by in-situ growth of bimetallic MOFs on the CNFs followed by calcination. The resulting CoNi/C composite with hollow structure was uniformly distributed along the 1D CNFs. The unique porous structure and heterogeneous interface derived from MOFs facilitated efficient scattering and multiple reflections of microwaves. By harnessing interfacial polarization loss, dipole polarization loss, and conduction loss mechanisms synergistically, the chain-shaped porous multi-stage CNFs-CoNi/C composite exhibited exceptional microwave absorption performance at a filling ratio of 10 %. It achieves a maximum reflection loss of −70 dB and an absorption bandwidth (EAB) for RL ≤ -10 exceeding 4.82 GHz with a corresponding thickness as low as 1.25 mm. This study introduced a lightweight and highly absorptive material that offers valuable insights into developing high-performance electromagnetic wave absorbing materials through organic composite comprising MOF and carbon materials.

Highly efficient oxygen carrier NiFeP (oxy) hydroxides nanoparticle embedded in N-doped porous carbon derived from bio-waste for bifunctional electrocatalysts

Developing cost-effective, readily available materials for efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting is a crucial step toward enhancing the profitability and sustainability of energy conversion systems. This research introduces a novel synthesis method for NiFeP/NPC OHs from banana peel bio-waste, a method that could revolutionize the field of materials science and electrochemistry. The use of metallic phosphides, known for their excellent electrical conductivity and catalytic activity, as bifunctional catalysts, combined with the efficient synthesis of nanoporous carbons (NPC) from banana peel bio-waste (BPW), could pave the way for a new era of sustainable and cost-effective energy conversion. By chemically activating different porogens, such as nickel, iron, and phosphorus (NiFeP), to form (oxy) hydroxides (OHs), functional carbonaceous structures with a high density of pores and large specific surface areas can be achieved. The resulting materials, designated as NiFeP/NPC OHs, are characterized by their remarkable porosity, high conductivity, large surface area, and chemical stability. These properties make NiFeP/NPC OHs particularly suitable for electrocatalysis, where they exhibit outstanding activity in both HER and OER. The optimized NiFeP/NPC OHs material shows a very low overpotential of 93 mV for HER and 243 mV for OER at 10 mA cm⁻2 and high durability over 100 h. Moreover, the bifunctional NiFeP/NPC OHs electrode demonstrates exceptional catalytic activity and stability in alkaline solutions. This study not only highlights the innovative synthesis of NPC from BPW and the cost-effective fabrication of NiFeP/NPC OHs but also sparks curiosity about the potential of this novel synthesis method.

Synthesis and performance evaluation of bio-derived and synthetic carbon as lithium-sulfur battery cathode

The next-generation of batteries need be both energy dense and environment friendly. Lithium sulfur batteries (LSBs) satisfy both criteria but their practical implementation is marred by the highly resistive nature of sulfur. Carbon-based cathodes play a vital role in mitigating the issue because their high conductivity allows for effective electron transfer during electrochemical cycling. Synthesis and electrochemical evaluation of carbon-based cathodes from two different sources for LSBs was carried out. Herein, two kinds of carbon, namely bio-derived carbon from coconut shells (CC500) and N-doped carbon (NC) from polyacrylonitrile fibers were synthesized and sulfur was incorporated via the melt diffusion route. The composites are characterized by PXRD and TGA, which determined 80 wt% mass loading of sulfur. The higher intensity of G-band over D-band in Raman spectroscopy indicates greater graphitic character for CC500 compared to NC. SEM images show large macro-pore like tunnels in CC500 while NC appears are irregular chunks. EDAX spectra showed 20 wt% N content in NC while CC500 is largely carbon with some minor surface oxygen. In galvanostatic charge–discharge cycling of coin cells, bare CC500/S shows better specific capacity compared to NC/S samples but the trend flips once a separator modified with 4 mg of graphene oxide (GO) is introduced (indicated as NC/S/GO4 and CC500/S/GO4). This points towards synergy between N-doped carbon and GO layer in retaining the soluble polysulfides in the catholyte region. NC/S/GO4 exhibited better capacity i.e., 1453, 1024, 866, 787, 697 mAh/g versus 1016, 779, 672, 551, 441 mAh/g offered by CC500/S/GO4 when discharged at 50, 100, 200, 300 and 500 mA/g, respectively.

Two‐Dimensional Silver–Isocyanide Frameworks

Metal‐organic frameworks (MOFs) have been widely studied due to their versatile applications and easily tunable structures. However, heteroatom‐metal coordination dominates the MOFs community, and the rational synthesis of carbon–metal coordination‐based MOFs remains a significant challenge. Herein, two‐dimensional (2D) MOFs based on silver–carbon linkages are synthesized through the coordination between silver(I) salt and isocyanide‐based monomers at ambient condition. The as‐synthesized 2D MOFs possess well‐defined crystalline structures and a staggered AB stacking mode. Most interestingly, these 2D MOFs, without π–π stacking between layers, exhibit narrow bandgaps down to 1.42 eV. As electrochemical catalysts for converting CO2 to CO, such 2D MOFs demonstrate Faradaic efficiency over 92%. Surprisingly, the CO2 reduction catalyzed by these MOFs indicates favorable adsorption of CO2 and *COOH on the active carbon sites of the isocyanide groups rather than on silver sites. This is attributed to the critical σ donor role of isocyanides and the corresponding ligand‐to‐metal charge–transfer effect. This work not only paves the way toward a new family of MOFs based on metal–isocyanide coordination but also offers a rare platform for understanding the electrocatalysis processes on strongly polarized carbon species.

MnO2 as efficient and robust catalyst for halogen-free synthesis of cyclic carbonate from CO2 and epoxides

Cyclic carbonate is an important fine chemical/intermediate and their synthesis from CO2 and epoxides is economical and green pathway, however, it is still a challenge to develop a efficient and robust catalyst for halogen-free synthesis of cyclic carbonate. Herein, we successfully prepared large-scale MnO2 catalysts by microfluidics method, and the MnO2 especially δ-MnO2 showed >99.9 % propylene carbonate yield under 393 K, 3 MPa CO2 and DMF solvent. Moreover, the initial TOF value over δ-MnO2 on the basis of total catalyst amount was 5.80 h−1, which was the maximum among all the reported heterogeneous metallic oxide catalysts for halogen-free synthesis of propylene carbonate from CO2 and epoxides, and the superior catalytic performance can be ascribed to the abundant moderate acidic–basic active sites on the δ-MnO2 surface and the synergistic effect of δ-MnO2 and DMF. Furthermore, the δ-MnO2 can be reused at least 4 times and exhibited wide substrate applicability.

Nb-doped hydrogenated diamond-like carbon coated biodiesel injectors material: Synthesis, structure and properties

Despite the economic and environmental benefits of biodiesel, it poses significant challenges, including coking on metal surface and increased wear on diesel engine injector nozzles. Therefore, this study investigates the synthesis of niobium-doped diamond-like carbon (Nb-DLC) coatings on two types of injector nozzle materials (viz. H13 steel, AISI 420 stainless steel) using the Closed-Field Unbalanced Magnetron Sputtering (CFUBMS) technique. Comprehensive characterizations, including microstructural analysis, crystal structure evaluation, hardness assessment, and tribological property assessment, were conducted. The Nb-DLC coatings demonstrated a stable friction coefficient, with values four times lower than that of the substrate materials. The present findings demonstrate significant enhancements in terms of structural composition, crystalline phase, hardness, friction coefficients, and adhesion properties due to the Nb-DLC coatings. Therefore, Nb-DLC coated materials could be the promising candidate material for biodiesel engine injector nozzle applications. This emphasizes their potential to contribute significantly to the sustainable consolidation of biodiesel within automotive engine.

The Role of K2CO3 in the Synthesis of Dimethyl Carbonate from CO2 and Methanol

The synthesis of dimethyl carbonate (DMC) from methanol and CO2 has also received widespread attention, and K2CO3 is usually used as a catalyst in the synthesis of DMC. In this work, the role of K2CO3 in synthesizing dimethyl carbonate (DMC) from methanol and CO2 was revisited. Interestingly, NMR results indicated that K2CO3 can react with methanol to form carbonate CH3OCOO−, an essential intermediate in the synthesis of DMC, which can be transformed into DMC in the presence of CH3I. In other words, K2CO3 can act as not only a catalyst but also a reactant to synthesize DMC from methanol and CO2.

One-Pot Synthesis of Propylene Carbonate through Tandem Epoxidation-Cycloaddition Reaction from Propylene and CO2

One-Pot Synthesis of Propylene Carbonate through Tandem Epoxidation-Cycloaddition Reaction from Propylene and CO₂

Synthesis and computational studies for halide‐free, neutral, and bifunctional one‐component ferrocene‐based catalysts for the coupling of carbon dioxide and epoxides

AbstractWe used stable and nontoxic [(dimethylamino)methyl]ferrocene (Fc‐N), (hydroxymethyl)ferrocene (Fc‐O), 1,2‐bis[(dimethylamino)methyl]ferrocene (Fc‐N2), and 1‐[(dimethylamino)methyl]‐2‐(hydroxymethyl)ferrocene (Fc‐NO) as halide‐free, neutral, and bifunctional one‐component catalysts for the synthesis of cyclic carbonates. They do not need halide‐based additives or tethered salts attached to ligands when used for this coupling reaction. Among them, Fc‐N2 exhibited the best catalytic activity under the same reaction conditions. Catalytic activity decreased rapidly in the order Fc‐N2 &gt; Fc‐NO &gt; Fc‐N &gt; Fc‐O, and interestingly, the more amino groups introduced into the Cp groups, the higher the activity. Various terminal and internal epoxides were easily converted into the corresponding cyclic carbonates. Calculations based on the density functional theory were also carried out to elucidate the mechanism of the coupling reaction.

Direct Synthesis of Dimethyl Carbonate from Methanol and CO2 over ZrO2 Catalysts Combined with a Dehydrating Agent and a Cocatalyst

Zirconia nanocrystals as catalysts for the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide have received significant interest recently. In this paper, three zirconia-based catalysts presenting different monoclinic and tetragonal phase contents are prepared and characterized by X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), and temperature-programmed desorption of NH3 and CO2 (NH3-TPD and CO2-TPD). The catalytic performances of these solids are evaluated in terms of DMC production. This production is low when using the bare zirconias, but it is significantly increased in the presence of 1,1,1-trimethoxymethane (TMM) playing the role of a dehydrating agent, which shifts the thermodynamic equilibrium. Moreover, the production of DMC is further improved by adding a second solid catalyst (cocatalyst), the molecular sieve 13X, to accelerate the hydration of TMM. Hence, the molecular sieve 13X plays a dual role by trapping water molecules formed by the reaction of DMC synthesis and providing strong acidic sites catalyzing TMM hydrolysis. To the best of our knowledge, the combination of two solid catalysts in the reaction medium to accelerate the water elimination to obtain higher DMC production from CO2 and methanol has never been reported.

Shape-controllable synthesis of lignin-derived boron-doped nanoporous carbons for dye adsorption and electrochemical H2O2 production

Lignin-derived nanocarbon materials (LNCMs) have attracted intense attention due to their excellent properties and promising applications in renewable energy technologies. However, lignins tend to melt and agglomerate during pyrolysis, make it difficult to control the morphology and pore structure of the resulting carbon. In this study, boron-doped porous nanocarbon (BFC) in various shapes (sphere, band, and sheet) were synthesized using ammonium borate as a crosslinking agent to prevent lignin melting, assisted by liquid nitrogen freeze-drying and potassium phosphate (KP) templating. The effects of BFC structure on methylene blue adsorption and electrochemical generation of H2O2 were investigated. The results show that KP-1/1-8BFC exhibits a high specific surface area (912.89 m2/g) and a hierarchical micro-mesoporous structure, achieving a remarkable adsorption capacity of 473.9 mg/g for methylene blue and rapid kinetics. The selectivity of KP-1/20-8BFC for electrochemical production of H2O2 reaches 85 %. This study offers theoretical guidance for the controllable synthesis of LNCMs, contributing to the advancement of sustainable energy solutions.