Carbon Materials Research Articles

Synthesis and Characterisation of Porous Carbide-derived Carbon from SiC in Molten Salt

Aims: In this paper, we aimed to prepare SiC-CDC with porous structure from SiC precursor by using simple molten salt electrochemical etching method at 900 ºC in argon at an applied constant voltage of 3.0 V. Background: Nanoporous materials include carbon materials, silica or alumina, gel, and zeolite, which have been known since ancient times. Among all these materials, carbon materials are particularly outstanding. In recent years, carbide-derived carbon (CDC), a type of unconventional carbon material produced by selectively extracting metal elements from the lattice of carbides, has attracted increasing attention from researchers. Many different methods have now been proposed to prepare CDC, among these methods, currently the preparation of mesoporous carbide-derived carbon (CDCs) materials mainly relies on chlorination. The main problems with chlorination are the corrosion of chlorine gas and the treatment of secondary products (MClx). Therefore, the search for environmentally friendly strategies for the production of CDC is still ongoing. Objective: This article proves that we can successfully prepare SiC-CDC with porous structure from SiC precursor by using simple molten salt electrochemical etching method at 900ºC in argon at an applied constant voltage of 3.0 V. Methods: The SiC-CDC with porous structure has been prepared from SiC precursor by using simple molten salt electrochemical etching method at 900ºC in argon at an applied constant voltage of 3.0 V. Results: The results show that the nanoporous SiC-CDC was successfully synthesized from the silicon carbide microspheres powder via by electrolysis in molten CaCl2 at 3.0 V, 900°C for 15 h. Conclusions: The nanoporous SiC-CDC was successfully synthesized from the silicon carbide microspheres powder via by electrolysis in molten CaCl2 at 3.0 V, 900°C for 15 h and their microstructure, specifc surface area, and pore size were analyzed. The SiCCDC obtained in this experiment mainly consisted of amorphous carbon and maintained the shape of SiC particles. The SiC-CDC is a mixture of amorphous carbon and ordered graphite phase with a highly degree of graphitization. The SiC-CDC displays a BET specific surface area of 561.39 m2/g and a total pore volume of 0.39 cm3/g. This method to produce SiC-CDC is very attractive because it will not only pave a new way for the preparation of SiC-CDC but also for mass production of high-quality carbon material.

Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights

Effective surface functionalization of carbon nanomaterials plays a crucial role in various applications. We investigated the impact of edges on surface functionalization and stability of oxygen-modified carbon materials using a combination of experimental techniques and Density Functional Theory (DFT) insights. Graphenic paper, highly oriented pyrolytic graphite (HOPG), and graphenic flakes were employed as model systems, with oxygen plasma treatment (generator power 100 W, oxygen pressure 0.2 mbar, exposure time 6 – 300 s) serving as the modification method. Surface morphology and chemical composition were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The results revealed the introduction of oxygen functional groups on the investigated carbon surfaces (up to 20 at % by XPS) whereas; the structural integrity of the materials remained intact upon plasma modification (SEM, Raman). Work function was used as a sensitive parameter for monitoring the surface changes (increase by ∼1.4 eV, 1.3 eV, and 1 eV for graphenic paper, HOPG, and graphenic flakes, respectively) while time-dependent measurements revealed distinct kinetic processes governing the decay of functionalization, highlighting the role of surface defects in post-plasma processes. DFT calculations provided molecular-level insights into the surface processes, elucidating the mechanisms underlying the diffusion of hydroxyls, their recombination, and water desorption. Since the calculated activation barrier for recombination on basal graphenic planes (∼1.0 eV) and edges (∼5.5 eV) are distinctly different, it can be thus concluded that the persistent functionalization is due to the surface edges. Our findings contribute to a deeper understanding of surface modification processes of carbon materials and offer rationales for the design of advanced functional nanomaterials with tailored surface properties.

Improving energy storage ability of nickel and cobalt hydroxides coupled with reduced graphene oxide via incorporating novel structure-directing agents for supercapacitors

Zeolitic imidazolate framework 67 (ZIF67) derivatives are regarded as potential active materials for energy storage, owing to the possible enhancement on electrical conductivity and maintenance of high surface area and tunable pore structure. However, current improvements on electrical and physical properties of ZIF67 derivatives are still insufficient to achieve excellent energy storage abilities. In this study, new types of carbon material and structure-directing agents (SDA) are incorporated into the synthesis of ZIF67 derivatives to enhance electrical conductivity and modulate morphology. Commercial reduced graphene oxide (rGO), NH4BF4 and NH4HF2 are applied as the carbon material and SDAs, respectively. With the optimal rGO ratio, the rGO/ZIF67 derivative electrode exhibits a higher specific capacitance (CF) of 1304.7 F/g (913.0C/g) at 20 mV/s, while the ZIF67 derivative electrode without rGO shows a CF value of 786.9 F/g (550.8C/g). The supercapacitor composed of the optimal rGO/ZIF67 derivative and rGO electrodes presents a maximum energy density of 30.2 Wh/kg at 350 W/kg. The Coulombic efficiency of 93.0 % and CF retention of 86.5 % are achieved for the device after 10,000 cycles. The novel carbon material and SDAs are expected to be applicable in more electrochemical systems to achieve better energy storage ability.

Green preparation of carbon materials from biomass slag and steam as byproducts of power plants for efficient treatment of lead-containing wastewater

Green preparation of high-performance and cost-effective carbon materials using biomass slag and steam, which were the byproducts of power plants, for efficient treatment of lead (Pb(II))-containing wastewater was investigated. The optimum carbon material CH500-800 (SBET=818.8 m2/g and Vt=0.46 cm3/g) was produced by one-step steam activation at 800 ℃ for 1h under a 500mL/min stream with a heating rate of 5°C/min. The obtained CH500-800 greatly enhanced the efficiency of Pb(II) removal, achieving the maximum adsorption capacity of 191.1mg/g. The removal of Pb(II) from wastewater was well described by the Pseudo-second-order, Elovich and Freundlich model, suggesting that it was predominantly governed by chemical adsorption and diffusion on heterogeneous surfaces. The adsorption process demonstrated a synergistic mechanism involving pore and surface adsorption, chemical interactions between oxygen-containing groups (C-O and -OH) and Pb(II), as well as Pb(II)-π interactions, which was responsible for the efficient removal of Pb(II) from wastewater. Moreover, CH500-800 retained a potential for reusability with a high adsorption stability (only 2.5% Pb(II) desorption after 48h) and ion selectivity (>93.0%) in the presence of K(I), Na(I) or Ca(II). Additionally, a circular economic model was proposed to valorize biomass slag and steam in situ for treating Pb(II)-containing wastewater effectively in biomass power plants. This approach provided an innovative solution for utilizing waste to treat hazardous substances within practical engineering applications.

Efficient degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe-N co-doped carbon materials: Singlet oxygen and electron-transfer mechanisms

Singlet oxygen (1O2) is widely recognized as an effective reactive species for the targeted oxidation of organic contaminants. However, producing 1O2 with high selectivity and efficiency remains a significant challenge. This study describes the synthesis of a N-C-loaded Fe catalyst (Fe/NC) loaded with nitrogen-doped carbon materials. The Fe/NC catalyst efficiently produces 1O2 via the activation of peroxymonosulfate (PMS), demonstrating exceptional degradation capabilities for p-chlorophenol (4-CP). Compared to the control samples of nitrogen-doped carbon (NC) and Fe/NC-x under identical conditions, the Fe/NC/PMS produced a significantly greater degradation rate (0.794min-1) for 4-CP (50mg⋅L-1) within 14min. The content of zinc was regulated to enhance the degradation of 4-CP. The durability of the catalyst was tested with a fixed-bed flow reactor, maintaining almost 100% removal efficiency over 36h on stream. The 4-CP degradation within this system was shown to be a non-radical process predominated by 1O2 and electron transfer, as shown by electrochemical methods, quenching studies, and electron paramagnetic resonance test (EPR). Moreover, Fe/NC demonstrated exceptional resistance to pH changes (3-10), natural organics, and inorganic ions while degrading organic contaminants. The degradation process of 4-CP over the Fe/NC catalyst was examined using liquid chromatography-mass spectrometer. The results of the phytotoxicity evaluation indicated a significant decrease in their toxicity within the Fe/NC/PMS/4-CP system. The satisfactory activity, stability, and universality enabled Fe/NC to serve as a promising candidate for PMS activation. This study presents a novel approach for the selective production of 1O2, enabling targeted pollutant degradation in wastewater treatment.

Synthesis of activated carbon from sugarcane bagasse using blends of hydroxides for maximizing reaction targeted at obtaining hydrogen peroxide

This study investigates the potential reutilization of sugarcane bagasse (SCB) – a highly abundant residue generated from the sugar and ethanol industries. Activated carbon (AC) with optimized selectivity toward hydrogen peroxide (H2O2) electrogeneration was obtained by applying a customized process that involved the impregnation of the residue with KOH and NaOH and thermal activation. To optimize the properties of the AC, the following synthesis parameters were evaluated: proportion of KOH/NaOH used in the impregnation process, activation temperature, holding time (of the activation temperature), and concentration of activating solution. The optimized condition obtained was NaOH at 10 %m/v, activation temperature of 650 ºC, and holding time of 60 min; this condition was found to be more sustainable than that of the traditional processes employed in obtaining black carbon. The near-optimal condition generated an AC with outstanding wettability, high amount of oxygenated groups on the surface, and a surface area of 121.2 m2 g-1, with good theoretical selectivity toward H2O2 electrogeneration (90 % at -0.4 vs. RHE) and an onset potential of +0.3 vs RHE. Our findings show that the SCB-derived AC material could be used as an environmentally friendly and economical alternative to conventional petroleum-derived carbon materials commonly used in H2O2 electrogeneration and as a support material for other active materials. The study shows that the precise equilibrium of the physical attributes of the carbon material and the chemical composition of its surface, influenced by the activation process, are key factors that affect catalytic efficiency in the in situ electrogeneration of H2O2.

Molten Salt Activation Combined with In-situ Surface Graphitization towards Wood-Derived Self-Supporting Carbon Electrodes with High Volumetric Specific Capacity for Zinc-Ion Hybrid Supercapacitors

Despite significant advancements in enhancing the gravimetric and areal specific capacities of carbon electrodes for zinc-ion hybrid supercapacitors (ZHSCs), the attainment of a high volumetric specific capacity remains a pivotal challenge. This research suggests an innovative method to boost the volumetric specific capacity of carbon electrodes by constructing self-supporting carbon electrodes derived from wood. The process involves a synergistic application of molten salt activation and in-situ surface graphitization. Specifically, pine wood (Pinus sylvestris var. mongolica Litv.) undergoes initial carbonization, followed by treatment with a molten salt electrolyte, generating a carbon material distinguished by a penetrating channel structure, a rich micro-mesoporous network, and distinct characteristics such as self-support and surface graphitization. These qualities contribute to a significant increase in the volumetric specific capacity of the resultant carbon electrode, achieving up to 26.3 mAh cm–3 at 2mAcm–2, surpassing commercial activated carbon and analogous materials in ZHSC applications. Additionally, a coin-cell ZHSC utilizing this innovative carbon electrode demonstrates exceptional performance, reaching up to 5.6 mAh or 12.6F per individual ZHSC, equivalent to 12.5Fcm–3 by volume. This performance not only outperforms commercial coin-cell supercapacitors but also aligns closely with the performance metrics of certain commercial coin-cell aqueous batteries. This approach provides a viable solution for augmenting the volumetric specific capacity of carbon electrodes in ZHSCs.

Cu@MOF based composite materials: High performance anode electrodes for lithium-ion and sodium-ion batteries

In order to satisfy the increasing demand for energy, it is essential to improve the efficiency of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) batteries. Metal selenides (MSes) have a high theoretical specific capacity, can be designed in a variety of ways, conduct electricity well, can change morphology easily, and have a multi-electron reaction mechanism. These characteristics make them very competitive as anode materials for LIBs and SIBs. Herein, we synthesise Cu@MOF and Cu@NH2-MOF as the precursor to prepare Cu1.95Se embedded into porous carbon matrix (Cu1.95Se@PC) and porous-N-doped carbon matrix (Cu1.95Se@NPC) via pyrolysis process of Cu@MOF and Cu@NH2-MOF, respectively. Cu1.95Se@PC and Cu1.95Se@NPC electrodes for half-cell LIBs and SIBs exhibit a high reversible capacity of 313.1, 480.9 (for LIBs), 216.3 and 303.8 (for SIBs) mAhg−1after 1000 cycles at 2 A g−1, respectively. We assess the electrochemical performance of the Cu1.95Se@PC and Cu1.95Se@NPC anodes by integrating them with commercially available LiFePO4 (LFP) into full-cell LIBs. The LFP//Cu1.95Se@PC and LFP//Cu1.95Se@NPC full-cells have discharge capacities of approximately 330 and 293 mAh g−1 at 0.3 A g−1 at the initial cycle. In order to explore the sodium storage mechanism of the Cu1.95Se composites, we conducted an in situ XRD test during the first charge/discharge cycle, considering their favourable cycling and rate performance. Our work provides a promising anode electrode material for both half-cell LIBs and SIBs with high volume utilization and superior electrochemical performances.

Promotion effect of nitrogen doping on the low-temperature NH3-SCR of NO over activated carbon: Characterization and mechanism analysis

Heteroatom nitrogen doping in carbon catalysts is recognized an effective strategy for tailoring the properties of carbon catalysts for various flue gas de-NOx applications. However, accurately discerning the active structures after nitrogen doping and elucidating the promotion effect on low-temperature selective catalytic reduction activity remains a formidable challenge under different nitrogen doping preparation conditions. In this study, a series of nitrogen-doped activated carbon catalysts was synthesized through the L16(45) orthogonal array design method, and the degree of influence of various preparation conditions on de-NOx catalytic activities was also assessed. The optimal preparation conditions determined by range analysis were employed to synthesize NOAC-17, achieving the NO conversion of 95% and N2 selectivity of 99% at 300 °C, respectively. Subsequently, various characterization results proved that nitrogen doping induced the formation of abundant basic groups. The imine, amide, amine, and N-6 groups altered the acid-base of the activated carbon surface and increased the adsorption of acidic NOx. The N-5 and N-Q groups enhanced electronic interaction in the carbon matrix and accelerated electron mobility in the catalytic reaction process. Moreover, the N-6 group played multiple roles beyond the aforementioned effect due to its special structure. It also enhanced the accumulation of oxygen vacancies, which were closely associated with further oxidation of adsorbed NO. The lone electron pair in the N-6 group within the activated carbon framework can alter the polarity of the catalyst, thereby exerting a positive influence on the adsorption and activation of NH3. The nitrogen-doped catalyst identified through range analysis of the orthogonal experiment primarily facilitated the NH3-SCR reaction via the E-R mechanism with supplementary contribution from L-H mechanism at low temperatures. The nitrogen doping conditions obtained for the activated carbon catalyst provide valuable insights for the strategic enhancement of its catalytic performance in low-temperature NH3-SCR reactions.

Multiscale numerical scheme on shear failure feature of 3DOWC/Cs bar incorporating microlevel uncertainties and coupled constitutive behavior

In contrast to prevalently utilized carbon fiber reinforced plastics (CFRP), the carbon fiber reinforced carbon matrix composites (C/Cs) frequently present significantly divergent mechanics features. The current investigation dedicates to a robust multiscale finite element strategy on shear failure characteristics of three-dimensional orthogonal woven C/Cs (3DOWC/Cs) bolt bar together with relevant experimental measurement for validation, while the off-axial orientation sensibility of structural load-bearing performance and damage mechanism are systematically evaluated. In view of the complicated internal fabric architecture, the predictions are received via hierarchical numerical simulation at micro-, meso-, as well as macroscales. The random distributions of voids and fibers are incorporated to precisely capture the material properties, meanwhile the constitutive laws which embed the combining of Hashin and Puck criterions judging for yarn initial damage, multilinear rule for carbon matrix, and trilinear cohesive zone model (CZM) for interface, are implemented to render the coupling impacts of material behaviors. Besides, the extracted global load-displacement curves and local progressive failure morphologies from macroscale simulation are separately compared with experimental acquisitions to verify the accuracy of proposed modelling and to expose the damage mechanism of specimens with various off-axis angles. The contribution of this research lies in accurate quantification for microlevel uncertainties via modified stochastic algorithms, and applicable constitutive frame severally matching each material component to portray the distinctive mechanical particularities of 3DOWC/Cs.i

Insights into novel phosphorus-doped biochar for tetracycline removal: non-radical oxidation and adsorption

Heteroatom doping has been widely recognized as an emerging and promising strategy for material enhancement and the degradation of organic pollutants. However, most heteroatom doping biochars are used to activate, for example, PMS to generate reactive oxygen species (ROS) to degrade organic pollutants instead of investigating their own ability to produce ROS. Herein, phosphorus-doping biochars (PBC) were synthesized at various temperatures for adsorption and degradation of tetracycline (TC). Compared to the pristine biochar (BC-800), PBC-800 exhibited significant enhancements in the specific surface areas (1307.30 m2·g-1), porosity (0.94 cm3·g-1) and higher removal efficiency (1.25 times higher than BC-800). The abundance of functional groups in the PBC-800 such as electron-rich ketone functional groups (C=O), phosphorus-oxygen moieties (P-O), and defective sites within the carbon matrix, have been identified to play crucial roles in TC degradation. The free radical quenching and analysis of electron paramagnetic resonance (EPR) indicated that the presence of persistent free radicals (PFRs) on PBC also influenced the TC removal, and the possible non-radical pathways were proposed. The density functional theory (DFT) calculations proved that PBC-800 exhibited the highest adsorption energy as well as the lowest energy gap between triplet O2 and 1O2, suggesting that the existence of P was conducive to the production of 1O2. This study laid the groundwork for the development of biochars and provided a novel insight into the design of green biomass for effective removal of antibiotics in the future.

A K2C2O4/nano-CaCO3 dual-templated method to prepare rich nitrogen-doped hierarchical porous carbon with excellent lithium storage performance

Three-dimensional interconnected porous carbon with diverse guest element doping is considered one of the most promising anode materials in lithium-ion batteries (LIBs) owing to their large lithium storage capacity and the acceleration effects on the electrochemical kinetics. However, the regulation of desirable pore structure and guest element amount and species for high energy density and stable cycling performance is still challenging. Herein, sucrose-based hierarchical N-doped porous carbon (SHC-750) is prepared via a facile one-step carbonization/activation process at 750 °C for 1 h. The K2C2O4 and nano-CaCO3 are employed as the dual activating-agent/template, and the urea is used as an N source. Benefiting from the hierarchical porous structure, abundant defects, and high amount of N/O-containing functional groups with a multi-chemical state, SHC-750 delivers an excellent reversible specific capacity (1051.2 mAh/g at 0.1 A/g and) and great cycling stability. Moreover, SHC-750 exhibits fast lithium ions diffusion kinetics, which is attributed to the special ordered and hierarchical pore structure. This work provides a new pathway for the preparation and application of 3D interconnected porous carbon materials in the field of electrodes.

Preparation of N, S co-doped carbon nanotubes composites by coal pyrolysis for the CO2 capture

In this paper, nitrogen and sulfur co-doped carbon nanotubes composites were prepared by coal pyrolysis with the aim of applying them to carbon dioxide adsorption. Compared with previous carbon nanotubes modification methods, this study increased the specific surface area, microporosity and the number of adsorption sites of the materials through structural modification and surface modification, thus improving the adsorption capacity. Notably, secondary KOH activation modification was employed to increase the N and S elemental content in the adsorbent. Without leading to the loss of specific surface area, the specific surface area after modification was increased by 29% to 1875 m2/g, and the N content in the adsorbent could be reasonably regulated. The IAST calculations revealed that the prepared adsorbent had a high selectivity for CO2/N2 in binary gas mixtures, which is of practical significance for the treatment of flue gas streams. In addition, the isocratic heat of adsorption of the adsorbent was calculated to be less than 40kJ/mol using the Clasius-Clapeyron equation, which indicates that the adsorbent is easy to desorb and can be used several times. After five consecutive CO2 adsorption experiments, the adsorbent retained 98.22% of its CO2 adsorption capacity. Overall, this study not only provides a new idea for the high value-added utilization of low-rank bituminous coal. It also provides an important reference for the large-scale doping of N and S elements in coal-based carbon materials, which has certain theoretical and applied values.

Cathodic catalyst from lemon peel-based hydrogel for application in a SCMFC

In this investigation, a hydrogel has been prepared with the filling of lemon peel powder (LP) at three different concentrations of 1, 1.5, and 2 g (CS-PF/LP1, CS-PF/LP1.5, and CS-PF/LP2), in a mixture of phenol formaldehyde resin and chitosan, and they are pyrolyzed at 700°C to get soluble metal and nitrogen-doped carbon as cathode catalysts for oxygen reduction reaction (ORR). Several analytical characterization results confirmed the presence of inherent metallic content (or soluble metal) in the LP power. Among the three, CS-PF/LP1 provides the maximum surface area of 259.38 m2g-1, which is confirmed by the BET analysis. Additionally, the highest conductivity and catalytic activity of CS-PF/LP1 are also confirmed by electrochemical analysis. Thus, CS-PF/LP1 was selected to be used in a single-chamber microbial fuel cell (SCMFC) as a cathode catalyst. A maximum power density of 170.67 mWm-2 is obtained for CS-PF/LP1 which is 5.70 times higher than the base catalyst (without LP). Therefore, the present work uses LP, a waste material to develop a porous carbon material that can be used as an efficient cathode catalyst using solely the soluble metals of LP, for ORR in SCMFC for efficient power generation.

Bamboo waste derived hard carbon as high performance anode for sodium-ion batteries

Biomass-derived hard carbon stands out as one of the most promising anode materials for advancing the commercial viability of sodium-ion batteries (SIBs). In this study, we harnessed a straightforward and eco-friendly two-step carbonization approach to fabricate high-performance hard carbon materials, ingeniously repurposing industrial bamboo waste. Concurrently, we delved into the impact of carbonization temperature on the microstructure and properties of the hard carbon derived from bamboo waste. The findings revealed that the as-prepared hard carbon at 1400 °C (HCB-1400) showcased the most desirable sodium-ion storage capabilities. The HCB-1400 material not only can deliver a substantial reversible capacity of 328.4 mAh g−1 at 30 mA g−1 in its maiden charge-discharge cycle but also display remarkable cycling stability. Moreover, the HCB-1400//Na3V2(PO4)3 full cell, when assembled, exhibited an impressive energy density of 249.25 Wh kg−1, with a capacity retention rate of 93 % after enduring 200 cycles at a current density of 1.0 C. This research underscores the potential of transforming biomass waste into high-performance hard carbon, heralding a sustainable path for SIB applications.

Prediction and Optimization Design of Porous Structure Properties of Biomass-Derived Biochar Using Machine Learning Methods

Biochar produced from biomass by pyrolysis and activation is a platform porous carbon material that has been widely used in many areas. The porosity properties of biochar such as specific surface area (SSA), total pore volume (Total_PV), micropore volume (Micro_PV), mesopore volume (Meso_PV), and average pore size (Average_PS) are essential to biochar applications. Although previous machine learning (ML) models can precisely predict SSA and Total_PV, these models are unable to comprehensively predict the other porosity characteristics. More importantly, activation, which is a critical process for preparing high-porosity biochar, was generally not considered in previous studies. Here, six single-target models were established first based on pyrolysis & activation conditions for the prediction of SSA, Total_PV, Micro_PV, Meso_PV, Average_PS, and yield, obtaining test R2 of 0.89, 0.86, 0.88, 0.89, 0.76 and 0.91, respectively. Then, a multi-target model was established for simultaneous prediction with an average test R2 of 0.87. ML model interpretation indicated agent type and ratio were crucial to porosity properties. Finally, activation and direct pyrolysis biochar production optimum schemes were derived from ML model for a high porosity. Favorable experimental verification results were obtained with validation R2 of 0.98, indicating the great potential of using ML for biochar engineering.

Porous and high specific surface area carbon material derived from ginkgo leaves for high-performance symmetric supercapacitors

Porous and high specific surface area carbon material derived from ginkgo leaves for high-performance symmetric supercapacitors

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.

Trimetallic FeNiCu Atomic Clusters Supported on Carbon Matrix: Highly Active Catalysts for C3H6–SCR of NO

Trimetallic FeNiCu Atomic Clusters Supported on Carbon Matrix: Highly Active Catalysts for C₃H₆–SCR of NO

The effect of humidity on the enhanced CO2 adsorption of amine-functionalized microporous activated carbon.

Cost-effective and environmentally friendly sorbents were created for capturing CO2 by incorporating monoethanolamine (MEA) and tetraethylenepentamine (TEPA) onto a microporous activated carbon (AC) material. The application of a KOH reagent enhanced the surface area and pore volume of the carbon material. The BET, SEM, EDX, and FTIR techniques were employed to analyze the structural and surface properties of the developed samples. Raw AC possessed the highest surface area and largest micropore volume equal to 786 m2/g and 0.33 cm3/g, respectively. The amine impregnation increased the nitrogen content of the carbon material, but it also significantly reduced the BET surface area and total pore volume, which are primarily responsible for physically adsorbing CO2 towards ACs. The CO2 adsorption performance of the raw and impregnated ACs was experimentally evaluated using thermogravimetric analysis (TGA) at different adsorption temperatures (25 and 50 °C) and CO2 concentrations (10 and 90 vol.%). The findings demonstrated that the raw AC exhibited the highest capacity for CO2 adsorption. Specifically, at a temperature of 25 °C and pressure of 1 bar (10 vol.% CO2, N2 balance), the raw AC achieved an uptake of 1.2 mmol/g, which was 60.3% and 79.3% higher compared to the CO2 uptake of MEA-AC (0.5 mmol/g) and TEPA-AC (0.3 mmol/g), respectively. It is surprising that the combined uptake of CO2 + H2O increased by 12.5 and 23.4 wt.% (equivalent to 7 and 13 mmol/g) for MEA-AC and TEPA-AC, respectively, when humid flue gas was taken into account under the conditions of 50 °C, with 10 vol.% CO2, 4 vol.% H2O, and N2 balance. These results indicate that the presence of H2O facilitates the chemisorption of CO2 by the novel and highly promising carbon-based sorbent prepared in this study, leading to an increased capacity for adsorbing CO2 under water vapor containing flue gases.