Carbothermal Reduction Reaction Research Articles

Confined Flash Pt1/WCx inside Carbon Nanotubes for Efficient and Durable Electrocatalysis.

Exploiting cost-effective hydrogen evolution reaction (HER) catalysts is crucial for sustainable hydrogen production. However, currently reported nanocatalysts usually cannot simultaneously sustain high catalytic activity and long-term durability. Here, we report the efficient synthesis and activity tailoring of a chainmail catalyst, isolated platinum atom anchored tungsten carbide nanocrystals encapsulated inside carbon nanotubes (Pt1/WCx@CNTs), by confined flash Joule heating technique. The instantaneous carbothermal reduction reaction enables the millisecond formation of Pt1/WCx nanostructures from CNT-encapsulated polyoxometalates, where nanotubes serve as both heating conductors and robust chainmails. The Pt1/WCx@CNTs exhibit prominent catalytic performance toward acid HER with a low overpotential of 45.2 mV at 10 mA cm-2 and long-term durability over 500 h of continuous running. Mechanism studies reveal the strong metal-support interaction on Pt1/WCx optimizes the charge redistribution at the Pt1-W2C interface and the hydrogen adsorption/desorption behavior. This study offers a potential avenue for ultrafast and activity-controllable synthesis of highly stable single-atom catalysts.

Ablation resistance and high-temperature insulation capacity of TiB2-B4C modified Al-coated carbon fibre/boron phenolic resin ceramizable composites

Ablation resistance and high-temperature insulation capacity of TiB2-B4C modified Al-coated carbon fibre/boron phenolic resin ceramizable composites

Preparation of (Zr0.25Hf0.25Ta0.25Nb0.25)C high-entropy ceramic nanopowders via liquid-phase precursor route at a low temperature of 1500 °C

Preparation of (Zr0.25Hf0.25Ta0.25Nb0.25)C high-entropy ceramic nanopowders via liquid-phase precursor route at a low temperature of 1500 °C

Energy consumption in the selective reduction of iron from ilmenite concentrate

The main pyrometallurgical methods are single–stage electric melting and a two-stage method according to the “tubular furnace – melting unit” scheme. Both processing schemes involve the use of carbon as a reducing agent, which in turn leads to the formation of iron metal products and titanium oxide concentrate based on anosovite – Ti3O5. Reducing firing of ilmenite concentrate allows selectively reducing iron from ilmenite concentrate with both carbon and hydrogen to produce soft iron and a concentrate of titanium oxides with a rutile – TiO2 structure. It is shown that the process of carbothermic reduction of iron from ilmenite at a temperature of 1300 ℃ proceeds by the reaction: 3FeTiO3 + + 4C = 3Fe + Ti3O5 + 4CO. At a temperature of 900 ℃, the reduction of iron from ilmenite with carbon and hydrogen proceeds by the reactions: FeTiO3 + C = Fe + TiO2 + CO, FeTiO3 + H2 = Fe + TiO2 + H2O. The results of calculating energy costs for carbothermic reduction reactions at 1300 and 900 ℃ and hydrogen at 900 ℃ are presented. According to the calculation results, the lowest amount of costs is fixed when reducing iron with hydrogen at a temperature of 900 ℃ and amounts to 215.81 kJ. At the same temperature and carbon reduction, the total energy consumption is 341.29 kJ. The total energy consumption for the reaction of ilmenite with carbon at a temperature of 1300 ℃ is 484.51 kJ. When comparing the calculation results, it was found that the reduction of iron with hydrogen at a tempera-ture of 900 ℃ is 1.58 times less expensive than carbothermic reduction at the same temperature, and 2.25 times than carbothermic reduction at a temperature of 1300 ℃. Carbothermic reduction of iron at a temperature of 1300 ℃ re-quires even greater energy consumption due to heating the charge to a higher temperature and partial reduction of tita-nium to a lower oxide – Ti3O5 anosovite

Recovery of NMC-lithium battery black mass by microwave heating processes

Recovery of NMC-lithium battery black mass by microwave heating processes

Interface migration and alloying mechanism of Fe and P for ferrophosphorus alloy production during the carbothermic reduction of phosphorite

Interface migration and alloying mechanism of Fe and P for ferrophosphorus alloy production during the carbothermic reduction of phosphorite

Facile Fabrication of Melamine/MXene/FeNi‐PBA Composite Derived Multi‐Interface Magnetic Carbon Foam for High‐Efficiency Microwave Absorption

AbstractThe development of novel materials with high‐efficiency microwave absorption is crucial for mitigating the adverse impacts of electromagnetic pollution. In this study, MXene and FeNi Prussian blue analogs (PBA) are assembled onto a melamine foam using self‐assembly and in situ growth technique. Subsequently, magnetic carbon foam, comprising FeNi alloys, TiN and carbon with various morphologies, is synthesized via carbothermal reduction reaction. The surface morphology electromagnetic properties are significantly influenced by the pyrolysis temperature. The results revealed that the magnetic carbon foam composite demonstrated an effective microwave absorption bandwidth of 4.72 GHz at a thickness of only 1.5 mm, with a minimum reflection loss of −24.83 dB at 1.3 mm. The outstanding microwave absorption performance can be attributed to the 3D conductive network formed by N‐doped carbon, as well as the contributions from polarization loss, magnetic loss, and suitable impedance matching. Furthermore, the corresponding absorber coating demonstrated a maximum reduction value of radar cross‐section (RCS) by 13.16 dB m2. This research offers novel insights for the development of lightweight and efficient low‐filled electromagnetic composite for broadband microwave absorption.

Microstructure evolution and failure mechanism of 2D Cf/SiBCN–ZrB2 composite at elevated temperatures

Microstructure evolution and failure mechanism of 2D Cf/SiBCN–ZrB2 composite at elevated temperatures

Microstructure characterization and growth mechanism of ZrC whiskers prepared by precursor transformation method

Microstructure characterization and growth mechanism of ZrC whiskers prepared by precursor transformation method

Preparation and characterization of zirconium carbide nano powder by hydrothermal and carbothermal reduction methods

Preparation and characterization of zirconium carbide nano powder by hydrothermal and carbothermal reduction methods

Carbothermal reduction between MOF-derived carbon and spent battery powder for metal recovery: Thermogravimetric behavior and kinetic analysis

Carbothermal reduction between MOF-derived carbon and spent battery powder for metal recovery: Thermogravimetric behavior and kinetic analysis

Fabrication of the SiC/HfC Composite Aerogel with Ultra-Low Thermal Conductivity and Excellent Compressive Strength.

Aerogels, as a new type of high-temperature-resistant insulation material, find extensive application in aerospace, high-temperature industrial furnaces, new energy batteries, and various other domains, yet still face some limitations such as inadequate temperature resistance and pronounced brittleness. In this work, SiC/HfC composite aerogels were prepared through a combination of sol-gel method, atmospheric pressure drying technique, and carbothermal reduction reaction. The effects of different molar ratios, calcination time, and temperatures on the microstructural features and physicochemical properties of the resulting SiC/HfC composite aerogels were investigated. The aerogel exhibited an elevated BET-specific surface area of 279.75 m2/g, while the sample displayed an extraordinarily low thermal conductivity of 0.052 W/(m·K). Most notably, the compressive strength reached an outstanding 5.93 MPa after a carbonization temperature of 1500 °C, far exceeding the values reported in prior aerogel studies. This research provided an innovative approach for advancing the development of carbide aerogels in the realm of high-temperature applications.

An efficient method of preparing Si–Fe–Al–Ca alloy from coal gasification fine slag via plasma smelting and alternating current magnetic field

It is of great significance to solve the environmental problems caused by the unreasonable treatment of coal gasification slag. This study successfully produced Si-Fe-Al-Ca alloy from low-carbon fine slag with petroleum coke as reducing agent in a plasma furnace with an alternating current magnetic field, which solved the problem of the high reactivity requirement of carbon reductant for plasma smelting. The optimum carbon content of the mixed low-carbon fine slag and petroleum coke is 105% of the theoretical value. As the strength of the alternating current magnetic field increased (from 0% to 100% of the maximum power), the yield of the alloy (from 25.46% to 58.19%) and the recovery ratios of each element (Si, Fe, Al, Ca, Ti) increased. In addition, as the magnetic field strength increased, the pores inside the alloy became smaller, the composition of the alloy became more homogeneous, and a better separation of the alloy from the slag was observed. The main composition of the alloy at the strongest alternating current magnetic field is Si: 51.14wt%, Fe: 28.41wt%, Al: 9.14wt%, Ca: 7.15wt%, Ti: 2.03wt%. We attribute the enhanced smelting effect of the alternating current magnetic field to the resistive heat and Lorentz force produced by the induced current. In addition, the skin effect concentrated the induced current on the surface of the oxide particles and carbon particles, which increased the temperature of the reaction interface and promoted the carbothermal reduction reaction.

Fire-resistant and thermal insulation performance of SiC nanofiber batt fabricated from cotton fiber batt

Fire-resistant and thermal insulation performance of SiC nanofiber batt fabricated from cotton fiber batt

Kinetics of microwave carbothermal reduction of Sb2O3: Isothermal and non‐isothermal microwave thermogravimetric analysis

AbstractKinetics of antimony production via carbothermal reduction of Sb2O3–carbon powder–NaCl mixture using microwave and conventional heating was investigated to identify the dominant controlling mechanism. Results of conventional heating revealed the temperature range of conventional carbothermal reduction reaction is 500°C to 800°C, with the average activation energy of each stage being 81.97 kJ/mol (α = 0.1–0.5), 65.17 kJ/mol (α = 0.5–0.75), and 69.86 kJ/mol (α = 0.75–1.0), respectively. In the microwave field, the carbothermal reduction reaction of raw materials can be completed at 600°C to obtain antimony, and the weight loss data of the carbothermal reduction process were recorded for the first time. The above results show that the microwave field enhanced the interfacial chemical effect, accelerated the interfacial diffusion from the metal phase to the oxide phase, and reduced the activation energy of the carbon thermal reduction process to 6.85 kJ/mol. The growth index of antimony grain growth process is estimated to be 4.33, controlled by the surface diffusion. These data provide a reliable theoretical basis for studying the reduction reactions of minerals in microwave fields.

Large-scale fabrication and characterization of SiC nanowire thermal insulation paper by a traditional handcraft paper-making process

Large-scale fabrication and characterization of SiC nanowire thermal insulation paper by a traditional handcraft paper-making process

Theoretical and experimental study of the mechanism for preparation of SiC nanowires by carbothermal reduction

Theoretical and experimental study of the mechanism for preparation of SiC nanowires by carbothermal reduction

Functional Composite Dual-Phase In Situ Self-Reconstruction Design for High-Energy-Density Li-Rich Cathodes.

The unique anionic redox mechanism provides, high-capacity, irreversible oxygen release and voltage/capacity degradation to Li-rich cathode materials (LRO, Li1.2Mn0.54Co0.13Ni0.13O2). In this study, an integrated stabilized carbon-rock salt/spinel composite heterostructured layers (C@spinel/MO) is constructed by in situ self-reconstruction, and the generation mechanism of the in situ reconstructed surface is elucidated. The formation of atomic-level connections between the surface-protected phase and bulk-layered phase contributes to electrochemical performance. The best-performing sample shows a high increase (63%) of capacity retention compared to that of the pristine sample after 100 cycles at 1C, with an 86.7% reduction in surface oxygen release shown by differential electrochemical mass spectrometry. Soft X-ray results show that Co3+ and Mn4+ are mainly reduce in the carbothermal reduction reaction and participate in the formation of the spinel/MO rock-salt phase. The results of oxygen release characterized by Differential electrochemical mass spectrometry (DEMS) strongly prove the effectiveness of surface reconstruction.

DETERMINATION OF THE MASS BALANCE OF HIGH-CARBON FERROCHROME IN A SUBMERGED ARC FURNACE

In this study, it is aimed to establish one-day mass balance of the materials entering into and leaving from a submerged arc furnace (SAF) where high-carbon ferrochrome is produced in it. The SAF is used in a plant located in Elazig, Turkey. For this purpose, measurements were taken from the SAF during one month by obtaining the necessary permits from the plant. In addition to these measurements, chemical reactions in the SAF are defined based on the information obtained from the literature and the plant. Chrome ore and rich slag are raw materials for furnace; as auxiliary raw materials, coke, coal, electrode paste, quartzite, and bauxite are fed. The product and the waste coming out of the SAF are high-carbon ferrochrome, slag, flue gas, and fly ash. Samples were taken from each raw material and auxiliary raw materials fed into the SAF and the products, then the chemical composition analysis was carried out by using an X-ray fluorescence (XRF) device. The reactions that take place in the SAF are carbothermic reduction reactions. Metal oxides (Cr<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub>, etc.) react with carbon and are reduced as MO + C = M + CO (M = metal). As a result of this study, the mass amounts of the materials entering into and leaving from the SAF established a balance.

Preparation of ceramifiable and ablatively resistant epoxy resins by microphase structure modulation of silicones

Preparation of ceramifiable and ablatively resistant epoxy resins by microphase structure modulation of silicones