Metal Carbon Research Articles

A New Sight on the Influence of Molten Salt in the Preparation of (Ta, Nb, Ti) C Nanopowder

The molten salt method (MSM) is an effective approach for obtaining multicomponent carbide nanopowders at low temperatures. However, the presence of impurities limits its application in the lower‐temperature domains. To address this issue, (Ta, Nb, Ti) C nanopowders are fabricated by the MSM at 1100–1400 °C, and the dual‐route synthesis mechanism is revealed. Results indicate that the synthesis temperature of pure (Ta, Nb, Ti) C nanopowders can be decreased with the addition of molten salt, which is determined by the formation and decomposition of the intermediates. During the synthesis process, the molten salt can provide the liquid‐phase environment for the combination reaction between metal powders and carbon, facilitating the formation of homogeneous and nanosized powders. Meanwhile, the molten salt reacts with impurities to generate intermediates including KTaO3 and K1.04Ti8O16 at low temperatures, which subsequently form carbides through thermal reduction. This transformation can decrease the energy barrier of the synthesis process.

Synthesis and characterization of coprecipitated layered NCM oxide as cathode for sodium-ion batteries: Kinetics and hydrodynamics studies

Interest in the development of high-performance sodium-ion batteries (SIBs) as a sustainable alternative to lithium-ion batteries (LIBs) for emerging energy storage systems has motivated to delve into a novel approach for the synthesis of layered transition metal oxide (LTMO) type cathode for SIBs batteries. In this study, we introduce novel chemical synthesis method that diverges from traditional methodologies reported till date. Rather than relying on sulfur, nitrate, or acetate metal precursor salts, we employ metal carbonate salt coupled with oxalic acid as a chelating agent, and sodium carbonate as a precipitating agent. This novel chemistry enhances the microstructure of the cathode material inherited from its precursor exhibiting spherical morphology, influence on the electrochemical properties, bestowing the material with high specific capacity, extended cycle life, and an elevated charge–discharge rate. The primary focus of this work centers on a comprehensive investigation of the hydrodynamic and kinetics aspects of the co-precipitation reaction, guided by the principles of chemical engineering. The effects of key parameters such as impeller speed, impeller type, and scale-up effects on the co-precipitation process have been systematically explored. This research introduces insights into optimizing reaction conditions such as pH, reaction temperature, metal precursor salt ratio, precipitating agent, through rigorous experimentation and characterization reports. The notable effect of precipitating agent on morphology has been demonstrated by electron microscopy images. The kinetics study shows the activation energy of 8.9 kJ mol−1 depicts the reaction is controlled by mass transfer resistance and to overcome this effect, impeller type and speed plays significant role and experimentation results shows the axial mixing pattern created by pitched blade impeller is effective to improvise electrochemical properties. The synthesized cathode material exhibits remarkable electrochemical properties, including tap density of approximately 1.3 g cc−1 with reversible capacity of 215 mAh g−1, along with excellent cyclic stability (90 %) over 60 cycles. Furthermore, it shows the high energy density up to 1300 Wh/L and a rapid charge–discharge rate. These findings contribute to the advancement of SIBs technology and offer promising prospects for future researchers to efficient development of high-performance energy storage solutions.

Promotion of active H-assisted CaCO3 conversion for integrated CO2 capture and methanation

Carbonate hydrogenation is a new path for the conversion of metal carbonate with potentially lower energy consumption and CO2 emissions comparing to the traditional thermal decomposition, and the integrated CO2 capture and utilization (ICCU) represents its latest development. However, the slow hydrogenation rate of carbonate at low temperatures is one key scientific challenge for applications. Herein, we report an acidity regulation approach to prepare ZrO2-doped Ni/CaO dual-function material with good CO2 capacity, fast and highly selective conversion below 600 °C for integrated CO2 capture and utilization by methanation (ICCU-methanation). Experiments and DFT calculations show that the introduction of ZrO2 as acid sites effectively strengthens *H adsorption and reduces the formation barrier of intermediate *COOH during carbonate hydrogenation. Thus, Ni10(ZrO2)10CaO80 exhibits a CH4 STY of 14.1 mmol∙min−1∙gNi−1 at 550 °C, 6 times higher than the reference DFM. Furthermore, the presence of O2 in flue gas is observed to have no effect on ICCU-methanation, but steam could delay the in-situ methanation. Long-term cyclic test shows that the optimal Ni10(ZrO2)5CaO85 has a stable CO2 capacity of 7.5 mmol ∙gDFM−1, 98 % CO2 conversion and 95.5 % CH4 selectivity under flue gas containing both steam and O2 at 600 °C, suggesting a good potential to be applied in ICCU-methanation.

Effective removal of Cr (VI) from an aqueous solution using a carbon coated NiFe2O4 nano-adsorbent

Exploration of cubic ferrites for chromium removal is ongoing. Ferrites offer a promising avenue for chromium removal because of their unique properties, high surface area, magnetic recoverability, and potential for surface modifications to enhance adsorption capacities. Herein, the work highlights the synthesis of carbonaceous nickel ferrite (NiFe2O4/C) through an inert ambient pyrolysis process, where metal acetylacetonates are used as the sources of metal ions and carbon. The synthesized NiFe2O4/C was successfully characterized for its structure and morphology using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy, Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. The study confirmed that, the size of nanostructure was of ∼29 nm, with a surface area of 56.925 m2/g, pore volume of 0.085 cc/g with type IV hysteresis loop. The regular spherical shape was observed through FESEM, and a carbon coating was evident and confirmed from TEM. Synthesized NiFe2O4/C was efficiently used for the Cr (VI) removal, it was found that at an equilibrium time of 60 min, nearly 85% of the chromium was removed using 0.01 g of adsorbent at native pH and efficiency was further improved by lowering the pH. The investigation further examined the isotherm and kinetics models. The material was regenerated for 5 cycles with a removal percentage of 57%.

Ionic-storage capacitance enhanced by a self-assembled CoO-Nafion nanocoating on single-walled carbon nanotubes

We introduce a novel approach for enhancing ion-storage capabilities through the self-assembled formation of ternary nanowires, consisting of a CoO-and-Nafion nanocomposite encasing metallic single-walled carbon nanotubes (SWNTs). These nanowires highlight the indispensable role of the conductor-semimetallic SWNT-CoO heterojunction in expediting the redox reaction kinetics of the CoO while the Nafion component facilitates the transport of hydroxide ions. Consequently, supercapacitors comprising the ternary nanowires deliver the specific capacitance of calculated 18.84 mF cm−2, five times higher than those obtained at the counterpart devices that lack Nafion and/or CoO. This self-assembly method precisely organizes functional components within the nanowires, aligning with electrochemical principles to optimize charge transfer and minimize concentration gradients for improved electrochemical polarization. Our function-enhanced ternary nanowires, together with their straightforward synthetic process, promise an alternative opportunity for formulating high-performance ion-storage electrodes and thus pave the way for their application in next-generation supercapacitor technologies.

A high-throughput approach for assessing antiscaling performance during mineral precipitation from seawater and hard water

The undesired precipitation of minerals from solution poses challenges in various industrial and domestic applications, including water treatment, desalination, dishwashers and boilers. To mitigate this, threshold inhibitors - small quantities of water-soluble additives—are commonly employed to inhibit the precipitation of inorganic phases. However, concerns about the persistence of traditional additives like phosph(on)ates) in natural environments and stricter regulations warrant the development of more sustainable alternatives. We present a high-throughput approach using a UV-Vis spectrophotometer and automated data analysis to assess the scale inhibiting potential of numerous candidates and their combinations. The robustness and versatility of this method were validated by measuring the kinetics of alkaline-earth metal carbonates precipitating from simulated hard waters and seawaters across an extended range of experimental parameters. This approach allows for straightforward evaluation and quantification of each antiscaling additive’s effectiveness and operational range, enabling direct comparison of different additives and blends of additives. Moreover, it facilitates the study of scaling processes in both bulk solutions and at liquid/solid interfaces. By providing a rapid and reliable means of screening potential additives and formulations, our versatile toolbox will expedite the identification of effective scale inhibitors, thereby contributing to the advancement of sustainable practices in various industries reliant on water treatment and mineral precipitation control.

Fluorescent multichannel sensor array based on three carbon dots derived from Tibetan medicine waste for the quantification and discrimination of multiple heavy metal ions in water.

Afluorescent multichannel sensor array has been establishedbased on three carbon dots derived from Tibetan medicine waste for rapid quantification and discrimination of six heavy metal ions. Due to the chelation between metal ions and carbon dots (CDs), this fluorescence "turn off" mode sensing array can quantify six metal ions as low as "μM" level. Moreover, the six heavy metal ions display varying quenching effects on these three CDs owing to diverse chelating abilities between each other, producing differential fluorescent signals for three sensing channels, which can be plotted as specific fingerprints and converted into intuitive identification profiles via principal component analysis (PCA) and hierarchical cluster analysis (HCA) technologies to accurately distinguish Cu2+, Fe3+, Mn2+, Ag+, Ce4+, and Ni2+ with the minimum differentiated concentration of 5μM. Valuably, this sensing array unveils good sensitivity, exceptional selectivity, ideal stability, and excellent anti-interference ability for both mixed standards and actual samples. Our contribution provides a novel approach for simultaneous determination of multiple heavy metal ions in environmental samples, and it will inspire the development of other advanced optical sensing array for simultaneous quantification and discrimination of multiple targets.

Semianisotropic Interfacial Potential for Interfaces between Metal and 2D Carbon Allotrope

Semianisotropic Interfacial Potential for Interfaces between Metal and 2D Carbon Allotrope

Synthesis, microstructure, properties of nonstoichiometry high entropy carbide (MoNbTaTiW)C4.5

AbstractA dense, fine‐grained, and toughened nonstoichiometry high entropy carbide (HEC) (MoNbTaTiW)C4.5 was synthesized via a two‐step way of carbothermal reduction‐solid solution using metal oxides and carbon. The effects of carbothermal reduction temperature, sintering temperature, and carbon content on the phase, microstructure, mechanical and thermal properties of (MoNbTaTiW)C4.5 were studied. The results showed dense and single phase (MoNbTaTiW)C4.5 were synthesized through reduction of metal oxides at 1600°C and sintered at and above 1950°C by spark plasma sintering. Reduced carbon content and higher solid solution temperature were beneficial to obtain dense HECs with better mechanical properties. With a carbon content of 90%, a reduction temperature of 1600°C, a holding time of 20 min, and a sintering temperature of 1950°C, the as‐synthesized (MoNbTaTiW)C4.5 showed a higher fracture toughness (5.2 MPa·m1/2). Besides, the (MoNbTaTiW)C4.5 showed a low thermal conductivity (5.9 W/m·K, at room temperature).

First-principles study on the structure, mechanical and thermodynamic properties of (Ti, Hf, Nb, Ta)C high-entropy carbide ceramics

High-entropy carbide ceramics (HECCs) have demonstrated extraordinary properties and broad application potential. However, the action mechanisms of metallic elements on the properties have not been understood in depth. In this study, the structural stability and the mechanical and thermodynamic properties of (Ti, Hf, Nb, Ta)C HECCs across a broad composition spectrum were systematically analyzed based on the density functional theory and Debye–Grüneisen model. The crystal structure was constructed and validated through experimental testing. The mechanical properties such as elastic moduli, ductility, hardness, and Poisson's and Pugh's ratios were calculated. Furthermore, the temperature dependence of bulk moduli, thermal expansion coefficients, and heat capacities of the HECCs were investigated. To interpret the elastic and toughening mechanisms of non-equiatomic HECCs, the electronic structures were investigated. The results indicate that the HECCs with a single solid solution phase of the FCC rock-salt structure are thermodynamically stable. The HECCs containing higher Nb and Ta contents have greater strength and stiffness, and those containing higher Ti and Hf contents exhibit greater hardness and brittleness than the equiatomic HECC. In addition, non-equiatomic HECCs containing higher Nb and Ta contents have larger bulk moduli and lower linear thermal expansion coefficients, which can be attributed to the stronger covalent interaction among metallic elements and carbon. This study is expected to have an impact on designing ideal HECCs for high-temperature applications under extreme environments.

Genomic characterization of a novel ureolytic bacteria, Lysinibacillus capsici TSBLM, and its application to the remediation of acidic heavy metal-contaminated soil

Soil heavy metal contamination is an essential challenge in ecological and environmental management, especially for acidic soils. Microbially induced carbonate precipitation (MICP) is an effective and environmentally friendly remediation technology for heavy metal contaminated sites, and one of the key factors for its realization lies in the microorganisms. In this study, Lysinibacillus capsici TSBLM was isolated from heavy metal contaminated soil around a gold mine, and inferred to be a novel ureolytic bacteria after phylogenomic inference and genome characterization. The urease of L. capsici TSBLM was analyzed by genetic analysis and molecular docking, and further applied this bacteria to the remediation of Cu and Pb in solution and acidic soils to investigate its biomineralization mechanism and practical application. The results revealed L. capsici TSBLM possessed a comprehensive urease gene cluster ureABCEFGD, and the encoded urease docked with urea at the lowest binding energy site (ΔG = −3.43 kcal/mol) connected to three amino acids threonine, aspartic, and alanine. The urease of L. capsici TSBLM is synthesized intracellularly but mainly functions extracellularly. L. capsici TSBLM removes Cu/Pb from the solution by generating heavy metal carbonates or co-precipitating with CaCO3 vaterite. For acidic heavy metal-contaminated soil, the carbonate-bound states of Cu and Pb increased significantly from 7 % to 16 % and from 23 % to 35 % after 30 days by L. capsici TSBLM. Soil pH improved additionally. L. capsici TSBLM maintained the dominant status in the remediated soil after 30 days, demonstrating good environmental adaptability and curing persistence. The results provided new strain resources and practical application references for the remediation of acidic heavy metal contaminated soil based on MICP.

Evaluating electrocatalytic activities of Pt, Pd, Au and Ag-based catalyst on PEMFC performance: A review

This comprehensive review article highlights recent advancements of Pt and Pd-based electrocatalysts, covering Pt and Pd alloys, Pt-M and Pd-M core-shell structures, nanosize/nanostructure effects, addition of support material, doping effects, and post-treatment for the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) in Proton exchange membrane fuel cell (PEMFC). Additionally, it delves into other precious metals such as Gold (Au) and Silver (Ag) for ORR and HOR in PEMFC. The role and contribution of incorporating other elements or materials such as metal oxides, metal carbides, transition metal oxides, carbon support, and non-carbon support are thoroughly discussed. The most promising methods are also described, with a special emphasis on narrow particle size, nanostructure, and low loading of novel Pt- and Pd-based catalysts. Furthermore, the advantages and shortcomings of these catalysts for electrocatalysis are analyzed, along with the influence of the nanostructure and morphology of the electrocatalyst materials on electrochemical performance.

Comparative evaluation on wear resistance of metal sleeve, sleeve-free resin, and reinforced sleeve-free resin implant guide: An in vitro study.

In-office three-dimensional (3D) printers and metal sleeveless surgical guides are becoming a major trend recently. However, metal sleeve-free designs are reported to be more prone to distortion which might lead to variation in the inner diameter of the drill hole and cause deviation and inaccuracy in the placement of the implant. Carbon fiber nanoparticles are reported to improve the properties of 3D printing resin material in industrial application. The purpose of the study is to evaluate and compare the wear resistance of 3D-printed implant guides with metal sleeve, sleeve-free, and reinforced sleeve-free resin to the guide drill. A total of 66 samples with 22 samples in each group. Three groups including 3D-printed surgical guide with metal sleeve (Group A), without metal sleeve (Group B), an carbon fiber reinforced without metal sleeve (Group C) were included in the study. All samples were evaluated before sequential drilling and after sequential drilling using Vision Measuring Machine. The data were tabulated and statistically evaluated. The data obtained were statistically analyzed with one-way analysis of variance and posthoc test. The data obtained for wear observed in the samples showed that the wear was highest in Group B with a mean of 0.5036 ± 0.1118 and the least was observed in Group A with a mean of 0.0228 ± 0.0154 and Group C was almost similar to Group A with mean of 0.0710 ± 0.0381. The results showed there was a significant difference between Group B with Group A and C, respectively (P < 0.05). The results showed that there was no significant difference regarding the wear observed between Groups A and C (P > 0.05). The wear observed in the guide with a metal sleeve and carbon fiber reinforced without a metal sleeve was almost similar. The carbon fiber-reinforced guide showed better tolerance to guide drill equivalent to metal sleeve. Thus, carbon fiber nanoparticles reinforced in 3D printing resin have shown improved strength and can be used as a good replacement for a metal sleeve for an accurate placement of the implant.

Contact-driven deformation of metallic carbon nanotubes observed from an unconventional field effect

Contact-driven deformation of metallic carbon nanotubes observed from an unconventional field effect

The Sensitivity of Structure to Ionic Radius and Reaction Stoichiometry: A Crystallographic Study of Metal Coordination and Hydrogen Bonding in Barbiturate Complexes of All Five Alkali Metals Li-Cs.

A systematic study has been conducted on barbiturate complexes of all five alkali metals, Li-Cs, prepared from metal carbonates or hydroxides in an aqueous solution without other potential ligands present, varying the stoichiometric ratio of metal ion to barbituric acid (BAH). Eight polymeric coordination compounds (two each for Na, K, and Rb and one each for Li and Cs) have been characterised by single-crystal X-ray diffraction. All contain some combination of barbiturate anion BA- (necessarily in a 1:1 ratio with the metal cation M+), barbituric acid, and water. All organic species and water molecules are coordinated to the metal centres via oxygen atoms as either terminal or bridging ligands. Coordination numbers range from 4 (for the Li complex) to 8 (for the Cs complex). Extensive hydrogen bonding plays a significant role in all the crystal structures, almost all of which include pairs of N-H···O hydrogen bonds linking BA- and/or BAH components into ribbons extending in one dimension. Factors influencing the structure adopted by each compound include cation size and reaction stoichiometry as well as hydrogen bonding.

Plasma-Treated Cobalt-Doped Nanoporous Graphene for Advanced Electrochemical Applications

Metal–carbon nanocomposites are identified as key contenders for enhancing water splitting through the oxygen evolution reaction and boosting supercapacitor energy storage capacitances. This study utilizes plasma treatment to transform natural graphite into nanoporous few-layer graphene, followed by additional milling and plasma steps to synthesize a cobalt–graphene nanocomposite. Comprehensive structural characterization was conducted using scanning and transmission electron microscopy, X-ray diffraction, Raman spectroscopy, gas sorption analysis and X-ray photoelectron spectroscopy. Electrochemical evaluations further assessed the materials’ oxygen evolution reaction and supercapacitor performance. Although the specific surface area of the nanoporous carbon decreases from 780 to 480 m2/g in the transition to the resulting nanocomposite, it maintains its nanoporous structure and delivers a competitive electrochemical performance, as evidenced by an overpotential of 290 mV and a Tafel slope of 110 mV/dec. This demonstrates the efficacy of plasma treatment in the surface functionalization of carbon-based materials, highlighting its potential for large-scale chemical-free application due to its environmental friendliness and scalability, paving the way toward future applications.

Recent Developments in Two-Dimensional Carbon-Based Nanomaterials for Electrochemical Water Oxidation: A Mini Review

Water splitting is considered a renewable and eco−friendly technique for future clean energy requirements to realize green hydrogen production, which is, to a large extent, hindered by the oxygen evolution reaction (OER) process. In recent years, two−dimensional (2D) carbon−based electrocatalysts have drawn sustained attention owing to their good electrical conductivity, unique physicochemical properties, and excellent electrocatalytic performance. Particularly, it is easy for 2D carbon−based materials to form nanocomposites, which further provides an effective strategy for electrocatalytic applications. In this review, we discuss recent advances in synthetic methods, structure−property relationships, and a basic understanding of electrocatalytic mechanisms of 2D carbon−based electrocatalysts for water oxidation. In detail, precious, non−precious metal−doped, and non−metallic 2D carbon−based electrocatalysts, as well as 2D carbon−based confined electrocatalysts, are introduced to conduct OER. Finally, current challenges, opportunities, and perspectives for further research directions of 2D carbon−based nanomaterials are outlined. This review can provide significant comprehension of high−performance 2D carbon−based electrocatalysts for water-splitting applications.

Electron transfer in MOF-derived cobalt-magnesium oxide–carbon microsphere composite catalytic ozonation of thiamphenicol

Cobalt-magnesium oxide–carbon microsphere composite (Co-MgO-CMS), Cobalt-carbon nanosheet composite (Co-CNS), and magnesium oxide–carbon nanorod composite (MgO-CNR) were synthesized by the MOFs self-sacrificing template method. And they were used as the catalysts for catalytic ozonation of thiamphenicol (20 mg/L) in water at an initial pH of 7.0. The phase of Co-MgO-CMS is mainly composed of metallic cobalt, magnesium oxide and carbon according to X-ray diffraction and transmission electron microscopy analyses. Thiamphenicol removal efficiency is enhanced through Co-MgO-CMS catalytic ozonation (75.4 %, in 6 min), compared with those in ozonation alone (39.8 %), Co-CNS catalytic ozonation (43.2 %), MgO-CNR catalytic ozonation (65.1 %) and Mg-Co binary oxide (Mg2CoOy) catalytic ozonation (69.0 %). Self-increasing of solution pH, protonated hydroxyl groups and electron transfer on metallic Co and lattice Co2+ are advantageous for the ozone decomposition into reactive oxygen species in Co-MgO-CMS catalytic ozonation. Owing to the metallic Co in Co-MgO-CMS, the electron transfer ability of Co-MgO-CMS is better than that of Mg2CoOy according to the in situ electrochemical test. Moreover, electron transfers directly from metallic Co to ozone. While protonated hydroxyl groups are the key for electron transfer on lattice Co2+. A possible degradation pathway for thiamphenicol in Co-MgO-CMS catalytic ozonation is proposed according to the detected intermediates. This work provides insight into improvement on electron transfer ability of concerted acid-base catalyst in heterogeneous catalytic ozonation.

Bipolar Polymeric Protective Layer for Dendrite‐Free and Corrosion‐Resistant Lithium Metal Anode in Ethylene Carbonate Electrolyte

AbstractThe unstable interface between Li metal and ethylene carbonate (EC)‐based electrolytes triggers continuous side reactions and uncontrolled dendrite growth, significantly impacting the lifespan of Li metal batteries (LMBs). Herein, a bipolar polymeric protective layer (BPPL) is developed using cyanoethyl (−CH2CH2C≡N) and hydroxyl (−OH) polar groups, aiming to prevent EC‐induced corrosion and facilitating rapid, uniform Li+ ion transport. Hydrogen‐bonding interactions between −OH and EC facilitates the Li+ desolvation process and effectively traps free EC molecules, thereby eliminating parasitic reactions. Meanwhile, the −CH2CH2C≡N group anchors TFSI− anions through ion‐dipole interactions, enhancing Li+ transport and eliminating concentration polarization, ultimately suppressing the growth of Li dendrite. This BPPL enabling Li|Li cell stable cycling over 750 cycles at 10 mA cm−2 for 2 mAh cm−2. The Li|LiNi0.8Mn0.1Co0.1O2 and Li|LiFePO4 full cells display superior electrochemical performance. The BPPL provides a practical strategy to enhanced stability and performance in LMBs application.

Bipolar Polymeric Protective Layer for Dendrite-Free and Corrosion-Resistant Lithium Metal Anode in Ethylene Carbonate Electrolyte.

The unstable interface between Li metal and ethylene carbonate (EC)-based electrolytes triggers continuous side reactions and uncontrolled dendrite growth, significantly impacting the lifespan of Li metal batteries (LMBs). Herein, a bipolar polymeric protective layer (BPPL) is developed using cyanoethyl (-CH2CH2C≡N) and hydroxyl (-OH) polar groups, aiming to prevent EC-induced corrosion and facilitating rapid, uniform Li+ ion transport. Hydrogen-bonding interactions between -OH and EC facilitates the Li+ desolvation process and effectively traps free EC molecules, thereby eliminating parasitic reactions. Meanwhile, the -CH2CH2C≡N group anchors TFSI- anions through ion-dipole interactions, enhancing Li+ transport and eliminating concentration polarization, ultimately suppressing the growth of Li dendrite. This BPPL enabling Li|Li cell stable cycling over 750 cycles at 10 mA cm-2 for 2 mAh cm-2. The Li|LiNi0.8Mn0.1Co0.1O2 and Li|LiFePO4 full cells display superior electrochemical performance. The BPPL provides a practical strategy to enhanced stability and performance in LMBs application.