Binary Composites Research Articles

Asymmetric supercapacitor based on nano-flower Ni-Co-O/C electrodes

Ni-Co-O material is the most representative polymetallic compound and has exhibited excellent energy storage properties. However, the high cost of composite restricts the practical application of Ni-Co-O material. In this paper, a simple and low-cost method is used to grow Ni-Co-O/C nanoarrays directly on a conductive matrix. The results show that the three-dimensional nanoflower-like Ni-Co-O/C composite has better electrochemical performance than that of the nanosheet Co-O/C binary composite. This microstructure provides a shorter path for electron transport, making the material high electron transport efficiency. The specific capacitance of Ni-Co-O/C/AC asymmetric supercapacitor can reach 128.75 mF cm−2 at 2 mA cm−2. Under the condition of 20 mA cm−2, after 4000 cycles of charge and discharge, the capacitance retention rate is maintained at 99.8 %. This 3D flower-like structure not only helps provide an open framework and rapid ion diffusion, but also exposes more active sites and enhances charge storage performance. Ni-Co-O/C calcined in nitrogen shows more abundant defect structure and larger specific surface area, which is further conducive to Ni-Co-O/C electrodes to expose more active sites and enhance the rapid diffusion and reaction of electrolyte ions.

Biopolymer-metal composites for selective removal and recovery of waterborne orthophosphate

Orthophosphate (Pi) remediation from effluent serves to address global water security by preventing eutrophication. Herein, chitosan (C), alginate (Alg) and three respective metal systems (Fe3+, Al3+, Cu2+) were used to prepare binary (BMC) or ternary (TMC) metal composite adsorbents. Their physicochemical properties were analyzed through XPS, IR and TGA, while the adsorption properties of the composites were characterized via adsorption isotherms and single-point experiments in saline environmental water. Al-composites formed Al–O complexes, while Fe- and Cu-composites formed in the presence of the biopolymer backbone FeO(OH) and Cu2(OH)3NO3, respectively. While Al-composites showed the highest bound water fraction (up to 16%), the Cu-composites (Cu-TMC-N, CuC-BMC-N; where N = nitrate) revealed the lowest water content. Alginate-based binary composites showed slightly higher water content, as compared to ternary and binary chitosan composites. Among the four materials (Al-TMC-N, Fe-TMC-N, Cu-TMC-N and CuC-BMC-N), the Al-TMC showed the highest Pi selectivity over sulfate, along with high Pi removal-% even in a binary mixture (sulfate + orthophosphate) despite the presence of competitive anion species. Upon spiking saline groundwater samples with low Pi (5 mg/L) that contains 2060 or 6030 mg/g sulfate, Al-TMC-N showed the highest Pi selectivity, followed by Fe-TMC-N. This trend in adsorption of Pi among the various composites is understood based on the HSAB principle for the conditions employed in this study. Removal efficiencies of Pi above 60% in Well 1 (ca. 2000 mg/L sulfate) and above 30% in Well 3 (ca. 6030 mg/L sulfate). Herein, environmentally compatible and sustainable composite adsorbents were prepared that reveal selective Pi recovery from (highly) saline groundwater that can mitigate eutrophication in aqueous media.

Fabrication of 2D nanomaterial reinforced co-continuous binary blend composites for thermal management and EMI shielding applications

Fabrication of 2D nanomaterial reinforced co-continuous binary blend composites for thermal management and EMI shielding applications

A novel ternary Fe(III)-SrTiO3-GO nanocomposite for LED-light-driven photocatalytic degradation of norfloxacin antibiotic: Performance, mineralization ability, degradation pathway, and mechanistic insight

The widespread production and use of pharmaceutical antibiotics is wreaking havoc on the environment. To address this issue, a semiconductor photocatalyst with high photocatalytic efficiency must be developed in order to eliminate antibiotics from wastewater. Herein, an efficient ternary photocatalyst (Fe(III)-SrTiO3-GO) was synthesized by anchoring Fe(III) species and GO sheets over the surface of SrTiO3 nanocubes. The optimized (2Fe(III)-SrTiO3-10GO) nanocomposite displayed superior photoactivity by degrading 92.3 % of NOF within 120 min of LED light exposure in contrast with pristine SrTiO3, (33.6 %) and binary composites (SrTiO3-10GO) (68.5% ), (2Fe(III)-SrTiO3) (79.2% ). The meliorative performance is credited to synergic effects of GO (with high conductivity), SrTiO3 (specialized morphology) and Fe(III) species (IFCT effect) all together in the trio-hybrid that accelerated the transference and separation of photoinduced carriers, and extends the visible-light responsive range. (h+), (OH) were the predominant reactive species liable for the degradation process. Further, the plausible photocatalytic mechanism and degradation pathways of NOF were speculated with several intermediates identified. The current study provide a new perspective on construction of innovative, reusable and cost-effective photocatalyst based on transition metal ion and GO co-catalyzed metal titanates for wastewater remediation.

CdS/g-C3N4/Sm-BDC MOF nanocomposite modified glassy carbon electrodes as a highly sensitive electrochemical sensor for malathion

Malathion is an organophosphate pesticide widely used in agriculture, whose elimination is highly demanded by society. This work faces this challenge by the development of a novel electrochemical sensor via modifying a glassy carbon electrode (GCE) with sustainable Sm-BDC MOFs and their corresponding novel binary and ternary composites combined with CdS and g-C3N4 for the detection of malathion. Different characterization techniques indicate the successful synthesis of desired composite materials, with notable interaction between the individual components. CdS-Sm-BDC-g-C3N4-5 wt% modified electrode exhibited higher peak current than the bare GCE, with excellent electrocatalytic ability to oxidize malathion, due to its higher conductivity, catalytic effect and synergistic effects between CdS, g-C3N4 and Sm-BDC. Under optimized condition, differential pulse voltammograms (DPV) demonstrate that the oxidation peak current was proportional to its concentration in the range of 3.0·10−8–15.0·10−8 M (R2 = 0.996), with high sensitivity (25 μAμM−1) and low detection limit (7.4·10−9 M or 7.4 μmM). In addition, the modified electrode affirms good stability and reproducibility, making it simple, cost effective with high sensitivity and selectivity. The results confirmed that making a composite is a key strategy for improving the physicochemical properties of MOFs and that modifying electrode surfaces with novel composites can enhance the detection of organophosphate pesticide.

The effect of expanded graphite and paraffin wax on the morphological, thermal, and rheological properties of PP/EVA blend

The study investigated the effect of paraffin wax, expanded graphite, and their dispersion on the properties of the blend of polypropylene (PP) and ethylene vinyl acetate (EVA). The idea is to reduce interfacial tension in blends of PP and EVA while enhancing the properties of blends in the process. The chosen optimum contents of the paraffin wax and EG in the 80/20 PP/EVA blend were 10 and 6 wt.%, respectively. The morphological features show that the expanded graphite (EG) particles had high affinity for each other. Moreover, EG filler particles are localized inside the minor EVA phase and some at the interface. Rheological properties revealed that the flow of the binary composites increased when 10 wt.% wax is added suggesting that wax enhanced the processability of the composites. The Cole-Cole plots deviated from the semi-circular arc suggesting heterogeneity in the blend and PP/EVA/Wax/EG composite. The addition of paraffin wax and EVA delayed crystallization of PP, while earlier crystallization of PP was promoted by the presence of EG. Generally, all samples caught fire after 10 s, started dripping and are thus given a V-2 rating according to the Underwriters Laboratories test standard 94 results (UL-94).

Enhanced Z-scheme ZnS/NH2−MIL-125(Ti) photocatalysts with biomass-derived carbon quantum dots for CO2 reduction

The conversion of CO2 and H2O into hydrocarbon fuels using solar energy represents a promising approach to artificial photosynthesis. However, the rapid recombination of photogenerated carriers presents a significant obstacle to the development of this technology. In this study, we extracted carbon quantum dots (CQDs) from waste biomass sludge and utilized them as electron transfer mediators between ZnS and NH2−MIL-125(Ti) for CO2 photoreduction. Comparative analysis with single-phase and binary composites revealed that the ZnS/CQDs/NH2−MIL-125(Ti) composites exhibited heightened photocatalytic activity and improved photostability. Electrochemical and optical investigations further elucidated that the incorporation of CQDs enhanced the charge separation efficiency and visible light responsiveness of the composites. The yields of CH3OH and CH3CH2OH achieved were 501.57 µmol/g and 564.70 µmol/g, respectively, following 3 h of visible light irradiation. This study presents a novel reference for utilizing biomass to facilitate the conversion of CO2 and H2O into valuable chemicals.

Numerical study on the design of flax/bamboo fiber reinforced hybrid composites under bending load

Natural fiber-based composites are essential for the environment in this era of depletion of petroleum resources and for new green environmental rules, as they have limited detrimental behavior or response against the environment. In this paper, firstly, the suitability of replacing glass fiber with natural bamboo fiber in a flax/glass/epoxy hybrid composite under a fixed bending load is investigated using Finite Element Analysis (FEA) software ABAQUS with proper model validation. Finally, five different lay-up sequences of flax/bamboo/epoxy hybrid composite laminate for fixed volume fractions of flax and bamboo strips are investigated numerically to develop design strategies for binary hybrid composite. It is found that the bending stiffness and equivalent modulus of elasticity for model FB-1 are increased by 37.53 % and 37.52 % respectively compared to the base model while the energy absorption for model FB-3 is highest which is 105.89 % higher than the base model. Analysis of various lay-up sequences showed that flexural behavior can be improved by fabricating binary hybrid composites using the concept of a sandwich structure. It is shown that all highly stiff laminas should be placed on the outer sides of the composite to achieve the maximum bending stiffness whereas they should be placed at the center to attain the maximum energy absorption.

Optimizing photocatalytic oxidative desulfurization using novel BiOI/B4C heterojunction in the presence of air and visible-light irradiation through response surface methodology (RSM)

In this study, different BiOI/B4C binary composites were evaluated as novel heterojunctions for the first time in the photocatalytic oxidative desulfurization process, and good results were obtained under visible light for the removal of dibenzothiophene sulfur compound with air oxidizer. The composites with different mass ratios were synthesized by hydrothermal method. In addition, different analysis including XRD, FT-IR, FE-SEM, EDX-MAP, TEM, BET, UV–vis DRS, PL, EIS and Mott-Schottky were used to identify the structure, morphology and performance of the composites. Hydroxyl and superoxide active species performed the three steps of electron-hole processing in the best way while improving the oxidation process with Z-scheme heterojunction. Experiment design process was carried out with Design Expert software and optimizing the parameters was performed in order to find the best operating conditions. The results showed that the optimal composite achieved the highest degradation performance of dibenzothiophene with a value of 95.1% in 30 min. In order to determine the degradation mechanism, trapping test was performed, and it was found that •O2– and •OH– radicals played a significant role in the photocatalytic process. In addition, due to the proper recovery of the BiOI/B4C heterojunction, this binary composite was proposed for industrial use.

Achieving superior pyroresistive reproducibility at HDPE/PVDF composites with tailored conductive phase size

AbstractCommercial conductive polymer composites (CPCs) with positive temperature coefficient (PTC) behavior usually suffer from inherent poor reproducibility of pyroresistive property. Herein, a conductive carbon black (CB)/high density polyethylene (HDPE)/polyvinylidene fluoride (PVDF) composite with outstanding PTC reproducibility were prepared through introducing cellulose nanocrystals (CNCs) grafted with methyl methacrylate (CNC‐g‐PMMA). Following the minimum interfacial energy mechanism, the CNC‐g‐PMMA tends to locate in PVDF of binary polymer composites. A much finer morphology of conductive CB/HDPE phase is hence obtained owing to the increasement of PVDF/HDPE viscosity ratio by introducing CNC‐g‐PMMA. Undergoing multiple repeated temperature cycles, the room temperature resistance and PTC intensity of as‐prepared material keep almost unchanged, which demonstrates superior PTC reproducibility. The improving mechanism of PTC reproducibility has also been illustrated in detail. This research provides a facile and valid strategy to enhance the PTC reproducibility and will vastly expand the application of PTC composites in the field of intelligent temperature management.Highlights Assembling binary polymer‐based PTC materials with cocontinuous structure Nanocrystals enables conductive HDPE phase with finer morphology. The precise ranges of viscosity ratio ensure the co‐continuous morphology. Small conductive phase size enhances P reproducibility. Narrow spatial domain restricts the self‐aggregation of conductive fillers.

Empowering Adsorption and Photocatalytic Degradation of Ciprofloxacin on BiOI Composites: A Material-by-Design Investigation.

Binary and ternary composites of BiOI with NH2-MIL-101(Fe) and a functionalized biochar were synthesized through an in situ approach, aimed at spurring the activity of the semiconductor as a photocatalyst for the removal of ciprofloxacin (CIP) from water. Experimental outcomes showed a drastic enhancement of the adsorption and the equilibrium (which increased from 39.31 mg g-1 of bare BiOI to 76.39 mg g-1 of the best ternary composite in 2 h time), while the kinetics of the process was not significantly changed. The photocatalytic performance was also significantly enhanced, and the complete removal of 10 ppm of CIP in 3 h reaction time was recorded under simulated solar light irradiation for the best catalyst of the investigated batch. Catalytic reactions supported by different materials obeyed different reaction orders, indicating the existence of different mechanisms. The use of scavengers for superoxide anion radicals, holes, and hydroxyl radicals showed that although all these species are involved in CIP photodegradation, the latter play the most crucial role, as also confirmed by carrying out the reaction at increasing pH conditions. A clear correlation between the reduction of BiOI crystallite sizes in the composites, as compared to the bare material, and the material performance as both adsorbers and photocatalyst was identified.

Preparation and properties of novel binary and ternary highly amorphous poly(vinyl alcohol)-based composites with hybrid nanofillers

Smart protective coatings and devices are currently of great interest. In particular, they can absorb or reflect harmful waves of electromagnetic interference (EMI). In this work, novel binary and ternary composites with highly amorphous poly(vinyl alcohol) (HAVOH) as a matrix and single-walled carbon nanotubes (SWCNTs) and MXenes as nanofillers were prepared. HAVOH is a recently patented kind of poly(vinyl alcohol) (PVOH) that was modified with diol monomers. MXenes are a new type of inorganic two-dimensional (2D) nanoparticle consisting of carbides, nitrides and carbonitrides. Three series of composites, HAVOH/SWCNTs, HAVOH/MXenes and HAVOH/SWCNTs/MXenes, were prepared using the solvent casting method. Samples were tested with various methods to study their structure, electrical properties, thermal behavior and EMI-shielding properties. HAVOH/3.0 wt.% SWCNTs/3.0 wt.% MXene specimens revealed a shielding effectiveness of 55 dB, which is 122 times better than that of the neat matrix. These results are promising for the fabrication of films with protective effects against EMI.

Improved photocatalytic degradation of rhodamine B by g-C3N4 loaded BiVO4 nanocomposites

Photocatalytic degradation has emerged as one of the most efficient methods to eliminate toxic dyes from wastewater. In this context, graphitic nitride (g-C3N4) loaded BiVO4 nanocomposites (5 wt% g-CN@BiVO4 and 10 wt% g-CN@BiVO4) have been fabricated by the wet impregnation method, and their efficiency towards photocatalytic removal of rhodamine B have been investigated under visible light irradiation. These hybrid composites have been characterized by XRD, FESEM, HRTEM, EDS-mapping, UV-Vis DRS, DLS, XPS and BET, etc. The HRTEM images revealed that BiVO4 has a decagonal shape covered by a layered nanosheet-like structure of g-C3N4. BET measurements suggest increasing the proportion of g-C3N4 results enhancement of the specific surface area. Among different photocatalysts, the 10 wt% g-C3N4@BiVO4 hybrid possesses the best catalytic activity with 86% degradation efficiency after 60 min of reaction time. The LC-MS studies suggest that the degradation reactions follow the de-ethylation pathway. Even after five cycles, the heterostructure shows only a 14% decrease in photocatalytic activity, confirming its stability. As a result, the binary composite can be regarded as a promising catalyst for the degradation of pollutants due to its ease of preparation, high stability and superior catalytic activity.

Thermal conductivity of binary ceramic composites made of insulating and conducting materials comprising full composition range – Applied to yttria partially stabilized zirconia and molybdenum disilicide

Thermal conductivity of binary ceramic composites made of insulating and conducting materials comprising full composition range – Applied to yttria partially stabilized zirconia and molybdenum disilicide

Synergistic improvement in electrochemical performance of Cr-doped MoS2/CuCo2S4 binary composite for hybrid supercapacitors

The synergistic effect of transition metal doping and composite formation can be imperative to improve the limited conductivity and inferior cyclic stability of MoS2 for supercapacitors. In this work, firstly, the impact of Cr-doping on the electrochemical activity of MoS2 has been discussed. Afterwards, the optimized Cr-doped MoS2 (CrMS-5) sample has been combined with CuCo2S4 (CCS) to further enhance its charge storage ability and cyclic stability. The CrMS-5/CCS composite delivers tremendous electrochemical activity as an electrode with a specific capacity of approximately 1324.08 C g−1 at 4 A g−1. The outstanding performance of the doped binary composite is on account of the synergism between doping and composite formation that results in increased conductivity and numerous redox active sites for charge storage. Furthermore, a symmetric supercapacitor device (SSC) has been fabricated using a CrMS-5/CCS electrode. It attains a high energy density of 46.63 Wh kg−1 corresponding to 1 kW kg−1 of power and exhibits remarkable cyclic stability of 81% for up to 5,000 cycles. The device illuminates a star-shaped LED panel of 12 red LEDs for 30 min. Thus, the above outcomes demonstrate the superiority of the doped MoS2-based composites for high-energy symmetric supercapacitors.

Interfacial modulation of α-Ag1.82Cu0.09WO4 with high active BiOClxI1−x for boosting photocatalytic activity and degradation of emerging contaminants under direct sunlight

Removal of organic contaminants in wastewater using sunlight-driven photocatalysts has received significant attention in recent years. However, the rational design of photocatalysts to attain high light absorption, lower charge carrier recombination with efficient photocatalytic activity and good recycling capability is crucial for the practical photocatalysis process. Herein, solid-state Z-scheme BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 heterojunction is synthesized by assembling hierarchical 3D-BiOCl0.6I0.4 nanoflowers on cube-like 3D-α-Ag1.82Cu0.09WO4 surface through a hydrothermal method. A wide range of characterization techniques confirms the successful synthesis of BiOClxI1−x (0 ≤ x ≤ 1.0), α-Ag1.82Cu0.09WO4 and BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composites. The TC antibiotic removal efficiency of 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composite reaches 95.91% within 120 min under natural sunlight irradiation and the rate constant is 1.81 and 3.33 times higher than the pristine BiOCl0.6I0.4 and α-Ag1.82Cu0.09WO4, respectively. The optimized binary heterojunction exhibits excellent photocatalytic performance for toxic pollutants like MB (η = 97.27%) and RhB (η = 95.75%) under direct sunlight irradiation. The favorable photocatalytic activity of binary heterojunction is ascribed to enhancing the sunlight absorption range, the tight contact interface and the effective separation of electron/hole pairs. Notably, 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composite exhibits attractive recycling ability and good photostability for prolonged sunlight irradiation. Furthermore, the total organic carbon results also confirm that the 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 efficiently mineralized the model pollutants (TC antibiotic, MB and RhB) into other unharmful compounds under sunlight irradiation. In summary, this work offers an effective strategy to prepare solid-state Z-scheme heterojunction with favorable photocatalytic activity, which can increase wastewater purification efficiency.

Immobilization performance of graphene oxide-based engineered biochar derived from peanut shell towards cationic and anionic dyes

Water pollution due to variety of organic contaminants is a serious global threat due to its adverse effects on aquatic life, terrestrial organisms and environment. In this sense, sustainable wastewater treatment using materials derived from lignocellulosic wastes has received considerable scientific attention because they are abundant, low-cost and functional-group rich. In this work, a facile approach has been demonstrated to design peanut shell biochar-graphene oxide (PBC@GO)-based binary composite. Herein, PBC@GO composite was fabricated and assessed as an adsorptive platform for cationic and anionic dyes viz. Crystal Violet (CV) and Bromophenol Blue (BPB), respectively, as model pollutants. The test materials were characterized by means of SEM, FTIR, XRD and TGA. The influence of pH, time, dosage and concentration of model pollutants was ascertained for optimal performance in batch mode. Results showed that PBC@GO efficiently removed CV (97 %) and BPB (87 %), whilst kinetic data accorded well with pseudo-second-order model with R2 values of 0.97 and 0.99 for CV and BPB, respectively. Moreover, equilibrium data was fitted to the Langmuir and Freundlich models to understand sorption mechanism for CV and BPB dyes. Comparative study showed synergistic effects of PBC and GO in terms of better removal efficiency due to the availability of multi-interaction sites in PBC@GO composite as compared to the precursors. Apart from superior pollutant's uptake ability, high % recoveries obtained by using spiked real water samples as well as long term stability of the prepared composite when subjected to five successive cycle of use without any substantial loss of its ability towards scavenging dyes were crucial for improving sustainability of water treatment systems.

Engineering 2D heterostructured VS2-rGO-Ni nanointerface to stimulate electrocatalytic water splitting and supercapacitor applications

The electrochemical oxygen evolution reaction (OER) is a key anodic response that turns renewable energy into fuels. Overcoming the obstacles (sluggish kinetics) in OER requires the development of a highly active electrocatalyst with excellent stability. For the first time, this study presents a new kind of nanostructured morphology of VS2-rGO-Ni ternary system for alkaline OER. A systematic investigation was carried out to optimize the excellent electrocatalyst using different arrays in the binary and ternary composites. The homogeneous and well-interconnected network structure is identified between the VS2 nanosheets (∼20 nm thickness) and rGO layered structure, including the dispersion of Ni nanoparticles. The OER performances of VS2-rGO-Ni-3 (rVN-3) in 1 M KOH were excellently stimulated, where the overpotential was lowered to 192 mV at 10 mA cm−2. After 2500 CV cycles and chronopotentiometry tests (10 mA cm−2), the electrocatalyst showed long-term stability without losing much activity. Although, the electrocatalysts were assembled in rVN-3||rVN-3 required cell voltage of 1.70 V which is able to achieve the threshold current density. The interfacial interaction between the VS2, rGO and Ni in the ternary composite leads to synergistic effect that significantly promotes the adsorption of oxygenated intermediates for an excellent OER process. Moreover, rVN-3 provided a reasonable supercapacitor performances, which confirms the multi characteristics properties. The nanostructured morphology with a well-connected network structure provides a large active surface for interacting with charge species and stable performance.

CuInS2/Poly(triarylamine) (PTAA) binary composite as an efficient hole transporter for carbon electrode-based perovskite solar cells

Perovskite solar cells (PSCs) with doped 2,2′,7,7′-Tetrakis[N,N-di(4- methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD) hole transport layer HTL suffers from instability due to dopants' hygroscopic nature. To ensure stability, inorganic materials are used as replacements, but still suffer from several drawbacks that can compromise their HTL role. Herein, we introduce organic Poly(triarylamine) (PTAA) into CuInS2 inorganic HTL to form a binary composite that suppresses these drawbacks. Results show a better hole extraction and favorable energy level alignment in binary-based devices concerning CuInS2-only devices, resulting in improved power conversion efficiency (PCE) from 14.68 to 16% after aging. Stability tests indicate binary HTL-based devices' superior stability retaining their complete initial PCE after 1720 h in a dark inert medium (∼15% humidity), and 70% after 408 h in a thermally stressed ambient medium (60 °C-40% humidity). Experimentally, the results indicate superior performance of binary HTL-based devices due to better film morphology, passivated defects and trap, and superior charge extraction.

Thermal conductivity improvement in silicon nitride ceramics via grain purification

Abstractβ‐silicon nitride (β‐Si3N4) ceramics with an additive oxide system of 1 wt% MgO and 3 wt% Re2O3 (Re = Gd, La, Y, and Yb) were fabricated by liquid phase sintering at 1950°C under nitrogen pressure of 748 kPa. Starting α‐Si3N4 powder with 10 vol% rod‐like β‐Si3N4 seed crystallites and an extended sintering time from 5 to 40 h resulted in the formation of bimodal microstructure composed of fine matrix grains and large grains. The 40 h‐sintered specimens of pseudo ternary β‐Si3N4‐MgO‐Gd2O3 system exhibited enhanced thermal conductivity of 127.2 ± 2.5 W m−1 K−1 associated with a degradation of the fracture strength from 1008.0 ± 38.0 to 491.7 ± 32.0 MPa, which was due to the formation of coarse‐grained aggregates that acted as both fracture origin as well as a thermal conductive pathway. The theoretical thermal conductivity was predicted for the sintered specimens by using equations based on a mean‐field micromechanics model to estimate the effective thermal conductivity of each component of binary composites. The calculation results suggested that the thermal conductivity of the large β‐Si3N4 grains (≥ 2 μm in diameter) was relatively high and estimated to be in the range of 175 to 191 Wm−1 K−1. The improved thermal conductivity of the 40 h‐sintered specimens was further discussed for the series of β‐Si3N4‐MgO‐Re2O3 systems based on the nanostructure characterization results obtained by the high‐resolution transmission electron microscopy and scanning transmission electron microscopy‐energy dispersive X‐ray spectrometry analyses.