Manganese Oxide Research Articles

A Pleiotropic Nanomedicine Mitigates Splenic Hyperplasia, Ineffective Erythropoiesis, G6PDH Anomaly through Redox Buffering in Preclinical Mice Model.

Here, we present a pleiotropic nanomedicine-a smart, functionalized redox buffering nanoparticle-that may be used to treat hematological diseases, associated splenic hyperplasia, and issues related to restricted erythropoiesis. With a diameter of 5-7 nm, the spherical nanomaterial is made of manganese oxide and citrate. Here, we have produced the novel nanomaterial and, using cutting-edge electron microscopic and spectroscopic techniques, extensively assessed its redox buffering potential in vitrowith its structural integrity. Using an appropriate animal model (phenyl hydrazine, PHz, intoxicated C57BL/6J mice), we assessed the therapeutic efficacy of the redox buffering nanomedicine in the treatment of anemia and related consequences. We have further investigated the intricate molecular mechanism of the nanomedicine and its therapeutic impact, which includes increased erythropoiesis and G6PDH production, decreased inflammatory responses, mitigation of splenic hyperplasia, and synergistic intracellular redox-buffering. To the best of our knowledge, our studies would find relevance in the innovative management of anemia, decreased erythropoiesis, and splenic hyperplasia.

Oligopeptide template-guided nanoconfined in situ mineralization of nanotherapeutics boosts self-sufficient immunogenic phototherapy.

As a promising cancer treatment modality that has emerged, photodynamic / photothermal therapy can harness antitumor immunity by triggering immunogenic cell death in addition to direct cell ablation. However, the efficacy of this phototherapy is always limited due to the hypoxic tumor microenvironment, and the induccd immune stimulation is insufficient to achieve satisfactory cancer eradication. We herein address the above issues by nanoconfined in situ mineralization of manganese oxide (MnO2) guided with an oligopeptide as template. The synthetic nanocomposites can be co-assembled efficiently with the photosensitiser through π-π stacking interactions. Crucially, the mineralised MnO2 composition catalytically decomposes tumor-derived hydrogen peroxide to alleviate the hypoxic microenvironment, thereby improving the efficacy of the photosensitiser in ROS generation. In the murine model of 4 T1 xenograft tumors, the fabricated nanotherapeutics elicited robust antitumor immune responses and boost immunogenic phototherapy toward malignant tumors.

On the Origin of Capacity Increase in Rechargeable Magnesium Batteries with Manganese Oxide Cathodes and Copper Metal Current Collectors.

Rechargeable magnesium batteries (RMBs), with Cu as positive electrode current collector (CC), typically display a gradual capacity increase with cycling. Whereas the origin of this was suggested in gradual active material electro-activation, the fact that this is prevalent in many positive electrode material systems remains unexplained. Herein, we elucidate the underlying mechanism through a series of multiscale joint operando X-ray characterizations, including operando synchrotron X-ray diffraction and imaging technology. We select a series of manganese oxides as benchmark positive electrodes and find that no magnesium ions are stored within the lattices of these materials, despite an apparent cell capacity increase with cycling. The origin of capacity increase is rooted in the gradual electrochemical corrosion of metallic Cu, release of Cu(I, II) species in electrolyte, and their subsequent redox activity, resulting in apparent electrode capacity gains. Furthermore, the shuttle and redox speciation of Cu ions trigger the irreversible depletion of both the Cu CC (or any other source) and the magnesium metal, ultimately leading to cell failure. Our work suggests the need to reconsider the appropriateness of using Cu as a positive electrode CC for RMBs.

On the Origin of Capacity Increase in Rechargeable Magnesium Batteries with Manganese Oxide Cathodes and Copper Metal Current Collectors

Rechargeable magnesium batteries (RMBs), with Cu as positive electrode current collector (CC), typically display a gradual capacity increase with cycling. Whereas the origin of this was suggested in gradual active material electro‐activation, the fact that this is prevalent in many positive electrode material systems remains unexplained. Herein, we elucidate the underlying mechanism through a series of multiscale joint operando X‐ray characterizations, including operando synchrotron X‐ray diffraction and imaging technology. We select a series of manganese oxides as benchmark positive electrodes and find that no magnesium ions are stored within the lattices of these materials, despite an apparent cell capacity increase with cycling. The origin of capacity increase is rooted in the gradual electrochemical corrosion of metallic Cu, release of Cu(I, II) species in electrolyte, and their subsequent redox activity, resulting in apparent electrode capacity gains. Furthermore, the shuttle and redox speciation of Cu ions trigger the irreversible depletion of both the Cu CC (or any other source) and the magnesium metal, ultimately leading to cell failure. Our work suggests the need to reconsider the appropriateness of using Cu as a positive electrode CC for RMBs.

Basics and Advances of Manganese-Based Cathode Materials for Aqueous Zinc-Ion Batteries.

It is greatly crucial to develop low-cost energy storage candidates with high safety and stability to replace alkali metal systems for a sustainable future. Recently, aqueous zinc-ion batteries (ZIBs) have received tremendous interest owing to their low cost, high safety, wide oxidation states, and sophisticated fabrication process. Nanostructured manganese (Mn)-based oxides in different polymorphs are the potential cathode materials for the widespread application of ZIBs. However, Mn-based oxide materials suffer from several drawbacks, such as low electronic/ionic conductivity and poor cycling performance. To overcome these issues, various structural modification strategies have been adopted to enhance their electrochemical activity, including phase/defect engineering, doping with foreign atoms (e.g., metal and/or nonmetal atoms), and coupling with carbon materials or conducting polymers. Herein, this review targets to summarize the advantages and disadvantages of the above-mentioned strategies to improve the electrochemical performance of the cathodic part of ZIBs. The challenges and suggestions for the development of manganese oxides for ZIBs are put forward.

Influence of Thermomechanical Treatments and Chemical Composition on the Phase Transformation of Cu-Al-Mn Shape Memory Alloy Thin Sheets

This paper investigates the interrelated effects of thermomechanical treatments and chemical composition on the phase transformation capabilities of thin sheets made from Cu-Al-Mn shape memory alloys. The transformation capacity and transition temperatures were determined using DSC and DMA testing, while composition measurements were performed using SEM/EDX analysis. The results demonstrate that applying hot-rolling treatments to alloys of reduced thickness leads to manganese oxidation and modifications in chemical composition, adversely impacting the phase transformation performance. This effect can be mitigated by the use of cold rolling. Additionally, the presence of phosphorus impurities can create inclusions that bind manganese, preventing it from remaining in the solid solution and further affecting phase transformation capabilities.

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

Microscopic Investigation of CO Oxidation Reaction by Copper–Manganese Oxide Catalysts

Microscopic Investigation of CO Oxidation Reaction by Copper–Manganese Oxide Catalysts

Potent Amphiphilic Poly(Amino Acid) Nanoadjuvant Delivers Biomineralized Ovalbumin for Photothermal-Augmented Immunotherapy.

Cancer nanovaccines have emerged as an indispensable weapon for tumor treatment. However, insufficient immunogenicity and immunosuppression hamper the therapeutic effects of nanovaccines. Here, biodegradable nanovaccines (OMPP) composed of ovalbumin (OVA)-manganese oxide nanoparticles, amphiphilic poly(γ-glutamic acid) (γ-PGA), and ε-polylysine (PL) are constructed to realize enhanced cancer immunotherapy. Interestingly, amphiphilic γ-PGA and PL could serve as both carriers and immunoadjuvants to promote the cytosolic delivery of antigens and enhance the maturation of dendritic cells. Additionally, taking advantage of the photothermal property of OMPP, immunogenic cell death and in situ release of tumor-associated antigens can be triggered under near-infrared light irradiation for personalized tumor treatment. Moreover, OMPP nanovaccines can efficiently alleviate tumor hypoxia and downregulate programmed death-ligand 1 expression to reprogram the immunosuppressive tumor microenvironment. OMPP-mediated therapy has been shown to provoke robust immune responses to suppress B16-OVA melanoma and prevent postsurgical tumor recurrence. This work presents a facile strategy for the fabrication of nanovaccines by integrating carrier and adjuvant while exploring the inherent properties to promote antigen release and modulate immunosuppression, which demonstrates great potential for effective cancer immunotherapy.

Sodium-Rich, Co-Ni-Free P2-Layered Manganese Oxide Cathodes for Sodium-Ion Batteries.

The rapid capacity loss attributed to irreversible phase reactions and structural instability has consistently affected the development of P2-layered cathode materials. Moreover, the introduction of costly elements such as single or multiple dopants has failed to resolve the sustainability challenges in designing an optimal Mn-based layered oxide cathode. This study proposes a Co-Ni-free, poly-elemental doping strategy (Li, Mg, and Cu) combined with high sodium content for an Mn-based P2-layered cathode designed for Na+ ion storage. In situ X-ray diffraction analysis confirms the absence of P2 - O2 phase transitions during cycling for both NLMMC87 (Na0.87Li0.1Mg0.1Mn0.7Cu0.1O2) and NLMMC77 (Na0.77Li0.1Mg0.1Mn0.7Cu0.1O2). This can be attributed to the co-substitution of the electronegative Cu element and the stabilizing dopants Li and Mg, which suppress oxygen evolution. Simultaneously, the high sodium content within the host structure promotes high reversible capacity, enhances structural stability, and minimizes internal stress due to volume changes. Moreover, NLMMC87 demonstrates a reversible capacity of 167.9mA h g-1 at 0.1 C (97% Coulombic efficiency) and maintains excellent stability across various current rates. Further investigations into the practical application of NLMMC87 in a sodium full cell will be a critical step toward realizing an ideal cathode for sodium-ion batteries.

Catalase-peroxidase StKatG2 from Salinicola tamaricis: a versatile Mn(II) oxidase that decolorizes malachite green

Manganese (Mn) oxidation processes have garnered significant attention recently due to their potential for degrading organic pollutants. These processes are primarily catalyzed by Mn(II) oxidases. Salinicola tamaricis F01, an endophytic bacterium derived from wetland plants, has demonstrated Mn(II)-oxidizing capacity. In this study, a catalase-peroxidase, StKatG2, was cloned and overexpressed in Escherichia coli from the strain F01. The purified recombinant StKatG2 exhibited Mn(II)-oxidizing activity with Km and Kcat values of 2.529 mmol/L and 2.82 min−1, respectively. Optimal catalytic conditions for StKatG2 were observed at pH 7.5 and 55°C, with 45.1% activity retention after an 8-h exposure to 80°C. The biogenic manganese oxides produced by StKatG2 exhibited mixed-valence states with Mn(II), including Mn(III), Mn(IV), and Mn(VII). Furthermore, StKatG2 demonstrated superior decolorization efficiency for malachite green (MG), achieving decolorization rates of 73.38% for 20 mg/L MG and 60.08% for 50 mg/L MG, while degrading MG into 4-(dimethylamino)benzophenone. Therefore, the catalase-peroxidase StKatG2 exhibits multifunctionality in Mn(II)-oxidizing activity and has the potential to serve as an environmentally friendly enzyme for MG removal.

Enhancing the potassium-ion storage performance of potassium manganese oxide cathode by single-element doping strategies

Layered manganese-based oxides are considered as ideal cathode materials for potassium-ion batteries (PIBs) due to their ease of synthesis and relatively large interlayer spacing. Nevertheless, the Jahn-Teller effect of Mn3+ and the irreversible phase transitions in high-voltage regions of layered manganese-based oxide leads to slow diffusion kinetics of potassium ions and severe capacity fading. Herein, a series of single-element doped manganese-based oxide cathodes K0.5Mn0.98X0.02O2 (X = Fe, Mg, Cu, Ti and Zn) are designed and investigated. The results demonstrate that trace doping with these elements stabilizes the layered structure of KMnO2 cathode materials, improves the diffusion coefficient of K+, and effectively suppresses the P3-O3-P3 phase transition in high-voltage regions. Among the doping-samples, the K0.5Mn0.98Fe0.02O2 exhibits outstanding reversible specific capacity of 127 mAh g−1 at a current density of 20 mA g−1. Meanwhile, K0.5Mn0.98Ti0.02O2 demonstrates exceptional cycling stability and rate capability, retaining 83.8 % of its initial capacity after 300 cycles at 200 mA g−1, and maintaining a high specific capacity close to 40 mAh g−1 even at 1000 mA g−1. This study validates the feasibility of trace element doping in enhancing the electrochemical performance of layered Mn-based cathode materials for PIBs.

Improved MnO2 based electrode performance arising from step by step heat treatment during electrodeposition of MnO2 for determination of paracetamol, 4-aminophenol, and 4-nitrophenol

The design of electrochemical sensors is crucial considering important factors such as efficiency, low cost, biocompatibility, and availability. Manganese oxides are readily available, low-cost, and biocompatible materials, but their low conductivity limits their efficiency as sensors. Today, morphology engineering of manganese oxide has been one of the most common research topics, because manganese oxides’ electrochemical properties are highly dependent on their morphologies. In this study, a method for reducing the charge transfer resistance (Rct) of MnO2-based electrodes was established by the cyclic voltammetry technique accompanied by step-by-step heat treatment to electrodeposition MnO2 nanofilm, which remarkably improved the Rct. Next, the sensing performance of MnO2/FTO for two separate measurements was examined, one for the simultaneous measurement of paracetamol (PAR) and 4-aminophenol (4-APh), and the other for the measurement of 4-nitrophenol (4-NP). Under the optimum conditions, the linear ranges of 4-APh, PAR, and 4-NP, were 0.8 to 22.0 µM, 2.0 to 55.0 µM, and 0.1–250 µM, with limits of detection (LOD) of 0.19 µM, 0.60 µM, and 0.01 µM, respectively. It also was unaffected by a 200-fold excess of interferences. In addition, the designed sensor was successfully applied to the analysis of real samples.

Fabrication of MnO2-Modified Decellularized Tendon Membrane for Enhancing Tendon Repair.

Repairing tendon/ligament injuries is a major challenge in sports medicine. It has been reported that tendon injury healing is hindered by massive production of reactive oxygen species (ROS). Manganese oxides nanoparticles are generally non-toxic, can scavenge ROS, promote tissue regeneration, and hold promise for sustainable nanotechnologies. However, the effective and safe integration of MnO2 nanoparticles on decellularized scaffold mediating tissue repair is still a great challenge. To address these issues, an in situ MnO2-modified decellularized scaffold is developed to enhance tendon regeneration through improving microenvironment. The decellularized fibrous membrane is designed and prepared using the central tendon of the porcine diaphragm. Then MnO2 nanozymes are in situ grown on the collagen fibers using tannic acid (TA) as cross-linking agent and reducing agent. The results showed that MnO2-modified scaffold eliminates excessive accumulation of ROS in cells, protects mitochondrial, and maintains the phenotype of tendon cells in an oxidative stress environment. Notably, it is found that the MnO2-modified scaffold exhibits good biocompatibility and is able to promote the tendon healing in the rat patellar tendon defect model. Altogether, this study confirmed that this nanozyme-functionalized decellularized extracellular matrix effectively enhanced tendon repair by scavenging ROS, which provides new strategies for enhancing tendon regeneration.

Mechanisms of Thermal Decomposition in Spent NCM Lithium-Ion Battery Cathode Materials with Carbon Defects and Oxygen Vacancies.

Resource recovery from retired electric vehicle lithium-ion batteries (LIBs) is a key to sustainable supply of technology-critical metals. However, the mainstream pyrometallurgical recycling approach requires high temperature and high energy consumption. Our study proposes a novel mechanochemical processing combined with hydrogen (H2) reduction strategy to accelerate the breakdown of ternary nickel cobalt manganese oxide (NCM) cathode materials at a significantly lower temperature (450 °C). Particle refinement, material amorphization, and internal energy storage are considered critical success factors for the accelerated decomposition of NCM cathode materials. In our proposed approach, NCM cathode materials can develop active sites with carbon defects (Cv) and oxygen vacancies (Ov), which improve the reduction and breakdown of H2. The adsorbed H2 on the surface of NCM decomposes into H* and combines with oxygen to form OH species, which can be facilitated by Ov via the enhanced charge transfer. The introduced Cv can enhance H2 cracking and generate *C-H species to promote the thermal decomposition of NCM. The presence of defects proves to foster the preferential reduction of Mn(IV) by H2, leading to a lower activation energy for the NCM decomposition (from 139 to 110 kJ/mol) with less H2 consumption. Life cycle assessment suggests a reduction of 4.42 kg CO2 eq for the recycling of every 1.0 kg of retired batteries. This study can promote material circularity and minimize the environmental burden of mining technology-critical metals for a low-carbon transition.

Thermal hazard comparison and assessment of Li-ion battery and Na-ion battery

Na-ion batteries are considered a promising next-generation battery alternative to Li-ion batteries, due to the abundant Na resources and low cost. Most efforts focus on developing new materials to enhance energy density and electrochemical performance to enable it comparable to Li-ion batteries, without considering thermal hazard of Na-ion batteries and comparison with Li-ion batteries. To address this issue, our work comprehensively compares commercial prismatic lithium iron phosphate (LFP) battery, lithium nickel cobalt manganese oxide (NCM523) battery and Na-ion battery of the same size from thermal hazard perspective using Accelerating Rate Calorimeter. The thermal hazard of the three cells is then qualitatively assessed from thermal stability, early warning and thermal runaway severity perspectives by integrating eight characteristic parameters. The Na-ion cell displays comparable thermal stability with LFP while LFP exhibits the lowest thermal runaway hazard and severity. However, the Na-ion cell displays the lowest safety venting temperature and the longest time interval between safety venting and thermal runaway, allowing the generated gas to be released as early as possible and detected in a timely manner, providing sufficient time for early warning. Finally, a database of thermal runaway characteristic temperature for Li-ion and Na-ion cells is collected and processed to delineate four thermal hazard levels for quantitative assessment. Overall, LFP cells exhibit the lowest thermal hazard, followed by the Na-ion cells and NCM523 cells. This work clarifies the thermal hazard discrepancy between the Na-ion cell and prevalent Li-ion cells, providing crucial guidance for development and application of Na-ion cell.

Flexible electrochemical sensor based on N-doped helical carbon nanotubes coated manganese oxide nanoparticles for real-time monitoring of cellular hydrogen peroxide release

Flexible electrochemical sensor based on N-doped helical carbon nanotubes coated manganese oxide nanoparticles for real-time monitoring of cellular hydrogen peroxide release

Numerical investigation of the influence of thermal runaway modelling on car park fire hazard and application to a Lithium-ion Manganese Oxide battery

This article presents numerical simulations of a Nissan LEAF 2011 electric car fire inside a concrete parking facility. Variations in the thermo-chemical properties of thermal runaway are analysed, and the way they affect the heat received by the concrete structure and a nearby parked vehicle is evaluated. Three key parameters are identified: the composition of the gas flowing through the pressure vent, the associated flow rate, and the peak heat release rate. These parameters are established independently, and the model is closed by adjusting the stoichiometry of the combustion reaction of the vented gas. Four simulations are conducted to capture the uncertainty. The net heat flux and surface temperature on the concrete and on a neighbouring parked car are monitored during each simulation. The study includes a sensitivity analysis of the impact of input variables on the net heat fluxes and surface temperatures, and investigations are carried out to understand the role of internal heat release. Variations in the gaseous mixture composition, heat release rate, and internal heat release have little impact on the resulting thermal conditions around the burning car because the combustion of the polymers in the passenger cabin drives the total heat release rate.

Exploration of electrical conduction mechanisms via modulating sintering period of La0.67Ca0.33MnO3 films in various phase regions

Perovskite manganese oxide films have garnered significant attention due to their unique and diverse physical properties. In this work, La0.67Ca0.33MnO3 (LCMO) films are prepared on LaAlO3 (00l) substrates using the sol−gel spin coating method with varying sintering period (Ps). By optimizing Ps, improvements were observed in the films’ structure, morphology, ionic valence, and temperature−dependent resistivity. The reduction in Mn−O bond length and the increase in Mn−O−Mn bond angle change the degree of MnO6 distortion, resulting in an increased eg bandwidth. As Ps increased, the LCMO films exhibited better crystalline quality. The improved Mn4+/Mn3+ ratio strengthened the double exchange effect, facilitating the carrier hopping of the eg electrons. Analyses of various electrical conduction mechanisms showed that optimized electron scattering behavior, reduced hopping distance, energy and theoretical Curie temperature collectively enhance the temperature coefficient of resistivity (TCR) of LCMO films under optimal Ps. The TCR of the LCMO films reached a maximum value (31.64 % K−1) at Ps = 18 min. These findings offer valuable insights into the main electrical conduction mechanisms in both metallic and semiconducting phases, providing a deeper understanding of the underlying physical processes and offering experimental guidance for optimizing the electrical transport properties of perovskite films.

Optimizing Glass Foam Production from Recycled Sources: Influence of Variation in Cullet Color and Spent Alkaline Battery Components

Glass foams present a compelling opportunity for upcycling glass waste, offering a favorable combination of low weight, thermal insulation, and mechanical strength. Prior works demonstrated the feasibility of producing glass foams from glass waste and foaming agents sourced from synthetic textile waste, manganese oxides, and spent alkaline battery cathodes. This work explores the optimization of the process, investigating the impact of glass composition of differently colored glasses on final properties and incorporating entire alkaline batteries, encompassing both cathode and anode components. By carefully adjusting the composition, foaming agent content, and process temperature, customizable properties are achieved. Increasing foaming agent content or utilizing transparent glass improves insulation but lowers density and mechanical properties. Lowering foaming agent content or using brown/green glass enhances density and strength at the expense of insulation. Temperatures beyond 900 °C increase crystalline content, boosting mechanical performance without affecting density. This innovative approach not only offers a pathway to sustainable insulation materials but also underscores the potential for minimizing environmental impact through the efficient upcycling of glass waste.