High Degree Of Graphitization Research Articles

Hierarchical porous graphene nanosheets derived from moso bamboo with superior supercapacitor performance

Moso bamboo is regarded as a kind of biomass resource with abundant reserves in nature, and how to achieve its high-value utilization is one of the important research topics widely concerned by the academic community. In this work, hierarchical porous graphene nanosheets with wrinkled structures derived from the natural moso bamboo is obtained via a compact two-step processing method including pyrolysis and chemical activation. The as-prepared ABC-950 possess a large specific surface area of 1758 m2 g−1, pore volume of 1.55 cm3 g−1, mesopores ratio of 75.5 % and high graphitization degree with ID/IG as low as 0.43. With these merits, as the electrode material for supercapacitor, the ABC-950 exhibits a high specific capacitance of 459.4 F g−1 at 1 A g−1 and an excellent rate performance of 82.3 % in 6 M KOH electrolyte. Moreover, the ABC-950 based symmetric supercapacitor shows superior specific capacitance of 112.3 F g−1 at 0.5 A g−1 and an attractive energy density of 15.6 Wh·kg−1 at 250 W kg−1. Moreover, outstanding capacitance retention of about 102.1 % even after 30,000 charge-discharge cycles at a large current density of 10 A g−1. Our work offers a promising method to easily transform moso bamboo into porous graphene nanosheets for the electric energy storage.

Cobalt-catalyzed soft-hard carbon composite anodes for enhanced sodium-ion storage

Hard carbon is expected to be a high-capacity anode material for sodium-ion batteries (SIBs). However, its Na+ storage performance, especially the low discharge capacity, remains a great challenge. Herein, the soft-hard carbon composite anodes with high degree of graphitization were synthesized via low-temperature pyrolysis (at only 900 °C) of Cobalt-catalyzed perylene tetracarboxylic dianhydride (PTCDA-Co) and cotton, with subsequent removal of cobalt. The composite resulting from a 2:3 mass ratio of soft to hard carbon exhibits a good discharge capacity of 355.81 mAh g−1 at a current density of 50 mA g−1 and an enhanced initial Coulombic efficiency (ICE) of 81.41%. The enhanced electrochemical storage performance of cotton is attributed to the introduction of PTCDA-Co, which creates low-defect graphitic layer, hierarchical porous channels, and carbon shielding coating on hard carbon.

Enhancing the supercapacitive performance of a carbon-based electrode through a balanced strategy for porous structure, graphitization degree and N,B co-doping

Regarding carbon-based electrodes, simultaneously establishing a well-defined meso-porous architecture, introducing abundant hetero-atoms and improving the graphitization degree can effectively enhance their capacitive performance. However, it remains a significant challenge to achieve a good balance between defects and graphitization degree. In this study, the porous structure and composition of carbon materials are co-optimised through a ‘dual-function’ strategy. Briefly, K3Fe(C2O4)3 and H3BO3 were hybridised with a gelatin aqueous solution to form a homogeneous composite hydrogel, followed by lyophilisation and carbonisation. Owing to the dual functionality of raw materials, the graphitization, activation and hetero-atom doping processes can occur simultaneously during a one-step high-temperature treatment. The resultant carbon material exhibits a high graphitization degree (ID/IG = 0.9 ± 0.1), high hetero-atom content (N: 9.0 ± 0.3 at.%, B: 6.9 ± 0.5 at.%) and a large specific area (1754 ± 58 m2/g). The as-prepared electrode demonstrates a superior capacitance of 383 ± 1F g−1 at 1 A/g. Interestingly, the cyclic voltammetry (CV) curves exhibit a distinctive pair of broad redox peaks, which is uncommon in KOH electrolyte. Experiment data and density functional theory (DFT) simulation verify that N-5, B co-doping enhances the activity of the faradic reaction of carbon electrodes in KOH electrolyte. Furthermore, the fabricated Zn-ion hybrid supercapacitor (ZHSC) based on this carbon electrode delivers a high-energy density of 140.7 W h kg−1 at a power density of 840 W kg−1.

Catalytic Decomposition of CH4 to Hydrogen and Carbon Nanotubes Using the Pt(1)-Fe(30)/MCM-41 Catalyst

The catalytic decomposition of CH4 to H2 and carbon nanotubes (CNTs) was investigated regarding Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 using a fixed-bed flow reactor under an atmosphere. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), and Raman spectroscopy were used to characterize the behavior of Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41. The hydrogen yield of Pt(1)-Fe(30)/MCM-41 was 3.2 times higher than that of Fe(30)/MCM-41. When 1 wt% of Pt was added to Fe(30)/MCM-41(Mobil Composition of Matter No. 41), the atomic percentage of Fe2p increased from 13.39% to 16.14% and the core Fe2p1/2 electron levels of Fe0 and Fe2+ chemically shifted to lower energies (0.2 eV and 0.1 eV, respectively) than those of Fe(30)/MCM-41. The Fe, Pt, Si, and O nanoparticles were uniformly distributed on the catalyst surface, and the average iron particle sizes of the Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 were about 33.4 nm and 58.5 nm, respectively. This is attributed to the uniform distribution of the nano-sized iron particles on the MCM-41 surface, which was due to the suitable metal-carrier interaction (SMCI) between Fe, Pt, and MCM-41 and the high reduction degree of Fe due to the spillover effect of H2 from Pt to Fe. Pt(1)-Fe(30)/MCM-41 produced multiwalled CNTs and bamboo-shaped CNTs with high crystallinity and graphitization degree using the tip-growth mechanism, with an ID/IG ratio of 0.93 and a C(101)/C(002) ratio of 0.64.

MnFe@N-CNTs Based Lactate Biomicrochips for Nonintrusive and Onsite Periodontitis Diagnosis.

In clinical settings, saliva has been established as a straightforward, noninvasive medium for diagnosing periodontitis. However, the precise diagnosis is often hampered by the absence of a specialized analyzer capable of detecting low concentrations of biomarkers typically found in saliva. In this study, we present a noninvasive, on-site screen-printed biomicrochip specifically engineered for the precise and sensitive quantification of lactate concentrations in saliva, a critical biomarker in the diagnosis of periodontitis. The microchip is constructed using a nanostructured ink formulation that includes MnFe@N-doped carbon nanotubes (MnFe@N-CNTs). These MnFe@N-CNTs exhibit a high degree of graphitization and low electrical resistance, significantly augmenting the electrocatalytic efficiency of the enzymatic reaction of lactate. This results in doubled sensitivity and a detection limit that surpasses those of the current advanced salivary assay methods. Remarkably, within just 30 s, the biomicrochip can quantitatively and precisely measure lactate concentrations in the saliva of 10 patients, which provides valuable insights into the severity of their periodontitis. This biosensor holds excellent potential for large-scale production and could broaden the scope of biomarker recognition, paving the way for the analysis of a wider range of oral diseases.

Sustainable mechanochemical synthesis of catalytically graphitized mesoporous carbons

So far it is difficult to achieve both a high graphitization degree and uniform mesopores in carbons, especially via a sustainable synthesis approach. This work shows that mesoporous graphitized carbons predominantly composed of amorphous and/or partially graphitic carbon nanotubes can be obtained by a simple mechanochemical synthesis using tannins as carbon precursors, iron salt as a graphitization catalyst and block copolymer as a soft template. The one-pot synthesis relied on the fast ball milling of a Pluronic-type template, tannins, and iron salt, followed by the direct thermal treatment at a certain temperature (e.g., 750 °C) leading to mesoporous carbons with a high degree of graphitization (up to 75%), high specific surface areas up to 360 m2/g, and large mesopore volumes up to 0.40 cm3/g. Moreover, the procedure can be extended for the synthesis of highly porous activated carbons with uniform mesoporosity by adding potassium oxalate to the milling system. The procedure afforded activated mesoporous carbons with substantially uniform mesopores of about 7.7 nm, a high specific surface area of 1100 m2/g, a large pore volume of 0.84 cm3/g, and enhanced CO2 adsorption capacity up to 4.0 mmol/g at ambient conditions. This synthetic approach offers advantages in terms of scalability, simplicity, and reduced environmental impact in comparison to traditional synthesis methods.

The total use of rice husk to create highly porous silicon and sulfur-doped activated carbon for the fabrication of high-performance silicon-anode lithium-ion capacitors

The promising advantages between the high energy density of lithium-ion batteries and the high power density of supercapacitors are hybridized to construct lithium-ion capacitors (LICs). The high capacity of anode materials is challenging for high-performance LICs. Simultaneously, the quest for sustainable and environmentally friendly energy storage materials has attracted attention. In this work, rice husk was treated with alkaline to separate silica and biochar, followed by magnesiothermic reduction and thermal activation to produce porous silicon (PSi) and sulfur-doped activated carbon (SAC), respectively. The PSi had high porosity for accommodating volumetric expansion during cycling, resulting in outstanding rate capability and cycling stability, whereas the SAC had a high surface area with micro- and mesopores (2511 m2 g−1), a high degree of graphitization, and excellent electrochemical performance. For the fabrication of half-cell lithium-ion batteries, PSi gave a specific capacity of 1005.3 mAh g−1 between 0.01 and 2 V, while SAC provided a specific capacity of 108 mAh g−1 (2.0–4.5 V), and showed a better electrochemical stability than the both commercial silicon and activated carbon. When a full-cell LIC was fabricated, the optimized P-Si//SAC LIC had a high energy density of 107 Wh kg−1 at a power density of 163 W kg−1 and a capacitance retention of 81.3 and 61.8% between a potential range of 2.0–4.5 V after 1000 and 3000 charge-discharge cycles, respectively. This study not only turned agricultural waste into valuable, high-performance LICs but also made significant progress toward the creation of environmentally responsible, long-lasting, and sustainable energy storage systems.

Novel cow dung-doped sludge biochar as an efficient ozone catalyst: Synergy between graphitic structure and defects induces free radical pathways

A composite material, cow dung-doped sludge biochar (Zn@SBC-CD), was synthesized by one-step pyrolysis using ZnCl2 as an activating agent and applied to a catalytic ozonation process (COP) for methylene blue (MB) removal. SEM, XRD, FTIR, XPS and BET analyses were performed to characterize the biochar (BC) catalysts. Zn@SBC-CD had high graphitization degree, abundant active sites and uniform distribution of Zn on its surface. Complete removal of MB was achieved within 10 min, with a removal rate much higher than that of ozone alone (32.4%), implying the excellent ozone activation performance of Zn@SBC-CD. The influence of experimental parameters on MB removal efficiency was examined. Under the optimum conditions in terms of ozone dose 0.04 mg/mL, catalyst dose 400 mg/L and pH 6.0, COD was completely removed after 20 min. Electron paramagnetic resonance (EPR) analysis revealed radical and non-radical pathways were involved in MB degradation. The Zn@SBC-CD/O3 system generated superoxide anion radicals (•O2−), which were the main active species for MB removal, through adsorption, transformation, and transfer, Furthermore, Zn@SBC-CD exhibited good reusability and stability in cycling experiments. This study provides a novel approach for the utilization of cow dung and sludge in synthesis of functional biocatalysts and application in organic wastewater treatment.

Simple modification of phenylphosphonic acid to construct polyester-cotton fabrics with high flame retardancy

Polyester-cotton fabrics (PTCO) have excellent properties and are ubiquitous in daily life, but their serious flammability brings great safety hazards to people's lives. This study used phenylphosphonic acid (PPOA) and urea as raw materials to prepare a flame retardant named POU. PTCO/POU was prepared by the pad-dry-cure technique, and the performance was compared with that of PTCO/PPOA, revealing many interesting phenomena. Based on the gas phase and condensed phase flame-retardant mechanism brought by P/N synergy, PTCO/POU had better flame retardancy than PTCO/PPOA did. The damaged length was 6.7 cm, and the limiting oxygen index (LOI) value was 30.1%. The char residues after burning were complete and denser with a higher degree of graphitization. Thermogravimetric analysis showed that POU can significantly reduce the Rmax of PTCO, and improve its thermal stability in high temperature zones. The CCT results showed that PTCO/POU had the longest time to ignition and the smallest fire growth index, which was of great significance for reducing fire risk. The TG-FTIR results showed that the volatile products of PTCO/POU were greatly reduced, and during the burning process, NH3 was produced to dilute the concentration of combustible gases. In addition, PTCO/POU also had better whiteness performance than PTCO/PPOA did. This work greatly improved the flame retardancy of PTCO in a simple way and expanded its application prospects.

Porous and graphitic carbon nanosheets with controllable structure for zinc-ion hybrid capacitor

The imbalances of storage capacity and reaction kinetics between carbonaceous cathodes and zinc (Zn) anodes restrict the widespread application of Zn-ion hybrid capacitor (ZIHC). Structure optimization is a promising strategy for carbon materials to achieve sufficient Zn2+ storage sites and satisfied ion–electron kinetics. Herein, porous graphitic carbon nanosheets (PGCN) were simply synthesized using a K3[Fe(C2O4)3]- and urea-assisted foaming strategy with polyvinylpyrrolidone as carbon precursor, followed by activation and graphitization. Sufficient pores with well-matched pore sizes (0.80–1.94 nm) distributed across the carbon nanosheets can effectively shorten mass-transfer distance, promoting accessibility to active sites. A partially graphitic carbon structure with high graphitization degree can accelerate electron transfer. Furthermore, high nitrogen doping (7.2 at.%) provides additional Zn2+ storage sites to increase storage capacity. Consequently, a PGCN-based ZIHC has an exceptional specific capacity of 181 mAh g−1 at 0.5 A g−1, superb energy density of 145 Wh kg−1, and excellent cycling ability without capacity decay over 10,000 cycles. In addition, the flexible solid-state device assembled with PGCN exhibits excellent electrochemical performances even when bent at various angles. This study proposes a straightforward and economical strategy to construct porous graphitic carbon nanosheets with enhanced storage capacity and fast reaction kinetics for the high performance of ZIHC.

The Microstructure and Thermal Conductive Behavior of Three-Dimensional Carbon/Carbon Composites with Ultrahigh Thermal Conductivity.

Carbon-based composite materials, denoted as C/C composites and possessing high thermal conductivity, were synthesized utilizing a three-dimensional (3D) preform methodology. This involved the orthogonal weaving of mesophase pitch-based fibers in an X (Y) direction derived from low-temperature carbonization, and commercial PAN-based carbon fibers in a Z direction. The 3D preforms were saturated with mesophase pitch in their raw state through a hot-pressing process, which was executed under relatively low pressure at a predetermined temperature. Further densification was achieved by successive stages of mesophase pitch impregnation (MPI), followed by impregnation with coal pitch under high pressure (IPI). The microstructure and thermal conductivity of the C/C composites were systematically examined using a suite of analytical techniques, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and PLM, amongst others. The findings suggest that the volumetric fraction of fibers and the directional alignment of the mesophase pitch molecules can be enhanced via hot pressing. The high graphitization degree of the mesophase pitch matrix results in an increased microcrystalline size and thus improved thermal conductivity of the C/C composite. Conversely, the orientation of the medium-temperature coal pitch matrix is relatively low, which compensates for the structural inadequacies of the composite material, albeit contributing minimally to the thermal conductivity of the resultant C/C composites. Following several stages of impregnation with mesophase pitch and subsequent impregnation with medium-temperature coal pitch, the 3D C/C composites yielded a density of 1.83 and 2.02 g/cm3. The thermal conductivity in the X (Y) direction was found to be 358 and 400 W/(m·K), respectively.

Atomically dispersed Fe-N-C catalyst with densely exposed Fe-N4 active sites for enhanced oxygen reduction reaction

Atomically dispersed Fe-N-C catalysts are a promising alternative to platinum group metal (PGM) catalysts for oxygen reduction reaction (ORR). However, attaining efficient ORR activity and superior stability in Fe-N-C catalysts is still crucial yet challenging. Herein, we report a rational SiO2-mediated two-step pyrolysis strategy for stabilizing densely exposed Fe-N4 active sites on hierarchically porous carbon (HP-Fe-N-C/2). Benefiting from the high density of accessible Fe-N4 sites and the high graphitization degree of carbon support, the obtained HP-Fe-N-C/2 catalyst demonstrates outstanding activity and stability for ORR in both alkaline and acidic media. When used as the cathode catalyst, the assembled Zn-air battery shows a high peak power density of 217 mW cm−2 and ultra-long cycling stability for 1342 h without noticeable degradation. As a PGM-free cathode in proton exchange membrane fuel cells, it delivers a maximum output power density of 0.66 W cm−2.

Adsorptivity and mechanism investigation for auramine on sugarcane leaf-based activated carbon prepared with Ni(NO3)2/NH4H2PO4 as an activator

Water pollution causes serious harm to aquatic plants and human health, which is an urgent problem in the world. In this paper, sugarcane leaf-based activated carbon (PSLAC and NiPSLAC) was prepared with sugarcane leaves as raw material and NH4H2PO4 and Ni(NO3)2/NH4H2PO4 as activators, respectively, which was applied to the adsorption of auramine in dyeing wastewater. At the same time, the water consumption of the sample preparation process was studied. X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TG-DTG), fourier transform infrared spectrometer (FTIR), and Brunauer-Emmett-Teller (BET) were used to investigate the physicochemical properties of the samples. The water consumption of the NiPSLAC sample during the preparation process was 213.15 mL/g, which was 4.93%, 91.05%, 89.09%, 85.58%, and 54.18% of the NH4H2PO4, NaOH, KOH, K2CO3, and H3PO4 activated samples, respectively. The specific surface area and pore volume of the NiPSLAC sample were 1386.20 m2/g and 1.53 cm3/g, which were 410.57 m2/g and 0.46 cm3/g higher than the PSLAC sample, respectively. Compared with the PSLAC sample, the NiPSLAC sample had a higher graphitization degree and richer surface functional groups. Therefore, the NiPSLAC sample showed a higher adsorption capacity for auramine, reaching 164 mg/g, which was 1.12 times that of PSLAC, and the pseudo-second-order kinetic model and the Langmuir isotherm model could describe the adsorption process. This study provides a novel and advanced idea for developing a high-quality adsorbent for the removal of dyeing wastewater.

Synthesis and functionalization of carbon nanostructures in a single‐step CVD process through the implementation of a recycled precursor

AbstractBackgroundRecycled materials are a major research topics of the new era to relieve pressure on raw material extraction from our planet and reduce its pollution levels. This has helped us to reinvent our relationship with nature, and to commit ourselves to a sustainable economic and social reconstruction. An excellent option to add value to waste while protecting the environment is the synthesis of carbon nanostructures (CNSs) using a recycled material as a precursor. In this research, the synthesis and functionalization of CNSss in a single‐step chemical vapour deposition (CVD) process was carried out using a recycled precursor. The methanol fraction is waste from the distillation process in the production of alcoholic beverages. The synthesis temperatures were 750, 800 and 850 °C.ResultsAs a result, carbon nanotubes, carbon nanoribbons and carbon nanobeads with diameters <100 nm and widths <500 nm were obtained. The crystal size of CNSs decreased with increasing synthesis temperature, from 20 to 12 nm. RAMAN spectra revealed the high degree of graphitization and the presence of different types of nanostructures. Carbonyl (CO) and hydroxide (‐OH) stretching of the carboxylic acid were present in all samples.ConclusionThe results obtained shown that the CNSs synthetized are functionalized in a single‐step CVD process using the methanolic fraction as a precursor. © 2024 Society of Chemical Industry (SCI).

Corrosion Dynamics of Carbon-Supported Platinum Electrocatalysts with Metal-Carbon Interactions Revealed by In Situ Liquid Transmission Electron Microscopy.

Carbon support is essential for electrocatalysis, but limitations remain, as carbon corrosion can lead to electrocatalyst degradation and affect the long-term durability of electrocatalysts. Here, we studied the corrosion dynamics of carbon nanotubes (CNTs) and Vulcan carbon (VC) together with platinum (Pt) nanoparticles in real time by liquid cell (LC) transmission electron microscopy (TEM). The results showed that CNTs with a high degree of graphitization exhibited higher corrosion resistance compared to VC. Furthermore, we observed that the main degradation path of Pt nanoparticles in Pt/CNTs was ripening, while in Pt/VC, it was aggregation and coalescence, which was dominated by the interactions between Pt nanoparticles and different hybridization of carbon supports. Finally, we performed an ex situ CV stability test to confirm the conclusions obtained from in situ experiments. This work provides deep insights into the corrosion mechanism of carbon-supported electrocatalysts to optimize the design of electrocatalysts with a higher durability.

Mass synthesis of Pt/C catalysts with high Pt loading for low-overpotential hydrogen evolution

We present a facile and scalable method to synthesize Pt/C catalysts with high Pt loading (10–30 wt.%) using sodium polyacrylate resin (PAANa) as a multifunctional agent. PAANa can absorb H2PtCl6 solution and form a gel, which can be converted into Pt/C catalysts by pyrolysis. PAANa acts as a water absorber, a Pt stabilizer, and a carbon precursor. The optimized catalyst, pyrolyzed at 800 °C with a 20 wt.% Pt loading, demonstrates Pt nanoparticles measuring 3.5 nm in size. It exhibits excellent stability and achieves a low overpotential of 43 mV at a current density of 10 mA cm−2 for the hydrogen evolution in alkaline media. The enhanced catalytic activity is due to the combined influence of the nanoscale Pt particles, the higher degree of graphitization, and the porous carbon substrate with a large surface area. We also demonstrate the scalability of the method by producing 100 g of the catalyst in the laboratory.

Structural and compositional analysis of MOF-derived carbon nanomaterials for the oxygen reduction reaction.

The development of low-cost and efficient cathode catalysts is crucial for the advancement of fuel cells, as the oxygen reduction reaction (ORR) on the cathode is constrained by expensive commercial Pt/C catalysts and a significant energy barrier. Metal-organic frameworks (MOFs) are considered excellent precursors for synthesizing carbon nanomaterials due to their simple synthesis, rich structure and composition. MOF-derived carbon nanomaterials (MDCNM) inherit the morphology of their precursors at low dimensional scales, providing abundant edge defects, larger specific surface area, and excellent electron transport paths. Furthermore, the rich composition of MOFs enables the carbon nanomaterials derived from them to exhibit various physicochemical properties, including stronger electron gaining ability, oxygen affinity, and a higher degree of graphitization, resulting in excellent ORR activity. However, a more detailed analysis is necessary to understand the advantages and mechanisms of MDCNM in the field of the ORR. This review classifies and summarizes the structure and different chemical compositions of MDCNM in low dimensions, and provides an in-depth analysis of the reasons for their improved ORR activity. Additionally, the recent practical applications of MDCNM as cathode material in fuel cells are introduced and analyzed in detail, with a focus on the enhanced electrochemical performance.

Altering Coconut Shell Biomass to High-Ordered Graphitic Carbon with Nickel Catalyzation

Graphite is a carbon-based material potentially utilized in numerous applications, such as electrodes for supercapacitors, lithium-ion batteries, and absorbers for water treatment. Biomass graphite is a beneficial candidate for low-cost yet valuable graphite. In this work, coconut shells, the abundant materials with high carbon contents, were successfully transformed into valuable coconut shell graphite (CSG) using metal catalytic graphitization with nickel as a catalyst at low-temperature conditions of ~1200 °C. Nickel concentration varied between 2 mmol, 3 mmol, and 5 mmol per gram of carbon. The samples were further examined using X-ray diffraction (XRD), Raman Spectroscopy, and Transmission Electron Microscope (TEM). The high graphitization degree of ~ 72 % was confirmed by X-ray diffraction analysis. That was further supported by the high-ordered stacking carbon layer that appeared in HR-TEM images. Meanwhile, Raman spectroscopy confirms that nickel impregnation diminished the structural defect of samples and increased the sp2-carbon bond indicated by its rise of IG/ID. The IG/ID values of CGS and CGS-Ni5mmol are 0.86 and 0.92, respectively.

Porous carbon materials augmented with heteroatoms derived from hyperbranched biobased benzoxazine resins for enhanced CO2 adsorption and exceptional supercapacitor performance

Porous carbon materials doped with heteroatoms are an excellent alternative for applications in CO2 adsorption and supercapacitors. Herein, we present a new approach to obtain heteroatoms (N, O, and S) doped porous carbon materials using bio-based hyperbranched benzoxazine (RES-HP-BZ) as a precursor. Two types of porous carbon materials, poly(RES-HP-BZ)-700 and poly(RES-HP-BZ)-800, were synthesized through a simple calcination method by carbonization and KOH activation of benzoxazine at temperatures of 700 °C and 800 °C, respectively. The chemical structure, texture properties, and surface chemistry characteristics were validated through FTIR, NMR, SEM, XRD, and XPS, respectively. The resulting poly(RES-HP-BZ)-800 exhibited micro and meso porous characteristics with a high SBET of 841 m2 g−1, pore size of 1.14 nm, and pore volume of 0.70 cm3 g−1. The poly(RES-HP-BZ)-800 also showed a high graphitization degree and electrochemically energetic N-6, N-5, N-Q, O-2, and O-3 heteroatoms, which led to a high capacitance of 523 F g−1 (at 0.5 A g−1) as well as CO2 capture of 4.63 mmol g−1 at 298 K. These newly developed bio-based porous carbons derived from hyperbranched bio-benzoxazine with excellent electrochemical performance make them a promising candidate for eco-friendly supercapacitors.

Catalytic co-pyrolysis of waste tea residue and waste plastics to carbon nanomaterials: Catalyst support, reaction temperature and product application

The search for cost-effective, high-performance catalysts is crucial in catalytic co-pyrolysis. Different Fe-Mo@X catalysts (X = Al2O3, MgO) and reaction temperatures (600 ℃, 700 ℃, 800 ℃, 900 ℃) were tested to optimize hydrogen production and carbon quality while also exploring CNTs degradation performance. The results indicate that both catalyst type and operating parameters are highly dependent on the growth of carbon nanotubes and hydrogen. The FeMo@Al2O3 catalyst exhibits superior catalytic activity attributed to its more abundant mesoporous structure and higher specific surface area. Specifically, FeMo@Al2O3 achieved the highest yield of carbon nanotubes (84.42%) at 700 ℃, and attained the maximum hydrogen yield (49.57%) at 900 ℃. However, the CNTs synthesized from FeMo@MgO exhibited fewer defects, higher graphitization degree and purity (Raman and TPO). CNTs/MgO significantly enhanced the degradation efficiency of Clothianidin by virtue of their superior electron transport properties and chemical bonding between MgO and CNTs.