Oxide Composites Research Articles

Sodium-Metal Battery Based on Reversible Oxide Chemistry at the Cathode

Sodium-metal batteries are considered as a promising energy storage alternative for currently available lithium-based batteries owing to their high gravimetric energy density and more specifically the natural abundance and the low price of Na metal that can lead to an inexpensive and low weight battery technology.In this study, we employ a Na-metal cell design that works based on reversible phase/composition change of sodium oxides (superoxide and peroxide) using a highly active cathode catalyst and an ether-based ionic-liquid electrolyte. The process involves in-situ production of sodium oxides in the controlled oxygen environment at the cathode. Subsequently, the cathode composed of sodium oxide compositions is assembled into a Na-metal architecture to do performance study and analysis. Our results indicated that the designed Na-metal battery demonstrates stable performance over 50 cycles with an overpotential of less than 100 mV and a coulombic efficiency exceeding 99%. Various electrochemical and physicochemical characterization techniques, including Raman spectroscopy, X-Ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission Electron Microscopy (TEM), were employed to gain insight into cell chemistry and mixed ion-electron conduction mechanism. The findings underscore the significance of well-designed cell components in Na-O2 battery technologies, positioning them as a promising avenue in energy conversion and storage systems.

Electrochemical-based amine functionalized gold nanoparticles decorated on nanosheets for normetanephrine detection in plasma and serum

Metals and metal oxide composites are prominent materials for detecting biomolecules in body fluids through electrochemical methods. In this study, iron-cobalt nanosheets (FeCoNS) decorated with glucosamine-functionalized gold nanoparticles (Gln-AuNPs) were synthesized to detect normetanephrine (NMN) in human plasma and serum samples. The morphology and chemical composition of the Gln-AuNPs@FeCoNS were analyzed via high-resolution transmission electron microscopy, field-emission scanning electron microscopy, atomic force microscopy, ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. A glassy carbon electrode (GCE) was modified with Gln-AuNPs@FeCoNS, exhibiting high electrochemical activity for determining NMN in phosphate buffer saline (PBS) and in real samples. Importantly, the increase in the oxidation current during the reaction between the GCE modified with Gln-AuNPs@FeCoNS and NMN enabled the detection and quantification of NMN. Cyclic voltammetry, differential pulse voltammetry, and amperometry (i-t) were used to assess the sensing performance of the GCE modified with Gln-AuNPs@FeCoNS. The fabricated sensor was highly sensitive toward NMN, with a limit of detection of 0.066, 0.085, and 0.7 µM in PBS, plasma, and serum samples, respectively. The proposed electrochemical sensor provides a new platform for utilizing active metal-based catalysts to detect various biomolecules.

Manufacturing of Fe-Ni Composite Oxide Powder and Leaching Process Optimization Via Nickel Pig Iron(NPI) Raw Materials

The lithium-ion battery industry is experiencing rapid growth in response to the widespread adoption of electric vehicles, leading to a significant increase in demand for high-purity nickel compounds, a critical raw material. As a result, ensuring a smooth supply of nickel resources poses a critical challenge not only for the battery industry but also for enhancing the competitiveness of future clean energy industries. High-purity nickel production is predominantly carried out via the high-pressure acid leach (HPAL) process, which extracts nickel from nickel laterite ores. However, this process involves substantial initial capital investment and consumes significant energy due to high temperatures, high pressure, and strong acids. Additionally, this method is associated with environmental concerns such as water and soil pollution. Furthermore, an alternative approach is proposed, which involves adding sulfur to low-grade nickel pig iron (NPI) to produce the nickel matte, followed by an iron removal process to generate high-purity nickel sulfide. However, this method presents challenges such as waste generation from the iron removal process, high carbon emissions, and the production of large amounts of greenhouse gases. This study explored using anodic oxidation to induce oxidative reactions in NPI to nano-powder. This approach improves nickel recovery efficiency by increasing the surface area compared to the bulk state, allowing leaching at room temperature and atmospheric pressure. As a result, the process becomes simpler, with lower initial capital investment, making it economically viable. Additionally, the process requires less energy consumption, allowing for achieving the breakeven point at an earlier stage. This study compared the characteristics of the nano-powderized NPI under different voltage and current ranges. Furthermore, the nickel leaching efficiency was assessed based on leaching solution conditions.

Removal of anionic dye from textile effluent using zirconium phosphate loaded polyaniline-graphene oxide composite: Lab to pilot scale evaluation

Efficient filtering of dyes is essential for the protection of ecosystem and human health due to the considerable water pollution caused by the effluents released from the sector. We present a simple, scalable UV radiation-assisted method for treating methyl orange dye-polluted water from the textile industry using zirconium phosphate-loaded polyaniline-graphene oxide (PGZrP) composite. The new material was synthesized by sonochemically incorporating a polyaniline-graphene oxide composite with hydrothermally synthesized zirconium phosphate. The efficacy of PGZrP in eliminating methyl orange was evaluated using experimental conditions, and the adsorption capacity was investigated as a function of pH, temperature, adsorbent dosage, and adsorption period. The system follows Langmuir adsorption isotherm with pseudo-second-order kinetics. Thermodynamics studies showed that enthalpy (H°) and entropy (S°) values are positive, indicating that the dye adsorption increases with increasing temperature and is an endothermic reaction. The maximum adsorption capacity was found to be 36.45379 mg/g for methyl orange. Using the COMSOL Multiphysics CFD Platform, an attempt was made to check the temperature and concentration profile of a PGZrP composite in a real industrial system. The predicted result shows that there is no significant temperature change in the material during the adsorption process and the concentration of dye is mainly located on the top region of the bed. The developed zirconium phosphate decorated polyaniline-graphene oxide composite can be successfully utilized for the effective removal of methyl orange from industrial wastewater in bulk quantity which is coming from the textile industry, and the composite can be reused for several cycles with good efficiency. In this work, we have designed a miniaturized proof of concept to remove methyl orange from water which showed good dye removal efficiency.

Modification and Reduced Graphene Oxide (rGO) Composites Based on MoS2: Improvement of Electrocatalytic Hydrogen Evolution Performance

Modification and Reduced Graphene Oxide (rGO) Composites Based on MoS2: Improvement of Electrocatalytic Hydrogen Evolution Performance

Research on Lithium Storage Performance of MoS2/rGO Composites

AbstractMoS2/reduced graphene oxide (MoS2‐I, MoS2/rGO‐II and MoS2/rGO‐V) composites with the mass ratio of MoS2 to GO is 1:1, 2:1 and 5:1, which were used as anode materials for lithium‐ion batteries (LIBs). The electrochemical properties and structure were tested and characterized. In the first cycle charge and discharge, the initial discharge capacity of MoS2/rGO‐II electrode is 821.8 mAh g−1 at 0.1 C, and the first coulomb efficiency is 92.09 %. The capacity attenuation of the second and third cycles is 65 mAh g−1 and 10.1 mAh g−1, respectively. Compared to MoS2 electrode, the attenuation of MoS2/rGO‐II electrode is obviously improved at different rates of 0.1 C, 0.2 C and 0.5 C, so MoS2/rGO‐II electrode shows excellent rate performance. Through the reaction mechanism analysis, it is concluded that most of the oxygen‐containing functional groups on the surface of GO are removed, but the conjugated network of graphene is not fully restored, resulting in the loss of electrical conductivity. However, the results of EIS directly show that rGO can still provide good conductivity for MoS2. Therefore, MoS2/rGO composites have great potential as electrodes for LIBs and broad research and application prospects in the field of energy storage.

Supercapacitor properties of partially oxidised-MXene quantum dots/graphene hybrids: Fabrication of flexible/wearable micro-supercapacitor devices

Recently, combining the synergistic properties of two-dimensional (2D) and zero-dimensional (0D) materials has attracted significant attention for energy applications. Here, we report the synthesis and characterization of partially oxidised-MXene quantum dots (PO-MXQDs) and reduced graphene oxide composite (PO-MXQDs/rGO) and investigate the resulting composites for energy storage applications towards supercapacitors. Density functional theory (DFT) simulations are used to examine the electrical and structural features of PO-MXQDs/rGO by predicting the chemical interaction involving charge transfer from PO-MXQDs to rGO. The multilayer Artificial Neural Network (ANN) model with hyperparameter tuning was developed at different input parameters to optimize material compositions, concentrations, and types of electrolytes to obtain the suitable conditions for best supercapacitive performance. The optimized PO-MXQDs/rGO showed a specific capacitance value of 1137.8 F.g−1 and was utilized for the fabrication of flexible micro-supercapacitors (FMSCs) device through the mask-assisted vacuum filtration process and asymmetric coin-cell type supercapacitor devices (ACCDs). The FMSCs deliver a higher areal capacitance (5.26 mF.cm−2), high areal energy density (0.46 μWh.cm−2), high areal power density (210.48 μW.cm−2), and the FMSC device has ultra-high cyclic stability up to 30000 cyclic voltammetry (CV) cycles. This method provides an in-depth study on developing 0D-2D hybrid materials with the wisdom of machine learning (ML) and DFT toward energy storage applications.

Design and Construction of Carbon-Coated Bimetallic Selenide Heterostructures Loaded on Reduced Graphene Oxide Substrate for Superior Lithium-Ion Storage.

In this work, carbon-coated bimetallic tin-nickel selenide heterostructures loaded on reduced graphene oxide composites were prepared through a metal-organic framework-assisted strategy. The carbon coating mitigates the volume expansion and maintains the structural stability, while the introduction of reduced graphene oxide and heterojunction enhances electrical conductivity and reaction kinetics, thereby together contributing to the enhanced lithium-ion storage performance. As expected, the optimal material delivers excellent lithium-ion storage performance in terms of a high reversible capacity of 1033.4 mAh g-1 at 0.2 A g-1, outstanding rate capability, and long-term cyclability with the capacity of 726.2 mAh g-1 after 500 cycles at 1.0 A g-1 and 452.4 mAh g-1 after 1000 cycles at 2.0 A g-1. Furthermore, the electrochemical reaction mechanism of the composite is analyzed.

Manufacture of flexible humidity sensors with high sensitivity and fast response using MoS2/graphene oxide composite

Manufacture of flexible humidity sensors with high sensitivity and fast response using MoS2/graphene oxide composite

The influence of Nano-composite metal oxides on the thermal decomposition performance of RDX

Abstract In order to investigate the effect of nano-composite metal oxides on the thermal decomposition performance of hexogen (RDX), this study prepared nano nickel-iron (NFO), nickel-cobalt (NCO), and nickel-iron-cobalt (NFCO) composite oxides by liquid-phase co-precipitation method. The precursor of Prussian blue analogs was synthesized and then calcined in air at 600°C. The addition of nano nickel-iron (NFO), nickel-cobalt (NCO), and nickel-iron-cobalt (NFCO) composite oxides to RDX has a significant impact on its thermal decomposition process. The peak exothermic temperatures were delayed by 8.4°C, 8.5°C, and 8.3°C, respectively, after adding the nano-composite metal oxides, and the heat release also increased to a certain extent. Among them, the addition of NCO nano-composite metal oxides had the greatest impact on the exothermic peak temperature of RDX, while the addition of NFCO nano-composite metal oxides resulted in the largest increase in heat release. This indicates that the addition of NFO, NCO, and NFCO to RDX altered the thermal decomposition reaction process to some extent.

Development of MWCNT/Gd2O3/SnO2 composite fabricated GCE for voltammetric detection of L- cysteine

A highly sensitive electrochemical method for the determination of L- Cysteine (L-cys) was developed using a glassy carbon electrode (GCE) modified with the composite of bimetallic gadolinium oxide (Gd2O3) and stannous oxide (SnO2) embedded on multi-walled carbon nanotubes (MWCNT). This modified electrode shows excellent electrocatalytic activity toward the oxidation of L-cys in a phosphate buffer solution (0.1 M, pH 7). The proposed electrode showed a linear range of 0.011 μM–27.7 μM, sensitivity of 0.048 μA μM−1 cm−2 and a detection limit (LOD) of 5.993 nM. X-Ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy-Dispersive X-ray Analysis (EDAX) was performed to characterize all the synthesized materials and the composite prior to electrode fabrication. Linear sweep voltammetry (LSV) was performed to account for the rise in the anodic peak in the potential concluding the current conductivity. Differential pulse voltammetry (DPV) was also performed to confirm the results. This work introduces a simple and easy approach to the sensitive detection of L-cys. Electrochemical impedance spectroscopy (EIS) and Cyclic voltammetry (CV) was employed to characterize the fabricated electrode and was used to investigate the redox properties of this modified electrode at various scan rates. This low-cost nanomaterial fabricated has a wide linear range with excellent stability and reproducibility. The practical applicability of the sensor was confirmed by sensing the L-cys in real samples, possessing satisfactory recoveries (95.8 % and 107.1 %).

Mitigating low-temperature hydrothermal degradation of 2 mol% yttria stabilised zirconia and of 3 mol% yttria stabilised zirconia/nickel oxide by calcium oxide co-doping and two-step sintering

Hydrothermal degradation deteriorates the fracture toughness and strength of tetragonal stabilised zirconia. The phase transformation to the monoclinic phase is particularly critical for materials with lower stabiliser content such as 2 mol% and 3 mol% yttria stabilised zirconia (2YSZ and 3YSZ). In this work, two routes in two-step sintering and co-doping with calcium oxide are analysed to mitigate the degradation. Both strategies show a reduction in average grain size of the 2YSZ while maintaining a comparable densification. The achieved smaller grains suppress the hydrothermal degradation rates. In addition, a mitigating effect beyond the reduction in grain size of YSZ is found for CaO doping. 1.6 mol% CaO co-doped 2YSZ shows less than 4% of monoclinic phase after 50 h in an autoclave with H2O at 134 °C. Pure 2YSZ contrarily reaches 100% monoclinic phase after 20 h at the same conditions. A suppression of degradation by CaO doping was also observed for the composite of nickel oxide and 3 mol% yttria stabilised zirconia. Hence, CaO co-doping can be an interesting strategy to increase resistivity against hydrothermal degradation for both biomedical and renewable energy applications. The findings further outline a route to achieve tetragonal YSZ with lower yttria contents than 2 mol%.

Exploring the photocatalytic degradation of methylene blue and carbol fuchsin dyes by magnesium codoped on graphene oxide and titanium dioxide green composites

Exploring the photocatalytic degradation of methylene blue and carbol fuchsin dyes by magnesium codoped on graphene oxide and titanium dioxide green composites

Molecular dynamics study of Gr(GO)/C-A-S-H composites at different temperatures: optimization of structural, dynamic and mechanical properties of civil engineering materials

In recent years, composites have been widely used in engineering fields, where nanomaterials such as graphene (Gr) and graphene oxide (GO) have potential advantages as interfacial modifiers in enhancing the properties of composites. However, the relationship between the interfacial structure and the mechanical properties of the nanocomposites is not clear, and the behavior of the composites may differ significantly at different temperatures. This study aims to investigate in depth the interfacial structure, dynamics, and mechanical properties of Gr, epoxy group-containing (-O) and hydroxyl group-containing (-OH) graphene oxide and calcium aluminosilicate hydrate (C-A-S-H) composites at different temperatures using molecular dynamics. The effect of nanomaterial composition on the interfacial chemical bonding network is revealed. The local chemical structures of bridging aluminum [Al(Q2b)] and interlayer aluminum (Alw) show different changes at different temperatures. Elevated temperature promotes the hydrolysis of interlayer water molecules to form hydroxyl groups, which affects the formation of chemical bonding networks.Al(Q2b) favors Gr and C-A-S-H linkages, whereas Alw favors GO and C-A-S-H bonding. Temperature changes lead to different chemical bonding connections and altered atomic motions. At the interface, Al atoms form a more stable chemical bonding network, which improves the interaction strength at the interface. Different composite models exhibited different mechanical properties at high temperatures and introducing epoxy and hydroxyl groups enhanced the plastic deformation of the composites. Structural analyses showed that temperature changes affected the molecular structure and interfacial bonding effects of the composites, which in turn affected the mechanical properties of the materials. At different temperatures, GO-O/C-A-S-H has higher tensile strength and Young's modulus, which can resist the degradation of performance caused by thermal expansion to a certain extent, and ensure the stability and safety of the structure, so it is more practical. These findings provide important insights to deepen the understanding of composite properties and have positive implications for future composite design and applications.

β-cyclodextrin-modified cobalt oxide as a heterogeneous catalyst for efficient peroxymonosulfate activation towards the degradation of Ciprofloxacin: Performance and degradation pathways

In this study, β-cyclodextrin-modified cobalt oxide (Co3O4@β-CD) composites were developed through hydrothermal processes and employed for heterogeneous activation of peroxymonosulfate (PMS) for the removal of ciprofloxacin (CIP) antibiotics. The results revealed that the degradation of CIP by Co3O4@β-CD/PMS was 99.13 %, which was significantly higher than the degradation of CIP by Co3O4/PMS (79.06 %) in a 25-minute period under optimal conditions ([Co3O4@β-CD] = 0.25 g/L, [PMS] = 0.25 mM, pH=7.0). The enhanced degradation of CIP contributed to the greater surface area (162.84 m2/g) of the Co3O4@β-CD to the Co3O4 (121.47 m2/g). Besides, the study assessed the impact of several reaction variables and interrupting anions on the abatement of CIP. A possible degradation procedure for CIP has been established by identifying reaction intermediates. The activation of PMS was achieved by both radical and non-radical routes. Further, Co3O4@β-CD exhibited remarkable stability and maintained its degrading efficiency after five consecutive cycles.

Bi2WO6 and TiS2 composite nanostructures displaying synergetic boosted energy storage in supercapacitor

The enhancement in the capacitance of a supercapacitor has been successfully achieved by synthesizing Bi2WO6 (BW), TiS2 (T), and Bi2WO6/TiS2 (BW/T) composites utilizing the hydrothermal process. The possible growth mechanism has also been presented. The morphological and structural characteristics of the cultivated samples were observed using FT-IR, XRD, SEM, EDS, and UV–vis spectroscopy techniques. TiS2 nano platelets uniformly dispersed across the hierarchically opened surface of Bi2WO6 in the synthesized hierarchical composite. This leads to an increase in surface porosity and surface area, which in turn enhances the transport of electrons and ions on the composite BW/T surface. The optimal electrode BW/T@40 % composite electrode shown a substantial enhancement in particular capacitance (1153.3 F/g) compared to the separate BW (523.7 F/g) and T (453.3 F/g) electrodes due to its rapid ion transfer, many active sites on its large surface area, and strong synergistic impact. Furthermore, the BW/T@40 % combination demonstrated exceptional stability, with over 92 % of its capacitance maintained after 4500th cycles and b value (0.71) proved the supercapacitor behavior. Therefore, BW/T@40 % binary metal oxide and sulfide composites exhibit improved specific capacitance and greatly prolonged life-cycle, confirming its potential use in high-performance energy storage devices.

Highly Stable MOFs-Derived Cu–Co Composite Metal Oxides for Catalytic Oxidation of Toluene

CuCoOx was prepared by in situ pyrolysis of Cu2+ partially substituted MOF-74 precursor with Co-MOF as a template for catalytic oxidation of toluene. T90 (the temperature corresponding conversion of 90%) was only 212°C, at 1000 ppm toluene and weight hourly space velocity (WHSV) of 36 000 mL g–1 h–1. In addition, the conversion was maintained above 97% for 74 h of continuous reaction at 260°C. Even if after 2400 ppm 1,2-dichloroethane (1,2-DCE) poisoning for 2 h, the toluene conversion was still up to 93%, demonstrating excellent stability and resistance to deactivation of catalyst. Furthermore, The high activity and stability of CuCoOx could be attributed to the large specific surface area as well as the high Co2+/Co3+, Cu2+/Cu+, and Olatt/Oads molar ratios.

Enhanced catalytic transfer hydrogenation of biomass-based furfural into furfuryl alcohol over Co3O4-based mixed oxide catalysts from hydrotalcite

Catalytic furfural (FF) into high value-added furfuryl alcohol (FOL) is a very important biomass improvement process and remains a challenging task. Herein, a series of Co-based composite oxide (CoMgAl-LDO) catalysts with highly dispersed Co3O4-based spinel oxide nanoparticles were synthesized by the topological transformation of Co-based ternary layered hydroxides (CoMgAl-LDH) under calcination conditions and tested for catalytic transfer hydrogenation of FF to FOL using isopropanol (2-PrOH) as hydrogen donor. The CoMgAl-LDO, especially Co1.5Mg1.5Al1-LDO calcinated at 500 °C (Co1.5Mg1.5Al1-LDO-500) offered the outstanding catalytic performance for the catalytic transfer hydrogenation of FF to FOL (99.7 % FF conversion and 95.9 % FOL selectivity), which was attributed to effectively dispersed active sites, abundant acid-base sites and mesoporous structure. Additionally, the Co1.5Mg1.5Al1-LDO-500 catalyst manifested good stability with wider universality to other carbonyl compounds, making the catalytic system extremely economical and practical in various biomass hydrogenation processes.

Corrosion resistance of FeCrMnxAlCu high-entropy alloys in 0.5M H2SO4 solution

In this study, FeCrMnxAlCu high-entropy alloys with varying Mn contents (x = 2.0, 1.5, 1.0, 0.5, and 0) were prepared using a vacuum arc melting furnace. The phase structure and microstructure of the alloys before and after corrosion were characterized via X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The corrosion resistance of the alloys in a 0.5 M H2SO4 solution was comprehensively evaluated through potentiodynamic polarization, electrochemical impedance spectroscopy, immersion tests, white light interferometry, and X-ray photoelectron spectroscopy. Microstructural characterization results revealed that the FeCrMnxAlCu high-entropy alloys exhibited mixed FCC and BCC phase structures and featured typical dendritic and interdendritic regions. Corrosion tests indicated that as the Mn content decreased, the corrosion resistance of the high-entropy alloys improved, and the corrosion type transitioned from dendritic to interdendritic. Among these alloys, the FeCrAlCu high-entropy alloy exhibited the highest corrosion resistance, with the highest positive corrosion potential (Ecorr = −0.11 V), the lowest corrosion current density (Icorr = 1.02 × 10−5 A∙cm2), minimal corrosion depth, and the lowest corrosion rate (0.1592 mm/y). After corrosion, a composite oxide protective film was formed on the alloy surface, effectively hindering further penetration of the H2SO4 solution and exhibiting excellent corrosion resistance.

Recent Advancements in the Development of Graphene‐Based Materials for Catalytic Applications

AbstractGraphene, a two‐dimensional material, presents unprecedented opportunities for catalytic applications, attributable to its unique planar structure, outstanding optical transmittance, superior electronic conductivity and mobility, extensive specific surface area, and elevated chemical stability, coupled with its tunability. In recent years, graphene‐based catalysts have garnered significant research attention and interest. This review aims to elucidate recent advancements in the synthesis of graphene‐based catalysts. It encompasses discussions on heteroatom‐doped metal‐free graphene catalysts, graphene composite catalysts (including graphene/metal and graphene/metal oxide composites), and their applications in various catalytic domains such as electrocatalysis, photocatalysis, and catalysis of organic reactions.