Pore Structure Of Carbon Research Articles

Effect of mechanical compaction and nitrogen doping treatment on ultramicropore structure of biomass-based porous carbon and the mechanism of CO2 capture

In the preparation of biomass-derived porous carbon, targeting the enhancement of ultramicropore volume and understanding the effects of nitrogen doping on ultramicroporous structure are crucial for improving CO2 capture. Here, we prepared porous carbon using mechanical compaction and urea-assisted KOH activation of tobacco stem-derived hydrochar. The results showed that mechanical compaction increased the ultramicropore volume with little impact on oxygen content, leading to an increase in CO2 adsorption capacity, with a maximum adsorption capacity of 5.6mmol g−1 at 25℃ and 1 bar. In contrast, nitrogen doping negatively affected the ultramicropore structure and oxygen functionalities, resulting in a decrease in CO2 adsorption capacity. Furthermore, experimental and molecular simulation studies revealed that ultramicropore smaller than 0.5 nm predominantly determine the CO2 adsorption capacity at 0.15 bar and CO2/N2 selectivity. These findings provide theoretical and practical support for the development of efficient carbon-based CO2 adsorbents.

Fully Aqueous‐Processed Li‐Ion Electrodes with Ultra‐High Loading and Potential for Roll‐to‐Roll Processing

In this study, high‐ and ultra‐high‐loading NMC622‐based cathodes (7.0 and 18.0 mAh/cm²) and graphite‐based anodes (9.0 and 22.5 mAh/cm²) were prepared by using a porous carbon structure as current collector. All electrodes in this work were prepared by an NMP‐free, PFAS‐free and scalable process. Full cells with areal capacities of 7 mAh/cm² and 18 mAh/cm² were assembled and tested. The results show an excellent cycling stability, reaching up to 950 cycles at 10 mA/cm² for the cells with ultra‐high‐loading electrodes (capacity 18 mAh/cm²) and 650 cycles at 8 mA/cm² for the cells with high‐loading electrodes (capacity of 7 mAh/cm²). The influence of cathode porosity on the electrochemical performance in cells capacity of 7 mAh/cm² showed that a lower porosity leads to a poorer rate capability as well as a worse cycling capability (400 cycles at 6 mA/cm²). Post‐mortem analysis reveal that the anode aging is more pronounced during full cell cycling. Further the scalability of the production process was demonstrated by using a padder tool. With that, cathodes with a loading of 5 mAh/cm² were produced in a roll‐to‐roll process.

3D Graphene-Like Carbon Structures from Poly(Acrylic Acid): A Novel Synthetic Route.

Emerging contaminants, such as the hormone 17α-ethynylestradiol (EE), in aquatic environments pose a serious risk to both human and environmental health, making efficient removal essential. This study evaluated the effectiveness of three-dimensional porous carbon structures derived from poly(acrylic acid) (PAAc, Carbopol 990) as adsorbents for removing EE from aqueous solutions. Activated carbon materials were prepared using varying ratios of KOH as an activating agent (PAAc : KOH; 1 : 0 AAC, 1 : 1 AC1, 1 : 2 AC2, and 1 : 3 AC3). Adsorption tests were conducted by adding 10 mg of the adsorbent to 40 mL of an EE solution (100 ppm, 20 % acetonitrile in water). Analyses including TGA, XRD, and Raman spectroscopy were performed to evaluate the materials' structural properties and adsorption capacities. Among the materials, AC3 exhibited the highest adsorption capacity for EE (238 mg g-1), followed by AC2 (153 mg g-1) and AC1 (82 mg g-1). The superior efficiency of AC3 can be attributed to its larger surface area and pore volume, enabling greater interaction with EE molecules. These materials demonstrated higher adsorption capacities compared to commercial activated carbons and single-walled carbon nanotubes. This work opens new possibilities for developing efficient adsorbents, contributing to more effective and sustainable solutions for water purification and environmental protection.

Hybrid Particle Size Template Method for Controllable Synthesis of Nitrogen-Doped Multilevel Porous Carbon as High-Rate Zn-Ion Hybrid Supercapacitor Cathode Materials.

Achieving high rate performance without compromising energy density has always been a critical objective for zinc-ion hybrid supercapacitors (ZHSCs). The pore structure and surface properties of carbon cathode materials play a crucial role. We propose utilizing a hybrid particle size (20 and 40 nm) magnesium oxide templates to regulate the pore structure of nitrogen-doped porous carbon derived from the soybean isolate. The multilevel pore structure enhanced ion transport efficiency while also improving the utilization of micropores. Nitrogen doping and oxygen-containing functional groups enhanced the wettability of carbon materials with aqueous electrolytes and facilitated the chemisorption of Zn2+ on the carbon material surface. The nitrogen-doped multilevel porous carbon material (HT-NMPC-1/1) prepared with a 1 : 1 mass ratio of the two templates exhibited a specific capacity of 146.65 mAh g-1 at 0.2 A g-1. Moreover, the Swagelok cells assembled with HT-NMPC-1/1 and Zn foil achieved a high energy density of 121.5 W h kg-1, high power output of 166 W kg-1, and 93.09 % capacity retention after 8000 cycles at 2 A g-1. Therefore, HT-NMPC-1/1 is a highly promising candidate for ZHSCs cathode materials. Furthermore, the novel pore regulation strategy and straightforward preparation method offer valuable reference points for other porous carbon-based functional materials.

Rational engineering of meso-macroporous structured carbon materials for revealing capacitive mechanism

The tailorable meso-macroporous structure of hierarchical porous carbon (HPC) is an essential key to improve ion diffusion dynamics and microporous accessibility for capacitive material. However, few studies focus on the capacitive mechanism of meso-macroporous proportion of HPC. Herein, a regionally selective dissolution and pyrolysis strategies are deployed to tailor the proportion of meso-macropores in facial mask-derived HPC through adjusting the oxalic acid concentration in hydrothermal process in this contribution. The obtained HPC show increasing meso-macroporous volumes of 0.04, 0.12, and 0.40 cm3 g−1, corresponding to the oxalic acid concentrations of 0.2, 0.5, and 1.0 g/50 ml, respectively, while the microporous structures remain similar. Electrochemical results show that with increasing proportion of meso-macropores, the specific capacitances of HPC decrease from 386.9 to 276.5 and 220.3 F g−1 at current density of 1 A g−1, and decrease from 216.7 to 181.1, and 133.1 F g−1 at 50 A g−1. CV fitting results indicate that a small number of meso-macropores can enhance the surface-controlled capacitive contribution, improving the accessibility of micropores and faradaic pseudocapacitive reactions. The optimized HPC-based supercapacitor delivers a high energy density of 11.5 Wh kg−1 at a power density of 125 W kg−1 in KOH electrolyte and a maximum energy density of 49.4 Wh kg−1 at 225 W kg−1 in Na2SO4 electrolyte with long cycle stability, suggesting that the rational engineering of meso-macroporous proportion in HPC uncover news insights into developing high performance supercapacitor.

Construction of Microporous Structure in Hard Carbon via Adjustable Zn Salt Templates for High-Performance Sodium-Ion Batteries

Template method is an effective strategy for the construction of microporous structure in hard carbons. However, the introduction of templates will inevitably affect the original structure of hard carbon, making it necessary to develop an adjustable template for the high sodium storage property of Sodium-ion battery anodes. Herein, we propose an effective strategy of developing size-controlled ZnO microcrystal in precursor carbon by zinc salts templates and promoting the formation of numerous closed pores during subsequent pyrolysis. All of the obtained hard carbons exhibit high specific capacities of over 340 mAh/g, and initial Coulomb efficiencies of over 90%. Besides, the information of closed pore structure in hard carbon, accompanying with the diffusive behavior of Na+ and the in-situ Raman spectroscopy reveal a strong link between the increased plateau and the closed pore volume, providing a compelling insight for the mechanism of Na+ storage in hard carbon. The optimal sample exhibits the highest closed pore volume, which performs a remarkable specific capacity of 374 mAh/g and a high initial Coulombic efficiency of 92.4%. Furthermore, all zinc salt-derived hard carbon exhibit analogous microstructures and electrochemical behaviors, demonstrating the universality of utilizing both inorganic and organic zinc salts as templates for adjusting the microporous structure of hard carbon. These findings provide a systematic approach to enhance the reversible capacity and maintain high initial Coulombic efficiency for sodium-ion battery anodes.

Magnesium Bicarbonate-Walnut Shell Dual-Template Synthesis of Multifunctional Layered Porous Carbon for Enhanced Adsorption of Aqueous Chlorinated Organic Compounds.

Chloride ions readily react with organic matter and other ions, resulting in the formation of disinfection by-products (DBPs) that exhibit heightened levels of toxicity, carcinogenicity, and mutagenicity. This study creatively employed waste walnut shells as self-templates and low-cost magnesium bicarbonate as a rigid template to successfully synthesize multifunctional porous carbon derived from walnut shells. Employing a series of characterization techniques, it was ascertained that the porous carbon material (WSC/Mg) synthesized via the dual-template method exhibited a distinct layered microscopic surface structure, with a predominance of C and O elements on the surface. The material displayed a high degree of graphitization, significant specific surface area, and abundant oxygen-containing surface functional groups. The incorporation of magnesium bicarbonate as a hard template improved the structure of the walnut shell porous carbon, resulting in a significant enhancement in mass transfer efficiency for the target product on the adsorbent and a substantial improvement in removal efficiency. In comparison with walnut shell-derived carbon using only self-templating, WSC/Mg exhibited a 17.26-fold increase in adsorption capacity for 2,4-dichlorophenol. Furthermore, even after four adsorption-desorption cycles, WSC/Mg-12 maintained an adsorption efficiency above 90%. It is remarkable that WSC/Mg-12 demonstrated exceptional resistance to interference from natural organic matter and pH variations. Moreover, the adsorbed saturated WSC/Mg-12 effectively treated real coke wastewater, resulting in an 80% color removal rate, 20% COD removal rate, and 15% ammonia nitrogen removal rate. In conclusion, this study presents an innovative approach for cost-effective and versatile porous carbon materials with extensive applications in water environment purification and biomass utilization.

Magnetic Fe3O4 nanoparticles supported on carbonized corncob as heterogeneous Fenton catalyst for efficient degradation of methyl orange

The pollution especially organic dyes pollution of water resources is an urgent issue to be solved. It is crucial to develop highly efficient, low cost and recyclable heterogeneous catalysts for wastewater treatment. In this study, a heterogeneous Fenton catalyst loaded with Fe3O4 nanoparticles was prepared by one step pyrolysis using natural crop waste corncob as carbon source. The prepared porous carbon catalyst can effectively degrade methyl orange (MO, 25 mg·L−1) at room temperature, and the degradation rate is 99.7%. In addition to high catalytic degradation activity, the layered porous carbon structure of the catalyst also provides high stability and reusability. The degradation rate can be maintained above 93% after 10 cycles. Furthermore, the prepared catalyst is magnetic, which makes the catalyst easy to recycle in practical applications. In addition, the prepared Fe3O4/RCC catalyst has efficient Fenton degradation activity for bisphenol A (BPA) (96.9%) and antibiotic tetracycline hydrochloride (TC-HCl) (95.5%), which proves that it has universal applicability for the degradation of most organic pollutants. This study provides a feasible and scalable strategy to prepare a heterogeneous Fenton catalyst treating wastewater and high-value utilization of biomass waste.

In-situ formation of La2O2CO3 uniformly immobilized on biomass-derived carbon aerogel for enhanced phosphate removal

In the face of the dual pressures of eutrophication and phosphorus shortages, it is of utmost importance to efficiently remove and recover phosphate from wastewater. In this study, waste-biomass-derived carbon aerogel (CA) was utilized as a dispersing carrier for lanthanum (La), resulting in the successful in-situ generation of an La2O2CO3 (La3.5-CA-450) phosphate adsorbent on the CA matrix. The results demonstrated that the introduction of CA as an adsorbent led to abundant carbon defects and pore structures, which significantly enhanced its performance. Moreover, through the coordinated pyrolysis of CA and La3+, CO32−, capable of exchanging with PO43−, was generated, thereby contributing to the exceptional phosphate adsorption capacity exhibited by the adsorbent. Specifically, La3.5-CA-450 displayed a high phosphate adsorption capacity of 155.8 mg P/g (272.4 mg P/g La), with the molar ratio of P to La being 1.22:1, indicating a high utilization efficiency for La. The adsorbent exhibited exceptional performances in terms of selectivity, renewability, efficient use in natural water environments, and robust application in a broad range of synthetic availability. This research adheres to the green concept “using waste to treat waste” while providing a novel approach for preparing efficient La-based phosphate adsorbents.

Sustainable pseudocapacitance potential of a hybrid triad involving activated carbon derived from polyester wastes

This study introduces an innovative approach to fabricate high-efficiency supercapacitor electrodes by utilizing waste polyester (PES), a common fabric waste, as a precursor for producing activated carbon. This approach not only addresses waste disposal issues but also provides a valuable resource for various environmental and industrial applications. Through a series of chemical and thermal treatments, PES waste is transformed into a porous carbon structure, which is then functionalized with PPy and V2O5 to enhance its electrical conductivity and electrochemical performance. The synthesized composite is characterized by several analytical and spectral techniques to elucidate the morphological, structural and surface properties. The specific surface area of the hybrid composite material is 50.4 m2g−1. Cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy are employed to evaluate the performance of the composites as supercapacitor electrodes. From the CV curves, the electrochemically active surface area was calculated to be 0.085 m2g-1. The composite exhibits a remarkable specific capacitance of 535 Fg-1 and energy as well as power density values of 171 W h Kg−1 and 2877 W Kg−1 respectively at a current density of 2 Ag−1. The material was fabricated into device and was observed to show excellent cycling satbility for up to 10,000 cycles.

Supermolecule-opitimized defect engineering of rich nitrogen-doped porous carbons for advanced zinc-ion hybrid capacitors.

Pitch-based porous carbons with adjustable surface chemical property and controllable pore structure are regarded as promising cathode materials for aqueous zinc-ion hybrid capacitors (ZIHCs), while its disordered carbon matrix and microstructure as well as insufficient surface defects often result in low Zn2+-storage capacity and poor rate capability of ZIHCs. Herein, a synergetic strategy of self-assembled supermolecule and enriched defective carbon engineering was developed to achieve ultrahigh edge-nitrogen doping for ZIHCs. The crystallite defects and surface structure of porous carbon could be effectively achieved through grafting electronegative oxygen-containing small molecules and high-level nitrogen-containing functional groups between modified polycyclic aromatic hydrocarbon and supermolecule framework. The optimized three-dimensional carbon structure delivered high capacity of 218 mAh g-1 at 0.2 A g-1, fast charge/discharge capability, enhanced energy density (165.4 Wh kg-1) and superior cycling stability (95% retention after 10000 cycles as cathode of ZIHCs). This provided new insight into the controllable synthesis of carbon cathodes for ZIHCs and expects to prepare functional porous carbon by supermolecules and special precursors.

Incorporation of Mo2C nanoparticles to pollen-derived 3D porous carbon as electrocatalyst for high performance lithium-sulfur batteries

The practical application and development of lithium‑sulfur (LiS) batteries are limited by the slow redox reaction kinetics and shuttle effect of polysulfide lithium (LiPSs). To address these issues, three-dimensional porous carbon (PC, derived from rapeseed pollen) modified with molybdenum carbide (Mo2C) nanoparticles is prepared by a simple and environment-friendly method. On the one hand, the PC-Mo2C host material can facilitate the uniform loading of sulfur and reduce its volume expansion due to its porous carbon structure. On the other hand, it mitigates the shuttle effect by effective chemical adsorption of LiPSs to form strong physical confinement and catalyze the conversion of LiPSs via the aid of the decorated Mo2C nanoparticles. Density functional theoretical calculations also illustrate the Mo2C nanoparticles are capable of inhibiting the shuttle of LiPSs and further improving the cycling stability. The results show that the PC-Mo2C/S electrode exhibits excellent electrochemical performance with high cycle stability (fading rate of 0.066 % per cycle at 0.2C and 0.054 % per cycle at 1C) and outstanding rate capacity (623.2 mAh g−1 at 5C).

Nitrogen-doped porous carbon nanosheets derived from furfural residue as an oxygen reduction catalyst

The complex pore structure of porous carbon plays a pivotal role in determining the catalytic activity of catalysts involved in the oxygen reduction reaction (ORR), and template methods have emerged as the gold standard in the fabrication of porous carbon. This study describes the preparation of a series of carbon materials that use furfural residue and urea as carbon and nitrogen sources, respectively, in conjunction with KOH as an activating agent through a template method. The prepared catalysts have a large specific surface area and an abundance of micro/mesoporous structures, both of which facilitate ion transport and promote active site exposure. Notably, the sample with a carbon-to-nitrogen mass ratio of 1:4 (FR/C-4) exhibits an exceptionally high specific surface area (2190 m2 g−1) along with an impressive array of pore structures. Compared with commercial Pt/C, FR/C-4 demonstrates superior ORR catalytic activity with a half-wave potential (E1/2) of 0.88 V. Furthermore, FR/C-4 demonstrates remarkable stability and methanol tolerance in alkaline electrolytes, indicating its potential for a wide range of applications, such as fuel cells and metalair batteries.

Preparation of highly graphitized porous carbon and its ethane/ethylene separation performance

The efficient separation of ethane (C2H6) and ethylene (C2H4) is crucial for the preparation of polymer-grade C2H4, necessitating the development of highly selective and stable C2H6/C2H4 adsorbents. Highly graphitized porous carbon, denoted GC-800, was synthesized by polymerization at room temperature followed by carbonization at 800 °C using phenolic resin as the precursor and FeCl3 as the iron source. Vienna Ab-initio Simulation Package (VASP) calculations confirmed a higher binding energy between C2H6 molecules and graphitized porous carbon surfaces, so that a high degree of graphitization increased the adsorption capacity of porous carbon for C2H6. However, catalytic graphitization using Fe at high temperatures disrupted the microporous structure of the carbon, thereby reducing its ability to separate C2H6/C2H4. By controlling the carbonization temperature, the degree of graphitization and pore structure of the porous carbon could be changed. Raman spectra and XPS spectra showed that the GC-800 had a high degree of graphitization, with a sp2 C content as high as 73%. Low-temperature N2 physical adsorption measurements estimated the specific surface area of GC-800 to be as high as 574 m2·g−1. At 298 K and 1 bar, it had an equilibrium adsorption capacity of 2.16 mmol·g−1 for C2H6, with the C2H6/C2H4 (1:1 and 1:9, v/v) ideal adsorbed solution theory selectivity respectively reaching 2.4 and 3.8, significantly higher than the values of most reported high-performance C2H6 selective adsorbents. Dynamic breakthrough experiments showed that GC-800 could produce high-purity C2H4 in a single step from a mixture of C2H6 and C2H4. Dynamic cycling tests confirmed its good cyclic stability, and that it could efficiently separate C2H6/C2H4 even under humid conditions.

Pyrolytic conversion of cattle manure into value-added products and application of biochar for adsorption of sulfamethoxazole

This study investigated the thermochemical conversion of cattle manure (CM) to propose a sustainable platform for its valorization, and explored the applicability of CM-derived biochar (CMB) as an environmental medium for the adsorptive removal of sulfamethoxazole (SMZ). CM pyrolysis was conducted under two atmospheric conditions (N2 and CO2), and the pyrogenic products were quantified and characterized. Real-time syngas monitoring revealed that CO2 enhanced CO generation from the CM, leading to the formation of a highly porous carbon structure in the produced biochar (CMBCO2). The adsorptive removal of SMZ by CMBCO2 was highly dependent on the pH conditions. The adsorption kinetics of SMZ onto CMBCO2 reached equilibrium within 540 min, following a pseudo-second-order model. The SMZ adsorption isotherms fit the Langmuir-Freundlich model, highlighting the importance of chemisorption in the adsorption process. X-ray photoelectron spectroscopy revealed that SMZ was adsorbed by non-electrostatic mechanisms, including hydrogen bonding, Lewis acid-base interactions, surface complexation, and π–π electron-donor acceptor interactions. This study presents an exemplary strategy for converting livestock waste into valuable resources, enabling the harvesting of energy resources and the production of treatment media for environmental remediation.

Preparation of pistachio shell-based porous carbon and its adsorption performance for low concentration CO2

In this study, high-performance porous carbon for CO2 adsorption was synthesized from pistachio shells and modified with urea to enrich nitrogen content in the porous structure. The effects of activation temperature, KOH-to-carbon ratio, and urea addition on the pore structure and CO2 adsorption capacity of the porous carbon were investigated. Characterization was conducted using N2 adsorption-desorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). Results showed that under preparation conditions of 700 °C, KOH-to-carbon ratio of 2, and 15 wt% urea concentration, the synthesized GAC-15-2-700 porous carbon exhibited a maximum specific surface area of 1395 m2/g, micropore volume of 0.505 cm3/g, and N-5 peak area ratio of 65.57%. It achieved a CO2 adsorption capacity of 3.56 mmol/g. Nitrogen functional groups on the porous carbon primarily existed as pyridinic N (N-6), pyrrolic/pyridinic N (N-5), and quaternary N (N-Q), with the enriched micropores and high N-5 content being crucial for CO2 adsorption.

Superior Electrochemical Sensor Application of Co3O4/C Heterostructure in Rapid Analysis of Anticancer Drug Palbociclib in Pharmaceutical Formulations and Biological Fluids.

In this work, we report a study examining how different salt concentrations affect the structure and electrochemical performance of two Co3O4/C materials designed for the fabrication of an easy, cheap, fast, safe, and useful electrochemical sensor for the detection of Palbociclib (PLB). Co3O4 nanoparticles were successfully created by encapsulating them in N-doped amorphous carbon matrices by using the molten salt-assisted approach. In this process, different amounts of potassium iodate and zeolitic imidazolate framework-12 (ZIF-12) were used, followed by pyrolysis at 800 °C. Optimum Co3O4 embedded porous carbon structures were obtained, and the composite with the highest electrochemical properties was modified to a glassy carbon electrode (GCE) surface for PLB detection. The linear response spanned from 1.0 to 5.0 μM, featuring a limit of detection (LOD) of 0.122 μM and a limit of quantification (LOQ) of 0.408 μM; the correlation coefficient was calculated as 0.995. The high sensitivity of the method in detecting PLB in pharmaceutical samples and human urine demonstrated its feasibility, with recovery percentages ranging from 99.3% to 101.3% and relative standard deviation (RSD) values of <3%. Therefore, this technique will make a significant contribution to monitoring and improving existing cancer treatment options.

Lightweight composites derived from carbonized taro stems for microwave energy attenuation and thermal energy storage

A novel strategy has been developed for preparing porous carbon materials derived from taro stems, aimed at enhancing electromagnetic wave (EMW) attenuation and thermal energy storage. The materials were synthesized through the carbonization of taro stems to form a porous carbon structure, subsequently enhanced with polyethylene glycol (PEG) containing carbon nanotubes (CNTs) and nickel (Ni) nanoparticles. By adjusting the carbonization temperature and the loading of CNTs and Ni, the resulting carbon materials exhibited exceptional EMW attenuation performance. Specifically, the PC-800 sample demonstrated a remarkable minimum reflection loss of −61.4 dB across the frequency range of 8.2–11 GHz, with a low density of 0.054 g/cm³. The PC-1200 sample exhibited EMI SE values of 23.6 dB axially and 21.5 dB radially in the X-band, with an ultra-low density of 0.033 g/cm³. Further enhancements were observed in the PC/CNT2 and PC/CNT2-Ni15 composites, achieving EMI SE values of 26.3 dB and 26.8 dB, respectively. Additionally, these composites exhibited effective thermal energy storage and release, as confirmed by heating experiments. This study not only introduces a method for creating absorption-dominated biomass electromagnetic shielding materials but also provides a dual-functional solution for enhancing the performance of electronic devices.

Etching physicochemical adsorption sites of biochar by steam for enhanced hydrogen storage

Enhancing the hydrogen storage capacity of carbon-based materials requires the precise synthesis of strong hydrogen adsorption sites. Consequently, this work suggests improving hydrogen storage capacity by employing H2O low-temperature etching technology. First, the simulation methods investigated the pore structure and oxygen-containing groups’ adsorption properties on hydrogen. The results showed that the oxygen-containing group could increase the adsorption energy of biochar on hydrogen, and the carboxyl group had the greatest effect. A suitable coupling of pores and oxygen-containing groups can improve the microporous region’s hydrogen storage capacity. Moreover, biochar may form a new ultra-microporous region (less than 0.5 nm) by etching it at 700 °C and 30 vol% H2O. After etching 90 min, the surface oxygen concentration remained stable at 14 at.%. In conjunction with results from mass spectrometry, we discovered that the process influencing pore growth was the heterogeneous interaction between CO and H2 to create CH4. At 25 ℃ and −196 ℃, the KSBC-30–60 showed superior hydrogen storage capacity compared to KSB. Its total adsorption capacity was 0.49 wt% and 5.28 wt%, respectively, and increased by 1.32 and 1.2 times. This study proposes a novel approach to improving hydrogen storage by etching porous carbon structures with H2O. The strategy has the potential for large-scale application and can be further utilized in the design and optimization of related carbon adsorbents.

Spectroelectrochemical study of carbon structural and functionality characteristics on vanadium redox reactions for flow batteries.

Vanadium redox flow batteries have applications for large-scale electricity storage. This paper reports the influence of carbon structural characteristics of sustainable walnut shell-derived carbons in carbon/polyvinylidene fluoride composite electrodes on vanadium redox reactions. Pyrolysis, gasification, and chemical treatment procedures were used to modify the structural characteristics of carbons. Carbon functional groups were modified by chemical treatment with HNO3, heat treatment with K2CO3, and high-temperature NH3 treatment. Carbon porous structures were characterized using gas adsorption studies. Raman spectroscopy and X-ray diffraction were used to characterize the carbon molecular structure. Functional groups were characterized using X-ray photoelectron spectroscopy, acid/base titrations, temperature-programmed desorption, and Fourier transform infrared spectroscopy. The influence of carbon structure, porosity, and surface functional groups on the redox reactions of vanadium was investigated using cyclic voltammetry and electrical impedance spectroscopy. The VO2+/VO2 + and V2+/V3+ couples had well-defined peaks in cyclic voltammetry, with the former being the most intense, but the V3+/VO2+ couple was not observed for samples carbonized under nitrogen. The results show that V2+/V3+ and VO2+/VO2 + couples observed in cyclic voltammograms were enhanced for carbonization temperatures up to 800 °C. Electrical impedance spectroscopy also showed impedance trends. The electrochemistry results are primarily related to changes in carbon structure and the catalysis of V3+ oxidation by surface functional groups in the carbon structure. The V3+/VO2+ couple was limited by slow kinetics, but it occurs on specific oxygen and nitrogen sites in the carbon structure. The oxidation of V(iii) to V(iv) only occurs on a limited number of surface sites, and the outer-sphere electron transfer to oxidize V(iii) takes place at much more positive potentials. The coulombic, voltage, and energy efficiency of the carbon electrodes were suitable for batteries.