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Graphite is considered to be the most auspicious anode candidate for potassium ion batteries. However, the inferior rate performances and cycling stability restrict its practical applications. Few studies have investigated the modulating the graphitization degree of graphitic materials. Herein, a nitrogen‐doped carbon‐coated carbon fiber composite with tunable graphitization (CNF@NC) through etching growth, in‐situ oxidative polymerization, and subsequent carbonization process is reported. The prepared CNF@NC with abundant electrochemical active sites and a rapid K+/electron transfer pathway, can effectively shorten the K+ transfer distance and promote the rapid insertion/removal of K+. Amorphous domains and short‐range curved graphite layers can provide ample mitigation spaces for K+ storage, alleviating the volume expansion of the highly graphitized CNF during repeated K+ insertion/de‐intercalation. As expected, the CNF@NC‐5 electrode presents a high initial coulombic efficiency (ICE) of 69.3%, an unprecedented reversible volumetric capacity of 510.2 mA h cm−3 at 0.1 A g−1 after 100 cycles with the mass‐capacity of 294.9 mA h g−1. The K+ storage mechanism and reaction kinetic analysis are studied by combining in‐situ analysis and first‐principles calculation. It manifests that the K+ storage mechanism in CNF@NC‐5 is an adsorption‐insertion‐insertion mechanism (i.e., the "1+2" model). The solid electrolyte interphase (SEI) film forming is also detected. [ABSTRACT FROM AUTHOR]

Spatially dual-confined Ni-dope CoS 2 @NC@C microrods (Ni-CoS 2 @NC@C) are developed via structural design, heteroatom doping and carbon confinement to boost sodium storage performance of the material. [Display omitted] Currently, conversion-type transition metal sulfides have been extensively favored as the anodes for sodium-ion batteries due to their excellent redox reversibility and high theoretical capacity; however, they generally suffer from large volume expansion and structural instability during repeatedly Na+ de/intercalation. Herein, spatially dual-confined Ni-doped CoS 2 @NC@C microrods (Ni-CoS 2 @NC@C) are developed via structural design, heteroatom doping and carbon confinement to boost sodium storage performance of the material. The morphology of one-dimensional-structured microrods effectively enlarges the electrode/electrolyte contact area, while the confinement of dual - carbon layers greatly alleviates the volume change-induced stress, pulverization, agglomeration of the material during charging and discharging. Moreover, the introduction of Ni improves the electrical conductivity of the material by modulating the electronic structure and enlarges the interlayer distance to accelerate Na+ diffusion. Accordingly, the as-prepared Ni-CoS 2 @NC@C exhibits superb electrochemical properties, delivering the satisfactory cycling performance of 526.6 mA h g−1 after 250 cycles at 1 A g−1, excellent rate performance of 410.9 mA h g−1 at 5 A g−1 and superior long cycling life of 502.5 mA h g−1 after 1,500 cycles at 5 A g−1. This study provides an innovative idea to improve sodium storage performance of conversion-type transition metal sulfides through the comprehensive strategy of structural design, heteroatom doping and carbon confinement. [ABSTRACT FROM AUTHOR]

While nano-crystalline diamond (NCD) is a promising engineering composite material for its unique mechanical properties, achieving the ultrahigh surface quality of NCD-based components through conventional grinding and polishing is challenging due to its exceptional hardness and brittleness. In the present work, we experimentally investigate the nanosecond laser ablation-induced graphitization characteristics of NCD, which provides a critical pretreatment method of NCD for realizing its superlative surface finish. Specifically, systematic experimental investigations of the nanosecond pulsed laser ablation of NCD are carried out, in which the characteristics of graphitization are qualitatively characterized by the Raman spectroscopy detection of the ablated area of the microhole and microgroove. Subsequently, the influence of laser processing parameters on the degree and morphological characteristics of graphitization is evaluated based on experimental data and related interpretation, from which optimized parameters for maximizing the graphitization of NCD are then identified. The findings reported in the current work provide guidance for promoting the machinability of NCD via laser irradiation-induced surface modification. [ABSTRACT FROM AUTHOR]

SiMo ductile cast iron combines ease of part fabrication with good mechanical properties, including a usable plasticity range. Its poor corrosion resistance inherited from grey cast iron could be alleviated through alloying with Al or Cr additions capable of forming a dense oxide scale protecting the substrate. However, the presence of Al and Cr in cast iron tends to make the material brittle, and their optimum alloying additions need to be studied further. The present work was aimed at investigating the effect of crystallization rates on microstructure changes during directional crystallization of SiMo-type alloys with up to 3.5% Al and 2.4% Cr. The experiment was performed using the Bridgman–Stockbarger method. The tubular crucible was transferred from the hot section to cold section at rates ranging from 5 mm/h to 30 mm/h with a 4/5 crucible length and then quenched. The introduced Al promoted graphitization up to a point, wherein, at the highest applied addition, the graphite precipitation preceded crystallization of the rest of the melt. A rising level of Cr in these alloys from 1% to 2.4% resulted in the formation of low and high contents of pearlite, respectively. The higher crystallization rates proved effective in increasing the ferrite content at the expense of pearlite. In the investigated cast iron samples with smaller applied alloying additions, Widmanstätten ferrite or ausferrite, i.e., fine acircular phase, were often found. The switch from directional crystallization to quenching caused a transition from a liquid to solid state, which started with nucleation of islands of fine austenite dendrites with chunky graphite eutectic separating them. As these islands expanded, they pushed alloying additions to their sides, promoting carbide or pearlite formation in these places and forming a super-cell-like structure. The performed experiments helped gather information concerning the sensitivity of the microstructure of SiMo cast iron modified with Al and Cr to crystallization rates prevailing in heavy cast structures. [ABSTRACT FROM AUTHOR]

The coal indirect liquefied diesel soot (Coal‐to‐liquids diesel soot, CS) was collected by a self‐made soot trapper. CS was modified with cetyltrimethyl ammonium bromide (CTAB) and named as CS‐CTAB. The tribological properties of CS and CS‐CTAB in 10#white oil(10#WO) were tested on a WTM‐2E controlled atmosphere miniature friction and wear testing machine. The morphology, composition, and tribological mechanism of CS and modified CS‐CTAB were studied by using TEM, XPS, XRD, Raman, and other instruments. The results showed that CS modified by CTAB is wrapped and entangled in long chains. Their main structure components are all amorphous carbon with a small amount of graphite crystallites. The addition of CS‐CTAB (0.8 wt%) significantly reduces both AFC and wear rate, with reductions of 32.9% for AFC, and 65.6% for wear rate compared to no additive. The anti‐friction and anti‐wear effect of CS is greatly improved after being modified by CTAB. Mechanism analysis shows that CS as a lubricant additive, acts as a micro‐bearing in the friction process and falls off under the action of shear force to generate an independent graphite sheet, thus forming a graphite protective film on the surface of 304 stainless steel plate. However, CS has the defects of low graphitization degree, large particle size, and easy agglomeration. During friction, uneven adsorption of CS on the surface can worsen wear. However, CTAB modification can improve dispersion stability in 10#WO and effectively reduce wear on the friction surface. [ABSTRACT FROM AUTHOR]

Industrially prepared artificial graphite (AG) is attractive for potassium-ion batteries (PIBs), but its rate performance is poor and the production process is energy intensive, so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically important. Herein, a nanostructured graphite composed of multi-walled carbon nanotubes (MWCNTs) and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework (MOF) and carbon source. The high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency (ICE) exceed 80%, and the three-dimensional (3D) conductive network ensures a specific capacity of 234 mAh·g−1 after 1000 cycles at a high current density of 500 mA·g−1. In addition, the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction (XRD) and in situ Raman spectroscopy, and its practicality is also proved by the voltage of the full cells. This work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage. [ABSTRACT FROM AUTHOR]

Non-impregnated small-pore graphite (NSPG), which has a compact microstructure and is used in molten salt reactors (MSRs), was prepared by a novel process. The pore diameter of NSPG was reduced to ~800 nm. The irradiation evaluation of NSPG was carried out by 7 MeV Xe26+ ion irradiation. The microstructural changes of NSPG were investigated with IG-110 as a comparison. The graphitization degree of NSPG was higher than that of IG-110, though it was not subjected to an impregnation process. Under low-dose ion irradiation (<2.5 dpa), the microscopic morphology of the NSPG changes in a small magnitude, and the lamellar structure of graphite remains within the scale of more than a dozen nanometers, which exhibits a better resistance to irradiation. With the increase in irradiation dose, the accumulation of defects leads the graphite toward amorphization, which shows consistency with IG-110. This study provides an efficient and low-cost method for the preparation of graphite for MSR, and investigates the damage behavior of graphite, which is of great significance in accumulating data for the development of MSR nuclear graphite and the optimal design of graphite materials. [ABSTRACT FROM AUTHOR]

The automatic graphitization system (AGE3) by IonPlus is very popular among radiocarbon dating laboratories. Usually, solid samples are burnt in an elemental analyzer (EA), and the gaseous CO2 is transferred for graphitization. Our system is coupled also with an isotope ratio mass spectrometer (IRMS), which measures the δ13C and δ15N of that gas. Some less routine pretreatment protocols require the production of gaseous samples and prevent the possibility of using the EA-AGE3 system, as the EA is used for solid samples only. In order to use that system, including the measurements of stable isotopes, we developed a glass tube cracker that connects to the EA. The device is routinely used in our laboratory and is mainly built from Swaglok catalog parts. We show that the background (blank) levels of a marble standard are indistinguishable between using the cracker and burning solid marble using the EA. We further demonstrate that the δ13C values are consistent and that the extraction efficiency when using the device is above 93%. Full descriptions, drawings, and working protocol are supplied. [ABSTRACT FROM AUTHOR]

There has been a recent increasing interest in Zn–air batteries as an alternative to Li-ion batteries. Zn–air batteries possess some significant advantages; however, there are still problems to solve, especially related to the tuning of the properties of the air–cathode which should carry an inexpensive but efficient bifunctional oxygen reduction (ORR) and oxygen evolution (OER) reaction electrocatalyst. Biochar can be an alternative, since it is a material of low cost, it exhibits electric conductivity, and it can be used as support for transition metal ions. Although there is a significant number of publications on biochars, there is a lack of data about biochar from raw biomass rich in hemicellulose, and biochar with a small number of heteroatoms, in order to report the pristine activity of the carbon phase. In this work, activated biochar has been made by using corncobs. The biomass was first dried and minced into small pieces and pyrolyzed. Then, it was mixed with KOH and pyrolyzed for a second time. The final product was characterized by various techniques and its electroactivity as a cathode was determined. Physicochemical characterization revealed that the biochar had a hierarchical pore structure, moderate surface area of 92 m2 g−1, carbon phase with a relatively low sp2/sp3 ratio close to one, and a limited amount of N and S, but a high number of oxygen groups. The graphitization was not complete while the biochar had an ordered structure and contained significant O species. This biochar was used as an electrocatalyst for ORR and OER in Zn–air batteries where it demonstrated a satisfactory performance. More specifically, it reached an open-circuit voltage of about 1.4 V, which was stable over a period of several hours, with a short-circuit current density of 142 mA cm−2 and a maximum power density of 55 mW cm−2. Charge–discharge cycling of the battery was achieved between 1.2 and 2.1 V for a constant current of 10 mA. These data show that corncob biochar demonstrated good performance as an electrocatalyst in Zn–air batteries, despite its low specific surface and low sp2/sp3 ratio, owing to its rich oxygen sites, thus showing that electrocatalysis is a complex phenomenon and can be served by biochars of various origins. [ABSTRACT FROM AUTHOR]

Oak-tree-based white charcoals were subjected to high-temperature heat treatment at up to 2400 °C to analyze changes in their surface morphology and internal structure using scanning electron microscopy and transmission electron microscopy. When the treatment temperature was increased, micropores became smaller and disappeared, but macropores and mesopores remained, resulting in an increase in average pore size. At treatment temperatures of 2000 °C or higher, all the pores disappeared and the internal structure changed into a dense graphite-like structure. The X-ray diffraction patterns of charcoals heat-treated at 1800 °C or higher in an argon atmosphere exhibited a sharp peak near 2θ = 26.5°, and Raman spectroscopy showed clear D and 2D bands near 1360 and 2680 cm−1, respectively, indicating that carbon graphite crystals were developing. At 2400 °C for 10 min., the interlayer distances (d002 and d100), Lc and La of the graphite crystallites were 0.34, 0.21, 23.00, and 6.13 nm, respectively. The presence of the D band and the IG/(IG + ID) ratio confirmed that the newly developed structure was turbostratic. The Brunauer–Emmett–Teller (BET) adsorption isotherm of the as-received charcoals exhibited peculiar characteristics in which Types I and IV were mixed. This result is due to low-pressure hysteresis, in which nitrogen is embedded in the crevices of charcoal during adsorption and is hardly desorbed during desorption. This low-pressure hysteresis disappeared as increasing the temperature, the adsorption isotherm of charcoal treated at 2400 °C was Type II, and the specific surface area was 8.45 m2/g, indicating that the charcoal was completely transformed to nonporous graphite. [ABSTRACT FROM AUTHOR]

Blue hydrogen produced from fossil fuels is recognized as a promising large‐scale technology for realizing the hydrogen economy. Membrane‐based separation is emerging as a viable alternative to traditional hydrogen purification technologies. Here, we present a facile strategy for fabricating carbon molecular sieve (CMS) hollow fiber membranes containing uniformly dispersed palladium (Pd) nanoparticles. The Pd nanoparticles, anchored in the carbon strands of CMS membranes, induced the carbon matrix toward a more ordered structure arrangement through a synergistic effect of entropy‐driven size exclusion and acceleration of graphitization. As a result, the doped Pd nanoparticles facilitated the formation of ultramicropores <3.3 Å in the CMS membranes, which enabled a precise molecular sieving ability between H2 and CO2 with H2/CO2 selectivity up to 247. Furthermore, the membrane presented good mixed gas separation performances and was stable for over 250 h under simulated harsh industrial conditions. [ABSTRACT FROM AUTHOR]

Transition metal‐coordinated nitrogen sites on carbon catalysts (M‐N‐C) hold potential for CO2 electroreduction (CO2ER), but optimal morphology and active sites are unclear. We introduce a novel approach, developing zeolitic imidazolate framework‐8 (ZIF‐8)‐derived carbon catalysts with Fe‐N and graphitic‐N sites (Fe2‐NC) via molecular confinement and thermal activation. Fine‐tuning ZIF‐8 size and activation temperature yielded 44.98% active N sites. The 300 nm Fe2‐NC catalyst displayed outstanding CO2‐to‐CO conversion, with a 170 mV overpotential and 94.3% Faradaic efficiency at −0.5 V, outperforming state‐of‐the‐art materials. Enhanced CO2ER kinetics and conductivity contributed to this superiority. Results highlight the correlation between maximum CO Faradaic efficiency and cumulative Fe‐N/graphitic‐N sites, dependent on size and activation. The 300 nm Fe2‐NC in a gas diffusion electrode‐loaded flow cell achieved a 15.3‐fold CO partial current density increase. In a Zn‐CO2 battery, the 300 nm Fe2‐NC demonstrated a peak power density of 0.618 mW cm−2, showcasing energy storage potential. [ABSTRACT FROM AUTHOR]

The selective oxidation of 5‐(Hydroxymethyl)furfural (HMF) to 2,5‐Furandicarboxylic acid (FDCA) is highly attractive for the production of renewable monomers as substitute for fossil‐based monomers. To achieve a sustainable synthesis, we report on advances for a base‐free approach, reducing waste from the process, using air as oxidant and heterogeneous catalysts. Various Carbon‐based supports, which can be bio‐sourced and cost‐efficient, for Pt particles were investigated as they allow for an easy reuse and at the end‐of‐life Pt can be recycled to enable a closed cycle. Commercially available supports with varying properties, which might replace the base, were studied with Pt particles of similar size and loading. Significant differences in the catalytic activity were observed, which were correlated with the O‐functionalities and graphitization degree of the supports derived from Raman spectroscopy, temperature‐programmed desorption, and X‐ray photoelectron spectroscopy. An activated carbon (Norit ROX) rich in quinone/pyrone‐type groups and a carbon black‐based catalyst with graphene‐layers pushed the efficiency with enhanced FDCA‐yields enabling the complete substitution of the homogeneous base. This allows to circumvent the base in this process which together with high selectivity, air as oxidant, a reusable catalyst, and the use of bio‐based feedstock contributes to the sustainability of the production of renewable monomers. [ABSTRACT FROM AUTHOR]

Electrocatalyst, as a key factor for electrocatalytic CO 2 reduction reaction (CO 2 RR) has been extensively researched for its high activity and selectivity, cost-effectiveness, and straightforward preparation methods. A series of N-doped porous carbons, used as CO 2 RR electrocatalysts, were prepared from solid waste lignin with the assistance of ZnCl 2 as activator and melamine as nitrogen source. The addition of N atoms to lignin-derived carbon materials can significantly improve the performance of CO 2 RR compared with undoped lignin-derived carbon materials. The texture of the N-doped lignin-derived carbon materials, including specific surface area, pore structure, and the type of active sites, can be finely tuned by adjusting the carbonization temperature from 700 °C to 1000 °C. N-doped lignin-derived carbon materials obtained under 800 °C exhibitd the highest CO selectivity because of its high ratio of mesoporosity and suitable active sites promoting the conversion of CO 2 to CO. The N-doped lignin-derived carbon materials obtained under 900 °C had the largest range of adjustable syngas H 2 /CO ratios from 2.3 to 8.0 due to its sensitivity to the applied voltages. The CO 2 RR performance of N-doped lignin-derived carbon materials were influenced by multiple physicochemical properties, including the configuration of the N-dopant, porosity and degree of graphitization. This work not only offers a fresh perspective on the utilization of lignin-derived carbon materials, but also presents an efficient method for creating carbon-based electrocatalysts for CO 2 RR by using naturally abundant precursors. [Display omitted] • N-doped lignin-derived carbon materials were synthesized as CO 2 RR electrocatalysts. • The influence of the carbonization temperature on the CO 2 RR performance of lignin-derived carbon materials was studied. • The impact of type of heteroatoms on the CO 2 RR performance of lignin-derived carbon materials was investigated. • The CO 2 RR performance of N-doped lignin-derived carbon materials were influenced by multiple physicochemical properties. [ABSTRACT FROM AUTHOR]

Porous carbons with concurrently high specific surface area and electronic conductivity are desirable by virtue of their desirable electron and ion transport ability, but conventional preparing methods suffer from either low yield or inferior quality carbons. Here we developed a lithiothermal approach to bottom–up synthesize highly meso–microporous graphitized carbon (MGC). The preparation can be finished in a few milliseconds by the self-propagating reaction between polytetrafluoroethylene powder and molten lithium (Li) metal, during which instant ultra-high temperature (>3000 K) was produced. This instantaneous carbon vaporization and condensation at ultra-high temperatures and in ultra-short duration enable the MGC to show a highly graphitized and continuously cross-coupled open pore structure. MGC displays superior electrochemical capacitor performance of exceptional power capability and ultralong-term cyclability. The processes used to make this carbon are readily scalable to industrial levels. Porous carbons with high specific surface area and electronic conductivity are of interest for their electron and ion transport ability. Here authors use ultra-high temperature reactions of Li metal and polytetrafluoroethylene to make graphitized porous carbon for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

The composite material SBC-Fe-x with sludge and Fe3+ was developed by different calcination temperatures (600, 700, and 800 °C) for the removal of tetracycline (TC). The adsorption rates of SBC-Fe-600, SBC-Fe-700, and SBC-Fe-800 were 77.5%, 89%, and 91%, respectively. Furthermore, the Langmuir model indicated that the maximum adsorption capacity of SBC-Fe-700 (157.93 mg/g) was three times greater than that of SBC-Fe-600. The conclusions were confirmed by a series of characterizations that SBC-Fe-700 showed a larger specific surface area, well-developed pore structure, rich oxygen-containing functional groups and a high degree of graphitization. The results of pH experiments indicated the broad applicability of SBC-Fe-700 for TC adsorption. In addition, SBC-Fe-700 suggested outstanding performance in different water environments. This work produced a feasible adsorbent for the removal of TC, and a new direction for sludge resource utilization was proposed. [ABSTRACT FROM AUTHOR]

In the field of wearable thermoelectric generators, graphene-based materials have attracted attention as suitable candidates due to their low material costs and tunable electronic properties. However, their high thermal conductivity poses significant challenges. Low thermal conductivity due to porous structure of the laser-induced graphene, combined with its affordability and scalability, positions it as a promising candidate for thermoelectric applications. In this study, thermoelectric properties of the laser-induced graphene (LIG) on polyimide and their dependence on structural modifications of LIG were investigated. Furthermore, it was shown that increasing the laser scribing power on polyimide results in larger graphene flakes and a higher degree of graphitization. Electrical conductivity measurements indicated an increase with increasing laser power, due to a higher degree of graphitization, which enhances charge carrier mobility. Our findings reveal that LIG exhibits p-type semiconducting behavior, characterized by a positive Seebeck coefficient. It was shown that increasing laser power increased the Seebeck coefficient and electrical conductivity simultaneously, which is attributed to a charge carrier energy filtering effect arising from structures occurred on the graphene flakes. Moreover, the porous structure of LIG contributes to its relatively low thermal conductivity, ranging between 0.6 W/m·K and 0.85 W/m·K, which enhances the thermoelectric performance of LIG. It has been observed that with increasing laser power, the figure of merit for laser-induced graphene can be enhanced by nearly 10 times, which holds promising applications for laser-induced graphene due to the tunability of its thermoelectric performance by changing laser parameters. [ABSTRACT FROM AUTHOR]

[Display omitted] • The FeCoNiMnV HEA/ N -CNTs catalyst was prepared by a one-step pyrolysis. • The multi-metal synergy favored the ORR catalytic performance. • Clustered N -CNTs had rich shared boundaries and interstitial space to expedite the charge/mass transfer. • The built battery showed high OCV, large power density and long-term durability. Efficient and stable oxygen reduction reaction (ORR) catalysts are essential for constructing reliable energy conversion and storage devices. Herein, we prepared noble metal-free FeCoNiMnV high-entropy alloy supported on nitrogen-doped carbon nanotubes (FeCoNiMnV HEA/ N -CNTs) by a one-step pyrolysis at 800 °C, as certificated by a set of characterizations. The graphitization degree of the N -CHTs was optimized by tuning the pyrolysis temperature in the control groups. The resultant catalyst greatly enhanced the ORR characteristics in the alkaline media, showing the positive onset potential (E onset) of 0.99 V and half-wave potential (E 1/2) of 0.85 V. More importantly, the above FeCoNiMnV HEA/ N -CNTs assembled Zn-air battery exhibited a greater open-circuit voltage (1.482 V), larger power density (185.12 mW cm−2), and outstanding cycle stability (1698 cycles, 566 h). This study provides some valuable insights on developing sustainable ORR catalysts in Zn-air batteries. [ABSTRACT FROM AUTHOR]

In this study, diamond/silicon carbide (SiC) composites were prepared by liquid Si infiltration. The effects of the infiltration temperature on the densification, diamond graphitization, and thermal conductivity of the composites were investigated. The effects of the diamond content on the thermal conductivity and bending strength were also explored. X‐ray diffraction and Raman spectroscopy detected diamond graphitization at an infiltration temperature of 1480°C. Almost no graphitized diamond was observed due to reactions between silicon and carbon to form SiC at infiltration temperatures higher than 1480°C. As the infiltration temperature increased, graphitized diamond was consumed, and the thermal conductivity of the composite rose. The thermal conductivity and bending strength of the composites depended on the diamond content, reaching values of 257 W/m K and 237 MPa, respectively, for the sample with a diamond content of 17.9 vol.%. The higher bending strength was mainly ascribed to the high diamond content and well‐bonded interface. [ABSTRACT FROM AUTHOR]

Silicon oxycarbide (SiOC) is a promising anode material for lithium‐ion batteries, owing to the high capacity and superior structural stability. However, the application of SiOC anode is limited by its low conductivity and poor rate performance. Here, SiOC anodes were prepared by the pyrolysis of silicone resin (RSN‐217) at different temperatures (700, 850, 1000, and 1150° C), and the effect of graphitization degree and Si─O─C network on the electrochemical performance of SiOC anodes was investigated. The elemental and structural characteristics of the pyrolyzed SiOC ceramics at different temperatures were inspected using a broad spectrum of characterization techniques, and electrochemical performance testing methods, such as cyclic voltammetry and galvanostatic charge/discharge, were conducted on SiOC anode. SiOC‐1000 showed excellent electrochemical performance due to the highest graphitization degree of free carbon phase and the highest content of SiO2C2 and SiO3C units. Considerable research effort laid a foundation for exploring the lithium storage mechanism of SiOC anode. [ABSTRACT FROM AUTHOR]

A series of metal- and silica-containing carbon-based nanocomposites were synthesized by pyrolysis of a resorcinol–formaldehyde polymer modified with metal oxide/silica nanocomposites (MxOy/SiO2, where M = Mg, Mn, Ni, Cu and Zn) via the thermal oxidative destruction of metal acetates adsorbed on highly dispersed silica (A380). The concentration of metals was 3.0 mmol/g SiO2. The phase composition and morphological, structural and textural properties of the carbon materials were analyzed by X-ray diffraction, SEM, Raman spectroscopy and low-temperature N2 adsorption. Thermal decomposition under a nitrogen atmosphere and in air was analyzed using TG–FTIR and TG–DTG–DSC techniques to determine the influence of the filler on the decomposition process. The synthesized composites show mesoporous structures with high porosity and narrow pore size distributions. It could be shown that the textural properties and the final composition of the nanocomposites depend on the metal oxide fillers of the precursors. The data obtained show that nickel and copper promote the degree of graphitization and a structural order with the highest porosity and largest specific surface area of the hybrid composites. The good adsorption properties of the obtained materials were shown for the recovery of p-chlorophenol and p-nitrophenol from aqueous solutions. [ABSTRACT FROM AUTHOR]

A suite of slate samples collected along a 2 km transect crossing the Lishan fault in central Taiwan were evaluated to assess the role of ductile deformation in natural graphitization at lower greenschist facies metamorphic conditions. The process of natural aromatization, or graphitization, of an organic precursor is well established as a thermally driven process; however, experimental studies have shown that the energy provided by deformation can substantially reduce the activation energy required for graphitization. This study provides a natural example of deformation‐induced graphitization. A strain gradient approaching the Lishan fault was established by scanning electron microscope imaging and X‐ray diffraction analysis of phyllosilicates and quartz that showed an increase in the strength of slaty cleavage development via dissolution‐precipitation processes. Thermal conditions were constrained to be near isothermal using calcite‐dolomite geothermometry. Raman spectroscopic results from carbonaceous material, including D1‐full width‐at‐half‐maximum (FWHM), G‐FWHM, Raman band separation (RBS), and a lesser‐known vibrational mode B2g‐FWHM, showed robust linear trends across the same sampling transect. However, the G‐FWHM parameter showed a trend opposite of that expected from thermally driven graphitization. The Raman results are interpreted to reflect a strain‐driven reduction in graphite crystallite size (decrease in G‐FWHM) but improvement in structural ordering in individual coherent domains. A multiple linear regression with an R2 value of 0.92 predicts the graphite D1‐FWHM values from the XRD‐derived ratio of muscovite populations and muscovite microstrain, demonstrating the concomitant recrystallization of silicates and carbonaceous material across the strain gradient, despite the disparate processes accommodating the deformation. This study demonstrates the role of deformation in natural graphitization and provides a new perspective on the use of graphite as a geothermometer in strongly deformed greenschist facies rocks. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) is a common material of choice in catalysis, as it is a suitable support material for many catalytic reactions. In this work, the effect of cobalt nanoparticles on activated carbon derived from a biomass waste, peach stone, is reported. The presence of cobalt during heat treatments at 900 °C under reductive (H2) and inert (He) atmospheres resulted in the appearance of an intense 2D band in the Raman spectra, indicating a high degree of graphitization. Temperature-programmed reduction and desorption experiments were conducted to evaluate the activation reactions. Quenched solid density functional theory (QSDFT) analysis using N2 adsorption data revealed that cobalt increased pore development in the samples, regardless of the atmosphere (reductive or inert) used. [ABSTRACT FROM AUTHOR]

Unburned carbon from fly ash and its graphitization products (at temperatures of 2400 and 3000°C) were tested using scanning electron microscope (SEM), X-ray diffraction (×RD) and micro-Raman spectroscopy. The same tests were also carried out for synthetic and natural graphite. Various morphological forms of products with a high degree of graphitization, such as spheroidal graphite, hexagonal plates, column plates, and jagged-edge films were identified in the sample of unburned carbon annealed at 3000°C. The product of thermal treatment at the temperature of 3000°C has the interlayer spacing d002 value characteristic for semigraphite. With increasing temperature the number of crystallites in stack N, their height Lc002 and aromaticity fa increases. The degree of G graphitization of annealed samples increases more than twice with increasing temperature. With the increase of the temperature the aliphatic chains are decomposed and the aromatic systems are reconstructed, so the degree of internal structure order increases. The Raman examinations showed that the structural parameters determined for the graphite and carbonizate samples after thermal treatment at the temperature of 3000°C are equal in the standard deviation range. [ABSTRACT FROM AUTHOR]

Lithium-oxygen (Li-O2) batteries have been regarded as an expectant successor for next-generation energy storage systems owing to their ultra-high theoretical energy density. However, the comprehensive properties of the commonly utilized organic salt electrolyte are still unsatisfactory, not to mention their expensive prices, which seriously hinders the practical production and application of Li-O2 batteries. Herein, we have proposed a low-cost all-inorganic nitrate electrolyte (LiNO3−KNO3−DMSO) for Li-O2 batteries. The inorganic nitrate electrolyte exhibits higher ionic conductivity and a wider electrochemical stability window than the organic salt electrolyte. The existence of K+ can stabilize the O2− intermediate, promoting the discharge process through the solution pathway with an enlarged capacity. Even at an ultra-low concentration of 0.01 M, the K+ can still remain stable to promote the solution discharge process and also possess a new function of inhibiting the dendrite growth by electrostatic shielding, further enhancing the battery stability and contributing to the long cycle lifetime. As a result, in the 0.99 M LiNO3−0.01 M KNO3−DMSO electrolyte, the Li-O2 batteries exhibit prolonged cycling performance (108 cycles) and excellent rate performance (2 A·g−1), significantly superior to the organic salt one. [ABSTRACT FROM AUTHOR]

In this study, novel durable flame-retardant lyocell fibres were designed by the addition of phosphorylated cellulose and physical blending of montmorillonite (MTT) within the fibres. The influences of phosphorylation and MTT blending on the flame retardancy of lyocell fibres were investigated. Additionally, the synergistic effects of the two flame retardant methods were also discussed. Furthermore, phosphorylated cellulose and MTT-filled lyocell fibres were prepared, and their flame retardancy was measured. Phosphorylation (limiting oxygen index (LOI) > 28%) was found to improve the flame retardancy of the lyocell fibres; nevertheless, excessive phosphorylation decreased the crystallinity of the cellulose and decreased the mechanical strength of the fibres. Montmorillonite was added to the lyocell fibres to achieve durable flame retardancy, whereas the LOI was less than 24%. Interestingly, lyocell fibres with LOIs greater than 28% and strengths greater than 2.0 cN/dtex could be obtained from the phosphorylated cellulose with MTT filling. The thermogravimetric (TG) and TG-infrared (TG-IR) experimental results showed that MTT played a role in the condensed-phase flame retardancy, while phosphorylated cellulose played a role in the gas-phase and condensed-phase flame retardancy. The Raman test results showed that the combination of MTT and phosphorylated cellulose enhanced the graphitization degree of the residue char. In our study, a novel flame-retardant method for the preparation of lyocell fibres with permanent flame retardancy and high tensile strength was developed; moreover, our results contribute to the development of industrial-grade fabrication of new flame-retardant fibre materials. [ABSTRACT FROM AUTHOR]

Alkyl hypophosphate flame retardants have aroused intense research interests in flame retardancy of polymers owing to the combined effect of gas phase and condensed phase. In this work, aluminum diisobutyl hypophosphate (APBA) was incorporated into polyethylene glycol terephthalate (PET) to investigate its flame retardant effect and mechanism. PET achieved a V‐2 level in UL‐94, with a low LOI of 21.2%. In contrast, PET/APBA‐15% composites showed a 51% increase of LOI value and a V‐0 level, accompanied with the significant reduction of melt droplets. Gas phase analysis by Py‐GC/MS and TG‐FTIR indicated that the phosphorous free radicals and nonflammable gases were generated during the cracking of APBA, resulting in the radical quenching and dilution of combustible gas. Condensed phase analysis by SEM, Raman, and XPS results revealed that APBA could effectively facilitate the formation of dense char layers consisting of aluminophosphate and graphitic structures due to the interaction with PET matrix. The compact barrier layer could insulate heat and inhibit the volatilization of combustible materials, leading to improved flame retardant properties. Furthermore, the introduction of APBA increased the melt viscosity of PET/APBA composites according to rheological analysis, which further promoted the formation of a char barrier layer to further enhance the flame retardant properties. Highlights: Aluminum diisobutyl hypophosphate is used as an efficient flame retardant for PET.The flame retardant can degrade to release the phosphorous free radicals.The flame retardant can interact with the PET matrix and promote the charring. [ABSTRACT FROM AUTHOR]

Although lithium–sulfur (Li–S) batteries have attracted strong consideration regarding their fundamental mechanism and energy applications, the inferior cycling performance and low reaction rate caused by the "shuttling effect" and the sluggish reaction kinetics of lithium polysulfides (LiPSs) impede their practical application. In this work, graphitic C3N4 (g-C3N4) assembled with highly-dispersed nitrogen-containing carbon quantum dots (CQDs) is designed as a cooperative catalyst to accelerate the reaction kinetics of LiPS conversion, the precipitation of Li2S during discharging, and insoluble Li2S decomposition during the charging process. Meanwhile, the introduction of CQDs improves the conductivity of the g-C3N4 substrate, showing great significance for the construction of high-performance electrocatalysts. As a result, the as-obtained composite shows efficient adsorption and electrochemical conversion of LiPSs, and the Li–S batteries assembled with CQDs/g-C3N4 exhibit an initial specific capacity of 1300.0 mA h g−1 at the current density of 0.1C and retain 582.3 mA h g−1 after 200 cycles. The electrode with the modified composite displays a greater capacity contribution of Li2S precipitation (175.7 mA h g−1), indicating an enhanced catalytic activity of g-C3N4 decorated by CQDs. The rational design of CQDs/g-C3N4 as a sulfur host could be an effective strategy for developing high performance Li–S batteries. [ABSTRACT FROM AUTHOR]

The cost-effectiveness and abundance of sodium make sodium-ion batteries a compelling alternative to lithium-ion batteries. The hurdle is adapting the widely used graphite anodes in lithium-ion batteries for use in sodium-ion battery anodes, given the larger size of sodium. Macroporous carbon materials emerge as promising anode candidates for sodium-ion batteries due to their favorable electrolyte penetration and structural stability. In this research, an economical and readily available high-temperature coal pitch serves as the precursor for the anode material. Sodium chloride acts as the templating agent, while phosphorus atoms are intentionally introduced through disodium hydrogen phosphate to induce defects. The phosphorus-doped macroporous carbon demonstrates noteworthy specific capacity and cycling stability, even under high current density conditions, making it a viable choice for application in sodium-ion batteries: after 1000 cycles at a current density of 5 A g−1, the reversible specific capacity still reaches 135 mA h g−1 with a capacity retention rate of 94.4%; after increasing the current density to 10 A g−1, the reversible specific capacity still exceeds 100 mA h g−1 after 3500 cycles. [ABSTRACT FROM AUTHOR]

Heterostructured Fe2O3/Fe7S8 hollow fibers were rationally designed and synthesized via the electrospinning technique, followed by a calcination process and sulfuration treatment. Benefitting from the synergistic effect of the hollow structure and the built-in electric field induced by the heterostructure, the as-prepared Fe2O3/Fe7S8 composite anode exhibits high specific capacity (947 mA h g−1 after 100 cycles at 0.2 A g−1), excellent rate capability, and long-term cycling stability (730 mA h g−1 after 1000 cycles at 1 A g−1). [ABSTRACT FROM AUTHOR]

[Display omitted] • Regeneration of waste graphite by using surfactant assisted methanesulfonic acid. • The purity and recovery rate of regenerated graphite reaches 99.7% and 98.0%. • This method can protect the graphite structure under impurity removal conditions. • Regenerated graphite exhibits excellent electrochemical performance. With the vigorous development of the new energy industry, the use of lithium-ion batteries (LIBs) is growing exponentially, and the recycling of spent LIBs has gradually become a research hotspot. Currently, recycling both cathode and anode materials of LIBs is important to environmental protection and resource recycling. This research reports a method of efficient purification and high-quality regeneration of graphite from spent LIBs by surfactant-assisted methanesulfonic acid (MSA). Under the optimal conditions (0.006 mol/L sodium dodecyl sulfonate, 0.25 mol/L MSA, 10 vol% hydrogen peroxide, liquid–solid ratio of 30:1 mL/g, 60 °C, 1.5 h), the purity of the regenerated graphite was 99.7 %, and the recovery efficiency was 98.0 %. The regenerated graphite showed the characteristics of small interplanar spacing, high degree of graphitization, a small number of surface defects, and excellent pore structure, which was closer to commercial graphite. Furthermore, the regenerated graphite electrode exhibited superior rate performance and cycling stability with a high specific capacity of 397.03 mAh/g after 50 cycles at 0.1C and a charge–discharge efficiency of 99.33 %. The recovery of anode graphite beneficial for resource utilization, environmental protection, and cost control throughout the entire production chain. [ABSTRACT FROM AUTHOR]

A polarized light microscope (PLM) was utilized to examine the optical textures of mesophase pitch (MP) and MP-derived fibers, which aimed to reveal the arrangement and orientation characteristics of pitch molecules and to clarify the evolution and transformation mechanism of carbonaceous microcrystalline from pitch fibers to graphitized fibers. The results found that there were distinct optical textures in MP, where one side exhibited a transition from a flattening plane to a mountain-like undulating plane. This transition corresponded to the arrangement of pitch molecules, resembling stacked lamellar structures reminiscent of curved paper. Meanwhile, the optical textures of fibers revealed that the blue substance was wrapped around the red grain-like domains in the longitudinal section and confirmed that the red part belonged to the pyridine insoluble fraction of MP and the blue part belonged to its pyridine-soluble fraction. After graphitization, the red part was transformed into graphite sheets and the blue part was transformed into an amorphous carbon layer which was wrapped around the graphite sheets, forming a carbonaceous microcrystalline package-like bag. Therefore, this study provided a comprehensive interpretation of the structural evolution mechanism of MP and MP-derived fibers based on their macro-optical textures and micro-nanostructures. [ABSTRACT FROM AUTHOR]

Lignin is an abundant biomass resource that can be converted to carbon nanotubes (CNTs) via floating catalyst chemical vapor deposition (FCCVD). This study investigates how Fe catalyst properties impact the synthesis, structure, and properties of lignin-derived CNTs. During CNTs synthesis via FCCVD, increasing the ferrocene concentration yields more CNT products, but the catalyst efficiency declines, as evidenced by the appearance of shorter CNTs and more Fe residue in the product. Transmission electron microscopy reveals that the size and morphology of Fe nanoparticles strongly influence CNT structure, defects, and graphene layer alignment in the nanotube sidewalls during growth. High-temperature graphitization effectively removes residual catalysts from the CNTs and improves their crystallinity and conductivity. During graphitization from 1600 to 2800 °C, the graphene interlayer spacing decreases, while the Raman IG/ID ratio increases from 3.16 to 8.08, electrical conductivity increases from 4.05 × 104 to 5.92 × 104 S m–1, and thermal conductivity can be enhanced from 31.20 to 50.49 W m–1 K–1. Correlating catalyst characteristics with CNT structure evolution provides insights into the controlled synthesis of tailored biomass-derived CNTs with specific structures and properties. [ABSTRACT FROM AUTHOR]

This paper studies the morphological and structural changes that occur during the graphitization of synthetic diamond powder (with highly faceted edges) and micropowder during heat treatment in air at temperatures up to 1000°C and in a vacuum at temperatures up to 1600°C. The most developed facets of the original diamond crystals are the octahedral {111} and cubic {100} faces. It is established that graphitization begins from the vertices and edges of crystals. {111} faces are more susceptible to graphitization than {100} faces. The morphological analysis of graphitized diamond AC160 in air helps us to study the kinetics of graphitization: the growth of dendritic graphite crystals and the formation of "graphitization pits" on the surface of diamond facets. It is shown for the first time that graphite of different shapes is formed on different diamond faces at different rates; thus, on the {111} faces graphite forms and grows in the form of triangles, and on the {100} faces, in the form of squares. At a high temperature, the volumetric graphitization of diamond particles is observed, accompanied by their destruction, mainly in the growth stages. [ABSTRACT FROM AUTHOR]

Carbon coating layers have been found to improve the catalytic performance of transition metals, which is usually explained as an outcome of electronic synergistic effect. Herein we reveal that the defective graphitic carbon, with a unique interlayer gap of 0.342 nm, can be a highly selective natural molecular sieve. It allows efficient diffusion of hydrogen molecules or radicals both along the in‐plane and out‐of‐plane direction, but sterically hinders the diffusion of molecules with larger kinetic diameter (e.g., CO and O2) along the in‐plane direction. As a result, poisonous species lager than 0.342 nm are sieved out, even when their adsorption on the metal is thermodynamically strong; at the same time, the interaction between H2 and the metal is not affected. This natural molecular sieve provides a very chance for constructing robust metal catalysts for hydrogen‐relevant processes, which are more tolerant to chemical or electrochemical oxidation or CO‐relevant poisoning. [ABSTRACT FROM AUTHOR]

The study investigates the effects of the physicochemical properties of engine sump soot on the frictional characteristics of its contaminated engine oils. Moreover, the relationship between soot physicochemical properties and its frictional characteristics was also discussed. The results showed that the properties of the two kinds of lubricating oil (A, B) used in diesel engines affect the properties of engine sump soot (Soot-A, Soot-B), i.e. Soot-A showing smaller aggregate size, larger primary particle diameter, more disordered nanostructure, and higher functional content than those of Soot-B. For both soot particles, as the amount of soot particles added to the formula oil went up from 1 wt.% to 2 wt.%, the wear scar diameter (WSD) and friction coefficient of the wear spot increased. For both soot particles, the main wear form of the steel ball wear area was abrasive wear (more than 90%), accompanied by a small amount of plastic deformation and pitting (less than 2%). With the same amount of soot in lubricating oil, soot with a higher degree of graphitization, low oxygen content and low reactivity may cause smaller WSD and lighter wear. Moreover, a larger soot accumulation would result in deeper plow marks and pits in the abrasion areas. [ABSTRACT FROM AUTHOR]

The modification of nanodiamond (ND) surfaces has significant applications in sensing devices, drug delivery, bioimaging, and tissue engineering. Precise control of the diamond phase composition and bond configurations during ND processing and surface finalization is crucial. In this study, we conducted a comparative analysis of the graphitization process in various types of hydrogenated NDs, considering differences in ND size and quality. We prepared three types of hydrogenated NDs: high-pressure high-temperature NDs (HPHT ND-H; 0–30 nm), conventional detonation nanodiamonds (DND-H; ~5 nm), and size- and nitrogen-reduced hydrogenated nanodiamonds (snr-DND-H; 2–3 nm). The samples underwent annealing in an ultra-high vacuum and sputtering by Ar cluster ion beam (ArCIB). Samples were investigated by in situ X-ray photoelectron spectroscopy (XPS), in situ ultraviolet photoelectron spectroscopy (UPS), and Raman spectroscopy (RS). Our investigation revealed that the graphitization temperature of NDs ranges from 600 °C to 700 °C and depends on the size and crystallinity of the NDs. Smaller DND particles with a high density of defects exhibit a lower graphitization temperature. We revealed a constant energy difference of 271.3 eV between the sp-peak in the valence band spectra (at around 13.7 eV) and the sp3 component in the C 1s core level spectra (at 285.0 eV). The identification of this energy difference helps in calibrating charge shifts and serves the unambiguous identification of the sp3 bond contribution in the C 1s spectra obtained from ND samples. Results were validated through reference measurements on hydrogenated single crystal C(111)-H and highly-ordered pyrolytic graphite (HOPG). [ABSTRACT FROM AUTHOR]

[Display omitted] Lignin-derived carbon materials are widely used as electrode materials for supercapacitors. However, the electrochemical performance of these materials is limited by the surface chemistry and pore structure characteristics. Herein, a novel and sustainable strategy was proposed to prepare heteroatom-doped lignin-derived carbon material (Fe-NLC) with well-developed pore size distributions and enhanced graphitization structure via a facile lignin-Fe coordination method followed by carbonization. During carbonization, Fe3+ in lignin-metal complexes evolve into nanoparticles, which act as templates to introduce porous structures in carbon materials. Also, the lignin-Fe coordination structure endows the material with a higher graphitization during carbonization, thereby improving the structural properties of the carbon materials. Due to the removal of Fe 3 O 4 template, the obtained Fe-NLC possessed reasonable pore distribution and nitrigen/oxygen (N/O) functional groups, which can improve the wettability of materials and introduce pseudocapacitance. Accordingly, Fe-NLC possesses a notable specific capacitance of 264 F/g at 0.5 A/g. Furthermore, a symmetric supercapacitor Fe-NLC//Fe-NLC with a high voltage window (1.8 V) was constructed. The symmetric supercapacitor exhibits a maximum energy density of 15.97 Wh/kg at 450 W/kg, demonstrating well application prospects. This paper proposes a novel approach for preparing carbon materials via lignin-metal coordination to provide an alternative way to explore sustainable and low-cost energy storage materials. [ABSTRACT FROM AUTHOR]

Wireless passive sensors based on surface acoustic wave (SAW) provide a good solution for the measurement demand under high temperature and harsh conditions. SiBCN ceramics have excellent mechanical properties at high temperature and semiconductor behavior, making them potential for electrode of SAW sensors. To achieve the target conductivity, a series of SiBCN and SiNiBCN coatings are prepared by polymer derived ceramics (PDC) method and the influence of microstructure on the conductivity of the coatings is discussed. The results show that the conductivity of the SiBCN coatings is affected by both the content of free carbon and the degree of graphitization. The introduction of Ni leads to the formation of Ni 2 Si conductive microcrystals at lower temperatures and catalyzes the graphitization of the carbon phase, so that the SiNiBCN coatings show lower electrical resistivity. The amount of the metal conductive phase and the graphitization degree of the carbon phase increase with the pyrolysis temperature, resulting in decrease of the SiNiBCN coatings resistivity. [ABSTRACT FROM AUTHOR]

Zinc-promoted nickel catalysts on Ultra-Stable Y (USY) zeolite support are tested for their efficacy towards methane pyrolysis. The un-promoted catalyst obtained a conversion of 65.8%, which dropped to 57.3% at the end of the experiment. However, addition of 5 wt% Zn promoter increased the conversion to 67.7%, with no discernible loss in activity after 60 h on-stream. XPS analysis indicated evidence of electronic interaction between the Ni and Zn metals, and the addition of Zn caused a reduction in the metal-support interactions of the catalyst as revealed in TPR and XRD analyses. The catalytic activity of the 50Ni–5Zn/USY also remained completely stable for 60 h even after the operating temperature was increased to 650 °C and the partial pressure of methane in the inlet increased to 80%, at a High gas hour space velocity of 120 L/gcat.h. Analysis of the spent 50Ni–5Zn/USY catalyst revealed the presence of Ni–Zn carbides that may have contributed to the increase in activity, as well as the formation of large quantities of highly graphitic and ordered multi-walled carbon nanotubes produced by the tip-growth mechanism which have been shown to prolong catalyst lifetime on-stream. • Electronic interactions between Ni and Zn enhanced catalytic activity. • Zinc catalyst doping weakened metal-support interaction and increased NiO particle size. • 5% zinc loading raised methane conversion to 67.7% which remained stable for 60 h. • Addition of Zn increased the degree of carbon graphitization. • The observed tip growth carbon mechanism improved catalyst stability. [ABSTRACT FROM AUTHOR]

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The study explored the graphitization of wood through two distinct methods: a high-temperature approach at 2400 °C and a low-temperature technique at 1400 °C using a catalyst. The graphitization properties were assessed by conducting thermal experiments at various temperatures (1100 °C, 1400 °C, 1800 °C, 2000 °C, and 2400 °C), both with and without a catalyst. The development of graphite lattices was quantitatively analyzed using an array of techniques: X-ray diffractometer (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared spectroscopy (FTIR). The XRD analysis highlighted temperature-dependent changes in lattice parameters (d002, La, and Lc), while Raman spectroscopy tracked alterations in the D to G peak ratio (D/G) with temperature. An increase in temperature is correlated with a rise in the number of graphene layers and the degree of graphitization. Notably, the process of graphite lattice formation varied across the experimental temperature spectrum. The use of a catalyst resulted in a reduced d002 spacing, signifying an enhanced degree of graphitization. Moreover, the catalyst promoted a consistent and smooth graphitization process throughout the heating stages. In contrast, graphitization without a catalyst occurred at higher temperatures, specifically between 1800 °C and 2000 °C, with the d002 value stabilizing around 0.338 nm. The catalyst proved instrumental in transforming the initial structure into well-ordered graphite at lower temperatures. This investigation underscores the potential and benefits of employing a catalyst to generate high-quality graphite from wood at reduced temperatures, paving the way for sustainable and economically viable applications of this material. [ABSTRACT FROM AUTHOR]

To gain insights into the spectroscopy characteristics from coal to graphite, we investigated different metamorphic degrees of coal-based graphite which were collected from Hunan Province China. In this paper, by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, graphite with different metamorphism degrees has been characterized to explore the evolution of macromolecular structure of organic matter during graphitization. The results show that with the increase of metamorphism degree, the 002-diffraction peak of the series of samples gradually shrinks and narrows, and the peak intensity becomes stronger, indicating that the microcrystalline structure gradually becomes regular and ordered. As the degree of graphitization increase, the uniformity of particle size in coal samples observed gradually increases, and the morphology becomes more regular, transitioning from disordered and irregular shapes to a structured large-scale flake pattern. The crystallinity improves, and the massive coal particles gradually coalesce into large plate crystals, with the inter-particle pores gradually closing. The graphite structure becomes increasingly evident. The FTIR spectra show that as the degree of graphitization increases, the peak at 1,581 cm−1 corresponding to C=C vibrations gradually intensifies. Some inert functional groups are retained throughout the graphitization process. The pores between coal particles gradually close, and the morphology of graphite particles becomes more regular and ordered. Additionally, during the graphitization process, structures similar to carbon nanotubes may develop. Throughout the structural transformation from coal macromolecules to graphite crystals, the size of the sp2 planar domains in single-layer graphene increases, and the lattice structure of carbon atoms gradually enlarges. These findings contribute to a comprehensive understanding of the properties and characteristics of coal-derived graphite, and can provide theoretical reference and basis for the metallogenic mechanism of coal-derived graphite and the efficient utilization of coal.

Pressurized carbonization is known to improve carbon content and create textural changes in resultant carbon compared to conventional (atmospheric) carbonization. However, further studies investigating the impact of these carbonization methods on the graphitic quality of the carbon precursors have not been explored extensively. This study investigates the influence of carbonization methods on the graphitization behavior of soft and hard carbons using a three-model system: phenolic resole (hard carbon), polyvinyl chloride (PVC) (soft carbon), and a 50:50 blend of resole and PVC. Carbonization was conducted under autogenic pressure (AGP) and atmospheric pressure (APP) at 500 °C for 5 h, followed by high-temperature treatment at varying temperatures. Various techniques, including X-ray diffraction and Raman spectroscopy showed hard carbon precursors exhibited improved properties under AGP carbonization such as larger crystallite size, sharp crystalline peaks, lower ID/IG ratio, and narrow G-full width half-maximum, an indication of improved crystallinity by lowering amorphous phase at high temperature. For soft carbon precursors, the method of carbonization did not impact the graphitization level. The most significant finding was the enhanced crystalline nature observed in hard carbon under AGP conditions, without the need for any catalyst. It shows the influence of pressure on improving the crystallinity of hard carbon precursors.

Nitrogen-containing carbons (NC) are a class of sustainable materials for selective CO2 adsorption. A versatile concept is introduced to fabricate flexible NC-based sensor architectures for room-temperature sensing of CO2 in a one-step laser conversion of primary films cast from abundant precursors. By the unidirectional energy impact in conjunction with depth-dependent attenuation of the laser beam, a layered sensor heterostructure with a porous transducer and active sensor layer is formed. Comprehensive microscopic and spectroscopic cross-sectional analyses confirm the preservation of the high content of imidazolic nitrogen in the sensor. The performance is optimized in terms of material morphology, chemical composition, and surface chemistry to achieve a linear relative resistive response of up to ΔR/R0 = −14.3% (10% of CO2). Thermodynamic analysis yields ΔadsH values of −35.6 and 34.1 kJ·mol−1 for H2O and CO2, respectively. The sensor is operable even in humid environments (e.g., ∆R/R0,RH = 80% = 0.53%) and shows good performance upon strong mechanical deformation.

The hydrogen evolution reaction (HER) and Zn dendrites growth are two entangled detrimental effects hindering the application of aqueous Zn batteries. The alloying strategy is studied to be a convenient avenue to stabilize Zn anodes, but there still lacks global understanding when selecting reliable alloy elements. Herein, it is proposed to evaluate the Zn alloying elements in a holistic way by considering their effects on HER, zincphilicity, price, and environmental‐friendliness. Screening selection sequence is established through the theoretical evaluation of 17 common alloying elements according to their effects on hydrogen evolution and Zn nucleation thermodynamics. Two alloy electrodes with opposite predicted effects are prepared for experimental demonstration, i.e., HER‐inhibiting Bi and HER‐exacerbating Ni. Impressively, the optimum ZnBi alloy anode exhibits one order of magnitude lower hydrogen evolution rate than that of the pure Zn, leading to an ultra‐long plating/stripping cycling life for more than 11 000 cycles at a high current density of 20 mA cm−2 and 81% capacity retention for 170 cycles in a Zn‐V2O5 pouch cell. The study not only proposes a holistic alloy selection principle for Zn anode but also identifies a practically effective alloy element. [ABSTRACT FROM AUTHOR]