Manganese Zinc Research Articles

Biosynthesis and activity of Zn-MnO nanocomposite in vitro with molecular docking studies against multidrug resistance bacteria and inflammatory activators

This study investigated the green synthesis of Zn-MnO nanocomposites via the fungus Penicillium rubens. Herein, the synthesized Zn-MnO nanocomposites were confirmed by UV-spectrophotometry with a top peak (370 nm). Transmission electron microscopy confirmed irregular particles with a spherical-like shape ranging from 25.13 to 36.21 nm. Numerous functional groups were detected on the surface of Zn-MnO nanocomposite via Fourier-transform infrared spectroscopy. X-Ray diffraction assay appeared that the synthesized Zn-MnO nanocomposites contained two different components, MnO (JCPDS 81-2261) and ZnO (JCPDS 36-1451), while energy dispersive X-ray spectra confirmed the occurrence of manganese, zinc, oxygen, and carbon in Zn-MnO nanocomposites. Zn-MnO nanocomposites demonstrated excellent suppress effect versus the growth of various bacteria namely Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Salmonella typhi, and Klebsiella pneumoniae via agar well diffusion assays with inhibition areas of 36 ± 0.1, 25 ± 0.1, 27 ± 0.2, and 23 ± 0.2 mm, correspondingly. Alterations in the ultrastructure of the treated K. pneumoniae by Zn-MnO nanocomposite were recorded. Both the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration of Zn-MnO nanocomposite extended from 15.62 to 125 µg/mL employing the examined bacteria. The antibiofilm activity of Zn-MnO nanocomposites was 82.07, 75.43, 43.65, and 41.35% at 25% MIC, and 96.54, 93.0, 94.53, and 91.11% at 75% MIC against S. aureus, MRSA, K. pneumoniae, and S. typhi, respectively. At 25 to 75% MIC, Zn-MnO nanocomposites exhibited antihemolytic activity with the maximum activity of 96.3% at 75% MIC in the presence of MRSA. Extensive molecular docking studies were performed to identify the optimal location for manganese oxide and zinc oxide nanoclusters binding to MRSA. MnO-NPs and ZnO-NPs demonstrated inhibitory activity against the crystal structure of putative minohydrolase (PDB ID: 4EWT), methicillin acyl-penicillin binding protein 2a structure (PDB ID: 1MWU) and K2U bound crystal structure of class II peptide deformylase from MRSA (PDB ID: 6JFQ). The minimum binding energy was utilized to estimate the receptor’s binding site with NPs, providing additional understanding of the ways of action. Anti-inflammatory activity of Zn-MnO nanocomposites via cyclooxygenase-1 and cyclooxygenase-2 enzymes inhibition was documented with IC50 doses of 20.81 ± 0.68 µg/mL and 35.87 ± 1.35 µg/mL, respectively. Based on these outcomes, it was concluded that Zn-MnO nanocomposites could be useful agents for the management of multidrug resistant bacterial pathogens and inflammation.

Cation-regulated MnO2 reduction reaction enabling long-term stable zinc–manganese flow batteries with high energy density

Reversible Mn2+/MnO2 reaction for Zn–Mn flow batteries achieved by modulating the solvation-shell structure of Mn2+ and the structure of electrodeposited MnO2 through a cation-assisted effect.

Spatial Confinement Effect of Mineral‐Based Colloid Electrolyte Enables Stable Interface Reaction for Aqueous Zinc–Manganese Batteries

AbstractThe rational design of inorganic colloid electrolytes enables the manipulation of the solvation structure of Zn2+ ions and addresses zinc dendrite formation and manganese dissolution in aqueous zinc–manganese batteries. In this study, magnesium aluminosilicate (MAS) powder is used to fabricate a mineral‐based colloid electrolyte for Zn//α‐MnO2 batteries. According to theoretical calculations, MAS has a stronger binding energy with Zn2+/Mn2+ ions than with H2O molecules, suggesting the possibility of regulating the solvation structure of Zn2+/Mn2+ ions in a MAS–colloid electrolyte. Based on the experimental results, a high ionic conductivity, wide operating voltage, low activation energy barrier, and stable pH environment is achieved in the MAS–colloid electrolyte. As expected, long‐term cyclic stability can be maintained for 3500 h at 0.2 mA cm−2 in Zn//Zn cells, and high capacities of 255.5 and 239.8 mAh g−1 are retained at 0.2 and 0.5 A g−1 after 100 cycles in Zn//α‐MnO2 batteries, respectively. This performance is attributed to the spatial confinement effect of MAS on the active H2O molecules, which effectively reshapes the solvation structure of Zn2+ ions, guaranteeing reversible zinc deposition, suppressing active manganese dissolution, and ensuring stable interfacial reactions. This work will drive the development of mineral‐based electrolytes in zinc‐based batteries.

ZnMnCoS/rGO nanocomposite for an effective bifunctional electrode for overall water splitting and supercapacitor applications

Abstract Future energy storage and energy conversion devices will benefit from the development of active electrode materials that serve as both an electrocatalysts and an energy storage device. Recently, mixed metal sulfides are cheaper and have improved electrical and electrochemical performance than their oxide/hydroxide similarly has garnered a lot of interest for use in energy storage and electro catalysis applications. In this, mixed metal sulfides, as zinc manganese cobalt sulfide (ZMCS) and reduced graphene oxide composite zinc manganese cobalt sulfide (rZMCS) were successfully synthesized via hydrothermal route for overall water splitting and supercapacitor. The prepared materials are characterized through x-ray diffraction, x-ray photoelectron spectroscopy, Field emission scanning electron microscope, transmission electron microscope with elemental mapping and Brunauer–Emmett–Teller analysis. The ZMCS and rZMCS electrodes exhibit an over-potential of 258 and 170 mV for HER and 302 and 230 mV for OER at a density of current is 10 mA cm2 in 3 M KOH. Overall water splitting is carried out for rZMCS electrodes and it shows the long-term stability of 15 hrs. The specific capacitances of ZMCS and rZMCS electrodes are 1065 F g1 and 1167 F g1 at 1 A g1. The obtained electrode could maintain 96 % and 98 % until 5000 cycles. Asymmetric supercapacitor device rZMCS//rGO delivers a total amount of energy and power is 47.6 Wh kg1 and 925 W kg1 with could maintain 86 % upto 10000 cycles. The outcomes draw attention to the produced electrode able to be practical as a multifunctional electrode for energy storage and conversion devices.

Organic-inorganic hybrids: A comprehensive review on synthesis and their potential applications

Organic-inorganic hybrids highlight the advantages of the presence of organic compounds, due to their stability, flexibility, and adaptability, as well as the structural features of inorganic materials. This review delves into the interaction between conducting polymers (CPs) and metal oxides (MOs), showcasing their combined advantages in various sectors such as sensors, capacitors, catalysts, and fuel cells. This paper explores the synthesis methods of prominent CPs including Polypyrrole (PPy), Polyaniline (PANI), Poly(3,4-ethylene dioxythiophene) (PEDOT), and Polyindole (PIn), along with a spectrum of MOs like zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO2), manganese dioxide (MnO2), iron oxides (Fe2O3 and Fe3O4), and nickel oxide (NiO). Diverse preparation techniques such as chemical oxidative, emulsion, and interfacial polymerization for CPs have been reported. Hydrothermal, co-precipitation, and sol-gel methods have been studied to synthesize MOs. Advanced characterization techniques such as Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) have been reported to study the structural and morphological aspects of CP-MO hybrids. These hybrids exhibit potential applications in sensors, biosensors, antimicrobial activity, energy storage devices, and photocatalysis. This review provides a comprehensive overview, which aims to explore the prospects and innovations in the area of organic-inorganic hybrids.

Revealing Failure Mechanisms in Zinc-Manganese Dioxide Batteries Via Nondestructive Electrochemical Diagnostics

The world of long-term-high-density energy storage systems is dominated by the lithium-ion (Li-ion) battery. However, associated setbacks with the Li ion industry such as safety, geopolitical concerns, and rising costs have spearheaded research into investigating alternative approaches to the Li-ion batteries. A promising alternative to the Li-ion battery is the zinc manganese oxide (Zn||MnO2) battery due to its high energy density and much safer chemistry. However, a step towards commercialization of the Zn||MnO2 requires a deep dive into the failure mechanisms native to such cells. These failure mechanisms are identified as electrolyte degradation, increased cell impedance, loss of Zn inventory, and loss of cathode inventory.Conventionally, techniques employed in identifying failure mechanisms are destructive and time consuming. Thus, there is the need to investigate reliable nondestructive techniques which can predict failure mechanism in Zn|MnO2 cells. In this research an electrochemical approach is pursued, employing the use of cell features such as rest potentials and columbic efficiencies to model various failure mechanisms in Zn||EMD cells. Prior to investigating failure mechanisms, optimization of the Zn||EMD cell is explored based on particle size, EMD weight composition, and electrolyte volume to minimize Mn2+ dissolution.

Retraction Note: Biocompatibility and Antimicrobial Investigation of Agar-Tannic Acid Hydrogel Reinforced with Silk Fibroin and Zinc Manganese Oxide Magnetic Microparticles

Retraction Note: Biocompatibility and Antimicrobial Investigation of Agar-Tannic Acid Hydrogel Reinforced with Silk Fibroin and Zinc Manganese Oxide Magnetic Microparticles

Physical and electrochemical performance of Mn-doped zinc oxide electrode material for asymmetric supercapacitor

Manganese-doped zinc oxide has emerged as a promising material for high-performance supercapacitors (SCs) due to its enhanced electrochemical properties, including improved charge storage capacity and cycling stability. Pristine Zinc oxide (ZO) and Manganese (Mn) doped (2 wt % and 4 wt %) zinc oxide (hereby labeled: ZO, 2MZO, and 4MZO) derivatives have been synthesized via an aqueous sol-gel-based co-precipitation method. The physical characterizations of synthesized samples have been performed using TGA, XRD, FESEM, and BET. The XRD has confirmed the phase pure hexagonal wurtzite structure synthesis of ZO, 2MZO, and 4MZO samples. The FE-SEM images revealed that synthesized material had shown the mixed morphology as polyhedral particles, rods, and flakes in the nano region. Mn-doped has increased specific surface by 132 % compared to bare ZO. The electrochemical characterization techniques, including CV, GCD, and EIS, have been used to access electrochemical parameters using an aqueous 4 M KOH electrolyte. A detailed CV analysis was also carried out to investigate the capacitive contribution of the material in cycling. The electrochemical characterization techniques (CV, GCD, and EIS) have been performed to access electrochemical parameters using an aqueous 4 M KOH electrolyte. The 4MZO electrode material has shown an enhancement in specific capacitance (164.28 Fg-1) compared to pristine ZO (42.83 Fg-1). The EIS study revealed that the 4MZO has the lowest internal impedance 0.30 Ω compared to 0.70 Ω, and 2.60 Ω for 2MZO and ZO, respectively.

Spent coffee to carbon: blending with manganese zinc ferrite as a plasmonic photocatalysis for degradation of organic dyes

ABSTRACT In this work, we introduce a new composite material consisting of Mn(1-x)ZnxFe2O4 (MZF) and wasted coffee grounds carbon (C). Crucially, the surface chemistry of the ‎composite, which lacks Zn2+ ions in octahedral locations, highlights its distinctive structural ‎characteristics. Before the integration of the carbon composite, the saturation magnetisation ‎of the sample was recorded as 53.073 emu/g. However, it decreased to 45.49 emu/g ‎after the composite was formed and the reaction processes occurred. UV-spectroscopy ‎enabled the measurement of band gap energies, which showed that the band gap energies for ‎ferrite were 2.93 eV and for the MZF/C composite were 2.12 eV. By utilising plasmonic ‎photocatalysis, the MZF/C composite has shown exceptional effectiveness as a high-temperature photocatalyst, specifically in the breakdown of methylene blue (MB) and Eosin (EO) dyes, ‎which are representative of basic and acidic dyes, respectively. The study demonstrated enhanced photocatalytic degradation kinetics under both visible light and sunlight, with sunlight showing superior performance. Over a 120-min period, the ferrite composite achieved a removal efficiency of 89% under sunlight, compared to 68% under artificial light. By utilising plasmonic photocatalysis principles, this work clarifies the structural and optical ‎properties of the MZF/C composite and emphasises its capacity to tackle environmental ‎issues through effective dye degradation mechanisms.‎

Growth and spectra studies of nonlinear optical manganese zinc hydrogen phosphate (MnZnHPO4) single crystals

Growth and spectra studies of nonlinear optical manganese zinc hydrogen phosphate (MnZnHPO4) single crystals

Correction: Growth and spectra studies of nonlinear optical manganese zinc hydrogen phosphate (MnZnHPO4) single crystals

Correction: Growth and spectra studies of nonlinear optical manganese zinc hydrogen phosphate (MnZnHPO4) single crystals

In-situ synthesis of synergistic ZnMn2O4/MnOOH nanocomposite as a cutting-edge pseudocapacitive electrode material for all-solid-state asymmetric supercapacitors

Currently, there has been a growing interest in constructing metal oxide composite structures through the in-situ synthesis method, especially for fabricating electrode materials for supercapacitors. This approach offers several advantages, such as improved contact between different materials, enhanced conductivity, efficient ion diffusion, and better overall electrochemical performance. This work investigates the synthesis of zinc manganese oxide and manganese oxyhydroxide (ZnMn2O4/MnOOH) composite using a solvothermal method. The structure, surface morphology, and composition of the ZnMn2O4/MnOOH composite were elucidated using standard physicochemical characterization techniques where the presence of ZnMn2O4 and MnOOH phases was confirmed and the ZnMn2O4/MnOOH nanocomposite behaved as a pseudocapacitive electrode with a notable specific capacitance of 1039.2 F g⁻1 at a current density of 1 A g⁻1. When subjected to a 10-fold increase in current density, the ZnMn2O4/MnOOH electrode maintained 50 % of its initial capacity, registering 513.4 F g⁻1. Additionally, the electrode showcased excellent cyclic stability, preserving 95 % of its initial capacity after 5000 cycles at 10 A g⁻1. Moreover, the constructed ZnMn2O4/MnOOH//activated carbon (AC) asymmetric supercapacitor (ASC) device attained a high energy density of 29.45 Wh kg⁻1 at a power density of 1384.5 W kg⁻1. The results confirm that the ZnMn2O4/MnOOH composite, prepared in a single synthesis step, shows great potential as a phenomenal pseudocapacitive electrode for energy storage applications.

Investigation on corrosion behaviour of metal oxide nanoparticles reinforced magnesium composites by salt spray and immersion corrosion test methods

ABSTRACT This study explores the increasing utilisation of lightweight materials, particularly magnesium (Mg) alloy, in sectors such as automobile, aerospace, and marine due to its notable advantages such as high strength-to-weight ratio, good castability, and excellent damping capacity. Despite these merits, Mg alloy faces challenges, notably in wear and corrosion resistance. The research focuses on enhancing the corrosion resistance of Mg alloy by incorporating Zinc Oxide (ZnO), Manganese Oxide (MnO), and Titanium Oxide (TiO2) nanoparticles. The alloy AZ91D and three nanocomposites, namely AZ91D + 1% ZnO, AZ91D + 1% MnO, and AZ91D + 1% TiO2, were manufactured using a stir squeeze casting technique combined with an ultrasonication process. To confirm the even distribution of reinforcement particles, Optical Microscope (OM), Scanning Electron Microscope (SEM) and High-Resolution Scanning Electron Microscope (HR-SEM) were employed. X-ray Diffraction (XRD) analysis revealed the presence of matrix and reinforcement material with intermetallic precipitates around the grain boundaries. Corrosion properties were assessed following ASTM standards and utilising a 3.5% NaCl concentration. The study found that AZ91D + 1% TiO2 nanocomposites exhibited superior corrosion resistance compared to the AZ91D alloy, showing a remarkable 77.78% and 69.89% improvement in corrosion behaviour under salt spray and immersion environments, respectively, after 48 hours.

Photocatalytic degradation of rhodamine B using Yb3+-Doped Zn-Mg ferrites synthesized via conventional sol-gel auto-combustion method

The primary goal of our research is to develop a photocatalyst capable of degrading organic molecules in water, achieved through the rare earth Yb3+ doping of Zn-Mg spinel ferrites. A key element of our approach is the use of the conventional sol-gel auto-combustion process, which has proven to be an effective method for synthesizing a high-performing, visible light-driven Zn0.9Mg0.1Fe2-xYbxO4 (x = 0.000, 0.015, 0.030, 0.045, 0.060 and 0.075) nano-ferrites. Many analytical techniques were employed to evaluate the material's physicochemical characteristics, including P-XRD, EDX, FE-SEM, HR-TEM, FTIR, UV–vis, BET, VSM, EIS, and photocatalysis was carried out against the RhB. The impact of Yb3+ ion doping on the material's crystallite size and lattice parameter has been evaluated. It was found that all the samples' crystallite sizes increased between 33 and 41 nm. These magnetite nanoparticles have spherical forms and nanometric particle sizes, as revealed through field scanning electron microscopy (FE-SEM). The FTIR spectra bands at ʋ1 (518–535) and (401–411) ʋ2 subsequently revealed the spinel structure of the synthesized nano-ferrites. The band gap in zinc manganese ferrite increases from 2.51 eV to 2.92 eV after adding ytterbium. The surface area of the Yb3+-doped Zn-Mg ferries ranges from 23.6 m2/g to 27.8 m2/g, making them an excellent choice for data storage. The investigation of magnetic behavior shows the superparamagnetic behavior of all the samples. The produced sample's determined squareness value indicates the magnetostatic interaction between the particles. Because of the low produced coercive field value, these materials can be used in ferrofluids and hyperthermia therapy applications. Furthermore, with a higher RhB removal of 93.80 %, the Yb3+-doped sample photocatalyst successfully separated carriers generated by sunlight. The Yb3+-doped sample (ZMY-5) photocatalyst showed outstanding stability after one cycle of the stability test, obtaining an outstanding RhB elimination of 93.80 %. Zn0.9Mg0.1Yb0.075Fe1.925O4 photocatalyst has substantial promise for large-scale pollutant treatment due to its simple synthesis method, superior magnetic characteristics, exceptional photocatalytic activity for RhB, and excellent stability.

ZnMn2O4‐BiVO4 as Photocatalyst for Degradation of Gaseous HCHO Using Daylight

AbstractFormaldehyde (HCHO) is a common indoor air pollutant. Due to its proven carcinogenicity, reducing indoor HCHO levels is a significant issue. In this study, a composite material consisting of zinc manganese oxide and BiVO4 was used as a photocatalyst for HCHO degradation. ZnMn2O4‐BiVO4 has efficient photocatalytic performance, wide application areas, high stability, and low‐cost advantages, making the substance a potentially useful photocatalyst that can be applied in fields such as energy conversion and environmental protection. BiVO4 was prepared by a hydrothermal method. It was further compounded with zinc manganese oxide to form composite as catalysts of different wt % ratios for photodegradation of HCHO using a fluorescent lamp as light source. The samples were characterized by using XRD, UV‐visible spectrometer, TEM, SEM, and photoluminescence spectrometry. The experimental data showed that 5.0 wt % zinc manganese oxide‐BiVO4 as catalyst had the highest HCHO degradation rate. The release of carbon dioxide and water increased the irradiation time. The degradation rate of HCHO was higher than that achieved with commercially available titanium oxide. The highest HCHO degradation rate was 66 % within 4 h.

Seed-Assisted Reversible Dissolution/Deposition of MnO2 for Long-Cyclic and Green Aqueous Zinc-Ion Batteries.

Manganese oxide (MnO2) based aqueous zinc-ion batteries (AZIBs) are considered to be a promising battery for grid-scale energy storage. However, they usually suffer from the great challenge of capacity attenuation due to Mn dissolution and irreversible structural transformation. Herein, full use of the shortcomings is made to design high-performance cathode-free AZIBs. Manganese-based Prussian blue analog (Mn-PBA) is selected as a seed layer to provide a stable MnO2 electrodeposition surface. Thanks to the large specific surface area and manganophilic nature of Mn-PBA, the deposition/dissolution kinetics between Mn2+ and MnO2 are significantly enhanced. Systematic studies revealed the mechanism of MnO2 deposition-dissolution related to the reversible transformation of manganese oxide hydroxide and zinc hydroxide sulfate hydrate. Based on this, the developed cathode-free AZIBs exhibit outstanding rate performance (with a specific capacity of 273.7 mAh g-1 at 1 A g-1) and extraordinary cycle stability (maintaining a specific capacity of 52.3 mAh g-1 after 50000 cycles at 20 A g-1). Furthermore, the AZIBs with non-toxic, biocompatible materials can be directly discarded after use, without causing pollution to the environment, which is expected to help achieve the sustainable development goals.

Nutrient strengthening and lead alleviation in Brassica Napus L. by foliar ZnO and TiO2-NPs modulating antioxidant system, improving photosynthetic efficiency and reducing lead uptake

With the anticipated foliar application of nanoparticles (NPs) as a potential strategy to improve crop production and ameliorate heavy metal toxicity, it is crucial to evaluate the role of NPs in improving the nutrient content of plants under Lead (Pb) stress for achieving higher agriculture productivity to ensure food security. Herein, Brassica napus L. grown under Pb contaminated soil (300 mg/kg) was sprayed with different rates (0, 25, 50, and 100 mg/L) of TiO2 and ZnO-NPs. The plants were evaluated for growth attributes, photosynthetic pigments, leaf exchange attributes, oxidant and antioxidant enzyme activities. The results revealed that 100 mg/L NPs foliar application significantly augmented plant growth, photosynthetic pigments, and leaf gas exchange attributes. Furthermore, 100 mg/L TiO2 and ZnO-NPs application showed a maximum increase in SPAD values (79.1%, 68.9%). NPs foliar application (100 mg/L TiO2 and ZnO-NPs) also substantially reduced malondialdehyde (44.3%, 38.3%), hydrogen peroxide (59.9%, 53.1%), electrolyte leakage (74.8%, 68.3%), and increased peroxidase (93.8%, 89.1%), catalase (91.3%, 84.1%), superoxide dismutase (81.8%, 73.5%) and ascorbate peroxidase (78.5%, 73.7%) thereby reducing Pb accumulation. NPs foliar application (100 mg/L) significantly reduced root Pb (45.7%, 42.3%) and shoot Pb (84.1%, 76.7%) concentration in TiO2 and ZnO-NPs respectively, as compared to control. Importantly, macro and micronutrient analysis showed that foliar application 100 mg/L TiO2 and ZnO-NPs increased shoot zinc (58.4%, 78.7%) iron (79.3%, 89.9%), manganese (62.8%, 68.6%), magnesium (72.1%, 93.7%), calcium (58.2%, 69.9%) and potassium (81.5%, 68.6%) when compared to control without NPs. The same trend was observed for root nutrient concentration. In conclusion, we found that the TiO2 and ZnO-NPs have the greatest efficiency at 100 mg/L concentration to alleviate Pb induced toxicity on growth, photosynthesis, and nutrient content of Brassica napus L. NPs foliar application is a promising strategy to ensure sustainable agriculture and food safety under metal contamination.

Impact of activation energy and thermal radiation on hybrid nanofluid (engine oil + nickel zinc ferrite + manganese zinc ferrite) flow over a wavy cylinder in the presence of induced magnetic field

Impact of activation energy and thermal radiation on hybrid nanofluid (engine oil + nickel zinc ferrite + manganese zinc ferrite) flow over a wavy cylinder in the presence of induced magnetic field

Response surface methodology-based new model to optimize heat transfer and shear stress for ferrites/motor oil hybrid nanofluid

PurposeThis study aims to optimize heat transfer efficiency and minimize friction factor and entropy generation in hybrid nanofluid flows through porous media. By incorporating factors such as melting effect, buoyancy, viscous dissipation and no-slip velocity on a stretchable surface, the aim is to enhance overall performance. Additionally, sensitivity analysis using response surface methodology is used to evaluate the influence of key parameters on response functions.Design/methodology/approachAfter deriving suitable Lie-group transformations, the modeled equations are solved numerically using the “spectral local linearization method.” This approach is validated through rigorous numerical comparisons and error estimations, demonstrating strong alignment with prior studies.FindingsThe findings reveal that higher Darcy numbers and melting parameters are associated with decreased entropy (35.86% and 35.93%, respectively) and shear stress, increased heat transmission (16.4% and 30.41%, respectively) in hybrid nanofluids. Moreover, response surface methodology uses key factors, concerning the Nusselt number and shear stress as response variables in a quadratic model. Notably, the model exhibits exceptional accuracy with $R^2$ values of 99.99% for the Nusselt number and 100.00% for skin friction. Additionally, optimization results demonstrate a notable sensitivity to the key parameters.Research limitations/implicationsLubrication is a vital method to minimize friction and wear in the automobile sector, contributing significantly to energy efficiency, environmental conservation and carbon reduction. The incorporation of nickel and manganese zinc ferrites into SAE 20 W-40 motor oil lubricants, as defined by the Society of Automotive Engineers, significantly improves their performance, particularly in terms of tribological attributes.Originality/valueThis work stands out for its focus on applications such as hybrid electromagnetic fuel cells and nano-magnetic material processing. While these applications are gaining interest, there is still a research gap regarding the effects of melting on heat transfer in a NiZnFe_2O_4-MnZnFe_2O_4/20W40 motor oil hybrid nanofluid over a stretchable surface, necessitating a thorough investigation that includes both numerical simulations and statistical analysis.

Modulating the Structure of Interlayer/Layer Matrix on δ‐MnO2 via Cerium Doping‐Engineering toward High‐Performance Aqueous Zinc Ion Batteries

Abstractδ‐MnO2 has been vigorously developed as an ideal cathode material for rechargeable aqueous zinc‐ion batteries (AZIBs) due to its spacious layer spacing suitable for ion storage. However, poor intrinsic conductivity, structural collapse, and sluggish reaction kinetics are major limitations restricting their battery performance. Doping engineering has been proven to be an effective strategy for modifying the structure, conductivity, and electronic properties of Mn‐based oxides. Here, a series of δ‐MnO2 hierarchical flowers with different cerium‐doped sites are proposed as high‐performance cathodes for AZIBs, revealing the effects of various Ce doping sites on the MnO2 layer‐by‐layer structure and battery performance. Chemical analysis and theoretical calculations indicate that δ‐MnO2 with both in‐layer and interlayer Ce doping (Cein/inter‐MnO2) allows for sufficient Zn2+ storage sites, higher conductivity, and enhanced reaction kinetics due to enlarged interlayer spacing, increased oxygen defects, and reduced Coulombic repulsion between zinc ions and manganese oxide hosts. As a result, Cein/inter‐MnO2 with extended ion transfer channels and sturdy structure delivers a superior capacity of 348.8 mAh g−1 at a current density of 300 mA g−1 over 100 cycles, and a high retention rate of ≈100% at a current density of 3000 mA g−1 over 2000 cycles.