Porous Carbon Particles Research Articles

Size-Dependent Effects of ZIF-8 Derived Cathode Materials on Performance of Zinc-Ion Capacitors.

Zinc-ion capacitors (ZICs) have attracted great attention due to a series of advantages. However, the cathode materials are still the bottleneck for high-performance ZICs to be achieved. Therefore, ZIF-8-derived porous carbons are one of the most promising candidates but ZIF-8 nanoparticles with different sizes exhibited various electrochemical performances in ZICs. Herein, a series of monodispersed ZIF-8 nanoparticles are first prepared by a temperature-controlled process to fabricate the corresponding ZIF-8-based porous carbon nanoparticles with pre-designed sizes. The as-prepared materials have been tested as cathode materials in ZICs. Thus, their size effect allowed us to disclose its correlation with other factors such as ion transport/storage and capacitance. The results reveal that the optimal-sized porous carbon particles can effectively shorten the ion transport distance and accelerate the ion diffusion rate, resulting in lower electrical resistance, larger ion diffusion coefficients, and faster electron transport. The presented findings can facilitate the design of new advanced cathode materials paving the way for the development of high-performance cathode materials for ZICs in the future.

Facile oxygen-enriched hierarchical porous carbon particles based on biomass wastes for improving the adsorption of malachite green from aqueous solutions

The abundance of active groups and the surface areas of adsorbents used for the removal of contaminants such as dyes are very important for the effective adsorption process. For this purpose, the high surface area-activated carbon was obtained by activation of agricultural waste chestnut shells as carbon precursor(CSAC) with sodium hydroxide in the first stage of this study. In the second stage, the doping of oxygen atoms with nitric acid was carried out to further improve the surface properties of this activated carbon (O-doped CSAC). The obtained oxygen-rich activated carbon sample was used as an adsorbent to remove a cationic dye malachite green (MG). EDS, SEM, XRD, FTIR and nitrogen adsorption analyses were used for the characterisation of these activated carbon samples. FTIR, elemental analysis and EDS analyses showed a significant increase in the amount of oxygen groups on the surface. The BET surface area obtained for CSAC had a high surface area of 1548 m2/g. Kinetic, thermodynamic and isotherm parameters for the adsorption of MG with O-doped CSAC were determined. The qe values obtained for MG adsorption with O-doped CSAC showed an adsorption efficiency of about 90 %. An adsorption capacity of 284.6 mg g-1 was obtained at 298 K with the Langmuir isotherm. The adsorption mechanism of MG with O-doped CSAC was also investigated.

Optimized Porous Carbon Particles from Sucrose and Their Polyethyleneimine Modifications for Enhanced CO2 Capture

Carbon dioxide (CO2), one of the primary greenhouse gases, plays a key role in global warming and is one of the culprits in the climate change crisis. Therefore, the use of appropriate CO2 capture and storage technologies is of significant importance for the future of planet Earth due to atmospheric, climate, and environmental concerns. A cleaner and more sustainable approach to CO2 capture and storage using porous materials, membranes, and amine-based sorbents could offer excellent possibilities. Here, sucrose-derived porous carbon particles (PCPs) were synthesized as adsorbents for CO2 capture. Next, these PCPs were modified with branched- and linear-polyethyleneimine (B-PEI and L-PEI) as B-PEI-PCP and L-PEI-PCP, respectively. These PCPs and their PEI-modified forms were then used to prepare metal nanoparticles such as Co, Cu, and Ni in situ as M@PCP and M@L/B-PEI-PCP (M: Ni, Co, and Cu). The presence of PEI on the PCP surface enables new amine functional groups, known for high CO2 capture ability. The presence of metal nanoparticles in the structure may be used as a catalyst to convert the captured CO2 into useful products, e.g., fuels or other chemical compounds, at high temperatures. It was found that B-PEI-PCP has a larger surface area and higher CO2 capture capacity with a surface area of 32.84 m2/g and a CO2 capture capacity of 1.05 mmol CO2/g adsorbent compared to L-PEI-PCP. Amongst metal-nanoparticle-embedded PEI-PCPs (M@PEI-PCPs, M: Ni, Co, Cu), Ni@L-PEI-PCP was found to have higher CO2 capture capacity, 0.81 mmol CO2/g adsorbent, and a surface area of 225 m2/g. These data are significant as they will steer future studies for the conversion of captured CO2 into useful fuels/chemicals.

Nitrogen-doped iron-manganese porous carbon particle electrodes for electrocatalytic degradation of tetracycline: Interfacial reaction mechanisms

In this study, nitrogen-doped porous carbon-supported iron-manganese microspheres (FeMn@NC-700) were successfully synthesized and employed as three-dimensional particle electrodes (3DPE) for electro-oxidative of tetracycline (TCH) in water. FeMn@NC-700 exhibited stable catalytic activity and effective TCH removal capabilities under complex water quality conditions and varying pH levels. Under optimized conditions, the 3D/FeMn@NC-700 system reduced the TCH concentration from an initial 20 mg/L to 0.96 mg/L within 60 min, achieving a 95.23 %removal efficiency with an energy consumption of only 10.05 kWh/m3. The outstanding electrocatalytic activity of the 3D/FeMn@NC-700 system was attributed to the dynamic redox cycling between the Fe and Mn species on the 3DPE surface. Radical quenching experiments and electron paramagnetic resonance (EPR) analysis identified the predominant role of singlet oxygen (1O2), effectively removing TCH with the assistance of hydroxyl radicals (·OH) and superoxide anions (O2·-). The degradation pathways of major intermediate products of TCH were proposed, along with a toxicity assessment. In conclusion, the 3D/FeMn@NC-700 system represents a reliable and cost-effective technology for TCH wastewater treatment.

Polyphenol-Based Bicontinuous Porous Spheres Via Amine-Mediated Polymerization-Induced Fusion Assembly.

Bicontinuous porous materials, which possess 3D interconnected network and pore channels facilitating the mass diffusion to the interior of materials, have demonstrated their promising potentials in a large variety of research fields. However, facile construction of such complex and delicate structures is still challenging. Here, an amine-mediated polymerization-induced fusion assembly strategy is reported for synthesizing polyphenol-based bicontinuous porous spheres with various pore structures. Specifically, the fusion of pore-generating template observed by TEM promotes the development of bicontinuous porous networks that are confirmed by 3D reconstruction. Furthermore, the resultant bicontinuous porous carbon particles after pyrolysis, with a diameter of ≈600nm, a high accessible surface area of 359m2g-1, and a large pore size of 40-150nm manifest enhanced performance toward the catalytic degradation of sulfamethazine in water decontamination. The present study expands the toolbox of interfacial tension-solvent-dependent porous spheres while providing new insight into their structure-property relationships.

O-N-S self-doped porous fusiform carbon particles derived from hair for high-performance supercapacitors

O-N-S self-doped porous fusiform carbon particles derived from hair for high-performance supercapacitors

Hierarchical Porous N-Doped Carbon Particles Derived from ZIF-8 as Highly Efficient H2S Selective Oxidation Catalysts.

In the selective oxidation of H2S, the catalytic activity over N-doped carbon-based catalysts is significantly influenced by the accessibility of active sites and the mass transfer rates of reactant molecules (e.g., H2S and O2) as well as generated sulfur monomers. Therefore, it is crucial for enhancing the initial performance via the controlled synthesis of carbon-based catalysts with highly exposed active sites and unique porous structures. Herein, we reported on an efficient strategy to synthesize nanosized N-doped carbon particles with hierarchical porous structures by directly pyrolyzing an oversaturated NaCl-encapsulated ZIF-8 precursor mixture. The introduction of NaCl not only serves as a pollution-free template to promote the formation of graphitic carbon layers but also acts as an intercalating agent to guide the derivation of hierarchical porous structures, as well as enhances the amount of active nitrogen species in the catalysts. As a result, the as-prepared H-NC800 catalyst shows excellent H2S selective oxidation performance (sulfur formation rate is 794 gsulfur·kgcat-1·h-1), good stability (>80 h), and antiwater vapor properties. The characterization results and DFT calculations indicate the crucial role of pyridinic N in the adsorbing and activating reactant molecules (H2S, O2). Furthermore, nanoscale N-doped carbon particles accelerated the rapid transport of generated sulfur monomers under a hierarchical porous structure. This investigation introduces a distinctive strategy for synthesizing ZIF-8-derived N-doped carbon nanosized with a hierarchical porous structure, while its efficient and stable H2S selective oxidation performance highlights significant potential for practical implementation in the industrial desulfurization process.

Facile design and permittivity regulation of porous carbon and magnetic particles based composite nanofibers towards highly efficient electromagnetic wave absorption

Two kinds of porous carbon and magnetic particles-based composite nanofibers (PCNTF-CoFe and PCNTF-NiFe) were synthesized for electromagnetic wave (EMW) absorption. Magnetic particles were used as the catalyst to increase the crystallinity of carbon and the corresponding dielectric loss ability, while porous structure was designed to improve the impedance matching. According to the results, the dielectric loss abilities of PCNTF-CoFe and PCNTF-NiFe are enhanced without significant degradation in their impedance matching condition. Therefore, through the polarization and conduction-induced dielectric loss together with the natural and exchange resonance-induced magnetic loss, the incident EMW can be attenuated rapidly inside PCNTF-CoFe and PCNTF-NiFe. PCNTF-CoFe shows a minimum reflection loss (RLmin) of −54.6 dB and effective band width (RL≤-10 dB, EABW) of 6.0 GHz at 2.0 mm, while PCNTF-NiFe shows RLmin of −33.4 dB and EABW of 5.7 GHz at 1.7 mm. Consequently, PCNTF-CoFe and PCNTF-NiFe can be promising candidates for application in EMW absorption.

Impact of channel nanostructures of porous carbon particles on their catalytic performance.

Mesoporous carbon particles have great potential due to their unique structural properties as support materials for catalytic applications. Particle shapes and channel nanostructures of mesoporous carbon particles can determine the reactant/product transport efficiency. However, the role of the channel nanostructure in the catalytic reaction has not been much explored. Herein, we introduce a facile method to fabricate a series of porous carbon particles (PCPs) with controlled channel exposure on the carbon surface and investigate the impact of the channel nanostructure of the PCPs on the catalytic activity. By employing a membrane emulsification method with a controlled solvent evaporation rate, we fabricate block copolymer (BCP) particles with uniform size and regulated degrees of cylindrical channel exposed to the particle surface. Followed by the carbonization of the BCP particles, a low amount (1.3 wt%) of Pt is incorporated into the PCP series to investigate the impact of channel nanostructures on the catalytic oxidation reaction of o-phenylenediamine (OPD). Specifically, PCP featuring highly open channel nanostructures shows a high reaction rate constant of 0.154 mM-1 s-1 for OPD oxidation, showing 5.5 times higher catalytic activity than those of closed channel nanostructures (0.028 mM-1 s-1). This study provides a deeper understanding of the impact of channel nanostructure within mesoporous carbon particles on catalytic activity.

Nitrogen-Doped Carbon Cubosomes as an Efficient Electrocatalyst with High Accessibility of Internal Active Sites.

Porous carbon particles (PCPs) present considerable potential for applications across a wide range of fields, particularly within the realms of energy and catalysis. The control of their overall morphologies and pore structures has remained a big challenge. Here, using metal-organic frameworks (MOFs) as the precursor and polymer cubosomes (PCs) as the template, nitrogen-doped carbon cubosomes (SP-NCs) with a single primitive bicontinuous architecture are prepared. SP-NCs inherit the high porosity of MOFs, generating a high specific surface area of 825 m2 g-1 and uniformly distributed active sites with a 5.9 at % nitrogen content. Thanks to the presence of three-dimensional continuous mesochannels that enable much higher accessibility of internal active sites over those of their porous counterparts' lack of continuous channels, SP-NCs exhibit superior electrocatalytic performance for oxygen reduction reaction with a half-wave potential of 0.87 V, situating them in the leading level of the reported carbon electrocatalysts. Serving as an air cathode catalyst of the Zn-air battery, SP-NCs exhibit excellent performance, outperforming the commercial Pt/C catalysts.

Corrections to “Morphology Controlled Synthesis of Heteroatom-Doped Spherical Porous Carbon Particles Retaining High Specific Capacitance at High Current Density”

Corrections to “Morphology Controlled Synthesis of Heteroatom-Doped Spherical Porous Carbon Particles Retaining High Specific Capacitance at High Current Density”

Enhancing enantiomeric and diastereomeric separations: A single chromatograph approach for two-dimensional heart-cut methodology

A high-performance chromatograph was adapted and reconfigured to establish a two-dimensional methodology for separations that are not easily achievable using a single enantioselective column. Allethrin, a pyrethroid used widely as a pesticide in domestic environments, was chosen as the model analyte. With three chiral centers, it has eight stereoisomers and is considered one of the more difficult chiral separations. Diastereomeric separation was achieved in the first dimension using a shape-selective stationary phase based on ultrapure porous graphitic carbon (particle diameter, 3 μm) in the reversed phase mode. Advanced asymmetric bidirectional peak functions (half-Gaussian modified Gaussian and exponentially modified Gaussian) were employed to extract overlapping peak areas. The four diastereomeric peaks were heart-cut and sent to the second dimension online using a standard six-port 2-position rotary valve. Enantiomeric separation was attained in the second dimension using an immobilized-cellulose tris(3,5-dichlorophenylcarbamate) column (3 μm) with chromatographic resolutions >2.7 for all enantiomeric pairs. The second dimension method was developed using the information from circular dichroism detection. The baseline separation of seven peaks of allethrin in a single dimension was also demonstrated using (2-hydroxypropyl)-β-cyclodextrin. The enantiomeric purity of a purified formulation of allethrin in a commercial pesticide was validated using the developed 2D approach.

Rational construction of Ni@CBF-x composites derived from bamboo fungus for enhanced microwave absorption with a 10 % filler content

Carbon materials derived from biomass have gained substantial prominence within the domain of microwave absorption (MA). Their eco-friendly attributes, cost-effectiveness, and distinctive morphology have propelled them to the forefront, constituting an effective strategy for the development of sustainable and high-performance microwave absorbing materials (MAMs). Herein, cloud-like porous carbon was derived from bamboo fungus through hydrothermal and carbonization treatment. Subsequently, Ni@carbonized bamboo fungus (Ni@CBF-x) composites were created in situ by introducing magnetic Ni particles. The cloud-like carbon layer derived from bamboo fungus promotes multiple reflections and scattering, enhancing the MA properties of the composites. By adjusting the carbonization temperature, the morphology of Ni particles embedded in the cloud-like porous carbon can be modified, leading to the introduction of numerous heterogeneous interfaces and the construction of 3D conductive networks. Typically, Ni@CBF-800 sample with a filler loading of 10 wt% achieves an impressive minimum reflection loss (RLmin) of –61.2 dB at 10.6 GHz. The effective absorption bandwidth (EAB) of Ni@CBF-1000 sample extends from 6.16 to 11.04 GHz, encompassing 4.88 GHz. Compared to CBF-800 sample, Ni@CBF-1000 sample exhibits a remarkable 171 % increase in EAB, and Ni@CBF-800 exhibits a 50 % increase in RLmin. This exceptional performance can be attributed to four factors, including the strong interfacial polarization induced by the cloud-like porous carbon and Ni particles, the defects created by hydrothermal and carbonization processes, the dipole polarization facilitated by naturally occurring N elements in bamboo fungus, and the magnetic loss caused by magnetic Ni particles. Furthermore, the synergistic coupling of magnetic and dielectric properties serves to optimize the impedance matching characteristics of Ni@CBF-x. These encouraging findings present new avenues for the advancement of magnetic MAMs derived from renewable biomass sources.

Hierarchical Hollow Carbon Particles with Encapsulation of Carbon Nanotubes for High Performance Supercapacitors.

A novel and sustainable carbon-based material, referred to as hollow porous carbon particles encapsulating multi-wall carbon nanotubes (MWCNTs) (CNTs@HPC), is synthesized for use in supercapacitors. The synthesis process involves utilizing LTA zeolite as a rigid template and dopamine hydrochloride (DA) as the carbon source, along with catalytic decomposition of methane (CDM) to simultaneously produce MWCNTs and COx -free H2 . The findings reveal a distinctive hierarchical porous structure, comprising macropores, mesopores, and micropores, resulting in a total specific surface area (SSA) of 913 m2 g-1 . The optimal CNTs@HPC demonstrates a specific capacitance of 306 Fg-1 at a current density of 1 Ag-1 . Moreover, this material demonstrates an electric double-layer capacitor (EDLC) that surpasses conventional capabilities by exhibiting additional pseudocapacitance characteristics. These properties are attributed to redox reactions facilitated by the increased charge density resulting from the attraction of ions to nickel oxides, which is made possible by the material's enhanced hydrophilicity. The heightened hydrophilicity can be attributed to the presence of residual silicon-aluminum elements in CNTs@HPC, a direct outcome of the unique synthesis approach involving nickel phyllosilicate in CDM. As a result of this synthesis strategy, the material possesses excellent conductivity, enabling rapid transportation of electrolyte ions and delivering outstanding capacitive performance.

Phosphorus-doped porous carbon particles based on biomass for efficient adsorption performance of Cu2+ and Zn2+ from aqueous solutions: thermodynamics, isotherms, kinetics, and mechanism

Phosphorus-doped porous carbon particles based on biomass for efficient adsorption performance of Cu2+ and Zn2+ from aqueous solutions: thermodynamics, isotherms, kinetics, and mechanism

Evolution of an Electrochemically Inactive Metal–Organic Framework to Reticulated Porous Carbon Particles with High Supercapacitance

An iron-containing porphyrin-based porous metal–organic framework (PPMOF) has been synthesized and subsequently pyrolyzed to obtain the carbon structure with homogeneous distribution of nitrogen. The pyrolysis is carried out at different temperatures and in the presence of two different environments; in argon to obtain PPMOF-Ar-700, PPMOF-Ar-800, and PPMOF-Ar-900, and in nitrogen to obtain PPMOF-N-800. The motivation here is to study the change in the electrochemical properties that take place on conversion of the metal–organic framework to its corresponding carbons. The materials have been characterized by powder X-ray diffraction, nitrogen adsorption/desorption, scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy, among others. It was observed that PPMOF almost did not show any electrochemical response and was unstable, whereas the carbonized frameworks showed good supercapacitive behavior and stability. The surface area increases from 353 to 838 m2·g–1, when the pyrolysis gas is switched over from nitrogen to argon. It also results in the formation of uniform smooth spherical particles in PPMOF-Ar-800, in contrast to agglomerated broken particles in PPMOF-N-800. PPMOF-Ar-800 shows a remarkable specific capacitance value of 500 F·g–1 at a current density of 1 A·g–1 which is retained at a high value of 111 F·g–1 at a very high current density of 50 A·g–1 in galvanostatic charge/discharge studies, whereas for PPMOF-N-800, the specific capacitance is 400 F·g–1 at 1 A·g–1 and its discharge time is also shorter than that for PPMOF-Ar-800. This indicates that the pyrolysis environment plays a crucial role in the formation and stabilization of the carbon structures.

A microfluidic proton flow reactor system: In-situ visualisation of hydrogen evolution and storage in carbon-based slurry electrodes

A Proton flow reactor (PFR) system stores energy in the form of hydrogen in porous carbon particles in slurry electrodes. However, the hydrogen storage mechanisms and the reactions in this system are not well understood. In this study, we design and fabricate a microfluidic proton flow reactor (MPFR) as a small-scale PFR to enable in-situ visualisation of the key processes underlying PFR operations. We observe the behaviour of slurries and water in both hydrogen and oxygen sides with emphasis on processes in the vicinity of membranes. We use fluorescence microscopy with quinine to visualize hydronium transport from the oxygen to the hydrogen side and employ in-situ Raman spectroscopy to analyze surface structural changes in carbon particles before and after charging. Fluorescence microscopy demonstrates the formation of hydronium ions on the oxygen side and their subsequent migration to the hydrogen side, proving that the oxygen evolution reaction occurs on the oxygen side. Raman heat maps prove the formation of carbon–hydrogen bonding in particles after they are charged with PFR. Although the MPFR is operated at non-optimal slurry concentrations to allow optical access, we demonstrate that it provides maximum hydrogen storage capacity of 0.64 wt%.

Microwave absorption performance of porous carbon particles modified by nickel with different morphologies

• Porous carbon particles (PCPs) derived from flour were successfully prepared. • The nickels with different morphologies were successfully deposited on PCPs. • Only PCPs deposited chain-shaped nickels obtained better performance. • PCPs with chain-shaped nickels showed the best impedance matching. • PCPs with chain-shaped nickels exhibited the strongest loss ability. In this work, porous carbon particles were prepared from wheat flour by pyrolysis and activation. Through the subsequent coprecipitation and electroless plating, the surface and pores of carbon particles were modified by nickel-rich particles with different morphologies. Several loss mechanisms, including dielectric loss, magnetic loss, multiple reflection and scattering loss, were used to assess the attenuation ability to incident electromagnetic waves of these composite particles. The result shows that the chain-shaped morphology of nickel can provide the highest dielectric loss. Under the filler loading of 20 wt.%, the minimum reflection loss (RL min ) reached -38.42 dB at 13.2 GHz, and the maximum effective absorption bandwidth (EAB max ) was 5.2 GHz with a matching thickness of 2 mm. The excellent performance of the composite particles is attributed to the synergistic effect of outstanding impedance matching and superior electromagnetic loss ability caused by the chain structure. The result shows that the morphology of modifiers in carbon-based composites is important to improve microwave absorption performance, and this work provides inspiration for the design of high-performance porous carbon-based composites.

Clarification of the Effects of Oxygen Containing Functional Groups on the Pore Filling Behavior of Discharge Deposits in Lithium–Air Battery Cathodes Using Surface-Modified Carbon Gels

In lithium–air batteries (LABs), controlling the characteristics of the Li2O2 deposited during discharging can lead to the reduction of the large overpotential required for charging. The large overpotential is one of the most significant problems that needs to be solved to improve the cycle performance of LABs. Here, we focused on the effects of functional groups in the cathode carbon on the characteristics of the Li2O2 deposited during discharging and the cathode performance of LABs. In this study, 4 types of carbon gels (CGs) were prepared using different treatment methods to modify their surface properties. The types and amounts of oxygen-containing functional groups (OCFGs) existing within the CGs were clarified along with the number of edge H’s by a high-sensitivity temperature-programmed desorption (TPD) technique. The results of N2 adsorption analysis of discharged CGs suggested that, by increasing the number of OCFGs from 0.40 to 1.80 mmol g–1 through acid treatment, the ratio of Li2O2 deposited within the mesopores of the porous carbon particles can be increased from 1% to 60%. This significant change in the manner of Li2O2 deposition led to the reduction of the charging overpotential. Side reactions that are thought to deteriorate cycle performance tended to proceed in CGs having a large number of OCFGs. This negative effect could be reduced by removing carboxyl groups in the CGs through simple heat treatment at 300 °C in an inert atmosphere. Our study clarified the critical roles of OCFGs in the cathode during the discharging and charging of LABs. The obtained knowledge can be utilized for the development of a high-performance cathode for LABs.

Emulsion‐assisted interfacial polymerization strategy: Controllable architectural engineering of anisotropic and isotropic nanoparticles for high‐performance supercapacitors

AbstractAnisotropic nanoparticles have attracted extensive attention due to their potential applications in material transport, energy storage, and biopharmaceutical. However, due to the inadequate understanding of microscopic particle formation, controllable asymmetric growth is still a great challenge. Herein, we report a facile emulsion‐assisted interfacial polymerization strategy for the synthesis of nitrogen‐doped porous carbon particles (NPCPs) with tunable anisotropic/isotropic architectures. During the synthesis process, we can form emulsion droplets with different nanostructures directionally through dual routes, thereby assisting and mediating the polymerization and growth process of the monomer to obtain poly‐diaminopyridine nanoparticles with various architectures. The corresponding NPCPs with tunable specific surface area (125–362 m2 g−1), nitrogen content (10%–14%), and diverse morphologies can be acquired by calcination under N2 atmosphere at 700 °C. The synergetic effect of abundant microporous structures and active nitrogen species content contributes to improve the physicochemical properties, while the unique anisotropic architecture increases the charge diffusion efficiency and enhances the high‐rate stability. Therefore, the resultant NPCPs electrode exhibits a specific capacitance up to 275 F g−1 at 0.2 A g−1 and surface‐area‐normalized capacitance of 83.0 μF cm−2, indicating a promising material for high‐performance supercapacitors.