以高锰酸钾为锰源反应得到的二维六方型氧化锰

Lithium manganese oxides with a two-dimensional layered crystal structure are of high fundamental and technological interest as cathode materials for rechargeable lithium-ion batteries, due to the safety, low cost, and low toxicity of manganese-based materials. However, basic problems such as the collapse of the layer structure during cycling of the battery have proven difficult to solve. This collapse usually leads to poor rate performance and to evolution of steps in the voltage profile, both of which are undesirable for practical applications. This article highlights important recent work on stabilization of the layered crystal structure of lithium manganese oxide. In particular we focus on the use of layered manganese oxide as a base for developing novel complex solid–solution cathode materials with improved capacity, cycling stability, and safety.

… to Mn 3 O 4 /MnO with the reduction of the Mn oxidation state… weaker and broader XRD peaks of Mn 3 O 4 (JCPDS no. 24-… of manganese ferrite due to the nanoscale mixing of Mn and …

With the rapid development of portable devices and wireless\nprotocols,\nminiaturized energy storage units have become an important prerequisite.\nAlthough in-plane microsupercapacitors are emerging as competitive\ncandidate devices, their practical applications have been severely\nhindered by their low energy density. Here, employing pseudocapacitive\nactive materials working in complementary voltage windows, namely,\nmanganese oxide (MnO2) and titanium carbide (Ti3C2), both in the two-dimensional sheet morphology, a flexible\nasymmetric interdigitated solid-state microsupercapacitor was assembled.\nProfiting from the perfect voltage complementarity of the two types\nof sheets, the high exposure of electrochemically active sites and\nthe maximized utilization of the sheets due to the planar ion transport,\nthe designed device achieved excellent electrochemical performance\neven when using a gel electrolyte. In particular, the device obtained\na high specific capacitance of 106 F g–1 (295 mF\ncm–2), a wide potential window (2 V), an ultrahigh\nrate performance (retaining 83% even with a 20-fold in current density\nto 20 A g–1), an excellent cycling stability (87%\nretention after 104 cycles at 10 A g–1), and a competitive energy density of 58 W h kg–1 (162 μW h cm–2) that are even comparable\nto those of some microbatteries, while maintaining a high power density\nof 985 W kg–1 (2.7 mW cm–2). Importantly,\nthis outstanding electrochemical performance was also stably maintained\nunder various bending conditions. These results indicate that two-dimensional\npseudocapacitive sheet materials have a plethora of possibilities\nfor constructing flexible and wearable devices.

Hierarchical and interpenetrating three-dimensional (3D) hollow MnO 2 /C composites have been successfully prepared via a facile and rapid dipping method.

… Nevertheless, few studies on aqueous MnO2 inks have been reported to date.[6] Herein, we … MnO2 ink comprised of hexagonal MnO2 nanosheets (hMnNSs). The aqueous MnO2 ink …

… the synthesis of functional oxide nanosheets, for example, Ti … precursor crystals of a layered oxide into its elementary layers. … -dimensional hexagonal architecture of MnO 2 nanosheet. …

We have successfully\ngrown hexagonally developed KxMnO2 single crystals (50 μm in lateral\nsize and 10 μm in thickness) by slow cooling from 1273 to 1173\nK at a rate of 0.5 K/h using K2MoO4 as a flux\nsource. To obtain large-sized MnO2 nanosheets from these\nKxMnO2 single crystals, we\ninvestigated an appropriate process to suppress cracking in the soft-chemical\ndelamination process. Crystals with fewer cracks were obtained upon\nreacting KxMnO2 with (NH4)2S2O8. The protonated crystals\nwere found to undergo massive swelling upon contact with a tetramethylammonium\nhydroxide solution. The swollen crystals were exfoliated into unilamellar\nMnO2 nanosheets by subsequent treatment with tetrabutylammonium\nions. The nanosheets were several micrometers in lateral sizes, larger\nthan those obtained from polycrystalline birnessite samples, and they\nhad a torn texture due to etching defects.

… This does not necessarily indicate that the nanosheet is amorphous, that is, loss of hexagonal atomic arrangement. Rather, the results suggest a beam-sensitive nature for the extremely …

… refers to the hexagonal symmetry of the host layer of bulk layered manganese oxide. Mn−Mn … information on the structure of manganese oxide nanosheets in the molecular state, which …

… The MnO 2 nanosheets have a hexagonal two-dimensional unit cell (a ∼ 0.3 nm) that … In summary, multilayer ultrathin films composed of novel manganese oxide nanosheets and …

We report in this paper the studies on protonation, exfoliation, and self-assembly of birnessite-type manganese oxide single crystals. The protonation was carried out by extracting K+ ions from the potassium manganese oxide single crystals in a (NH4)2S2O8 aqueous solution heated at 60 °C, exfoliation to nanosheets by the intercalation of TMA+ ions followed by water-washing, and the self-assembly of MnO2 nanosheets in a dilute NaCl solution. The structures of the samples at these stages were systematically investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared, thermogravimetric analysis-differential thermal analysis, and chemical compositional analysis. Electron density distribution in the protonated single crystal was visualized by whole-pattern fitting based on the maximum entropy method. The results indicated that the protonated single crystals can be exfoliated to MnO2 u...

… of potassium permanganate solutions. Taking this into account, for a more detailed analysis of the influence of the method of functionalization of MWCNTs on the features of their …

… layered manganese oxide, we were successful in synthesizing porous intercalative nanohybrids of ZnO-layered manganate and TiO 2 -layered manganate. … potassium manganate. All of …

… layered cathode materials. However, few efforts have been devoted to exploiting the co-intercalation of dual metal ions in the layered manganese oxide… of potassium permanganate and …

… manganese dioxide from potassium permanganate directly as the ranciete synthesis procedure was reported to lead to a large number of manganese … layered potassium manganate K,,,…

… , and potassium permanganate (KMnO 4 ) was obtained from Sinopharm Chemical Reagent Co., Ltd. All chemicals were used as received without further purification or treatment. …

Birnessite is a layered MnO2 mineral capable of intercalating\nnanometric water films in its bulk. With its variable distributions\nof Mn oxidation states (MnIV, MnIII, and MnII), cationic vacancies, and interlayer cationic populations,\nbirnessite plays key roles in catalysis, energy storage solutions,\nand environmental (geo)­chemistry. We here report the molecular controls\ndriving the nanoscale intercalation of water in potassium-exchanged\nbirnessite nanoparticles. From microgravimetry, vibrational spectroscopy,\nand X-ray diffraction, we find that birnessite intercalates no more\nthan one monolayer of water per interlayer when exposed to water vapor\nat 25 °C, even near the dew point. Molecular dynamics showed\nthat a single monolayer is an energetically favorable hydration state\nthat consists of 1.33 water molecules per unit cell. This monolayer\nis stabilized by concerted potassium–water and direct water–birnessite\ninteractions, and involves negligible water–water interactions.\nUsing our composite adsorption–condensation–intercalation model, we predicted humidity-dependent water loadings in terms of\nwater intercalated in the internal and adsorbed at external basal faces, the proportions of which vary with particle\nsize. The model also accounts for additional populations condensed on and between particles. By describing the nanoscale hydration\nof birnessite, our work secures a path for understanding the water-driven\ncatalytic chemistry that this important layered manganese oxide mineral\ncan host in natural and technological settings.

… of layered vanadium oxide can be synthesized through a simple hydrothermal reaction between potassium permanganate … manganese oxide could be found suggested that a layered K-…

… We are interested in the swelling and delamination behaviors of layered manganese oxides… prepared by the reduction of tetraalkylammonium permanganate; their fine structures have …

A novel synthesis method was developed to prepare manganese dioxide via cathodic electrolysis in potassium permanganate solution. The morphology and the composition of the synthesized products were analyzed by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction spectroscopy (XRD). The electrolyzed products include two kinds of materials: amorphous and crystalline manganese dioxide. The manganese dioxides were formed by cathodic reduction via two reaction mechanisms: direct and indirect electrochemical reactions. The electrolysis current performance strongly depends on the electrolyte solution temperature, applied voltage and not clearly depends on electrolyte solution concentration. With high current performance and uniformity products, the cathodic reduction of potassium permanganate is promising method for manganese dioxide fabrication.

… On the other hand, there is a growing interest in the study of manganese oxides as a result of, … Therefore, we synthesized the birnessite-type Manganese oxide (γ-MnO 2 ) nano-particles …

Layered birnessite sodium manganese dioxide exhibits a highly pseudocapacitive sodium storage behavior with non-phase changes in non-aqueous systems, leading to high rate and long-life performance.

… -MnO 2 showed some intermediate behavior between birnessite and 1D tunnel structures [43]. … method to synthesize Na-birnessite nanoplates and sodium manganese oxide nanobelts …

… The majority of papers report the formation of birnessite in powder form by oxidation of Mn(II) cations by KMnO4, H2O2, … synthesized pseudocapacitive manganese oxide films by anodic …

Birnessite is one of the most important manganese oxides that can control the geochemical behaviors of pollutants or can be applied to form industrial products. Many studies have been conducted on the synthesis of hexagonal birnessite because different synthesis methods can affect the structural, morphological, and physicochemical properties of hexagonal birnessite. However, there are still some defects in these synthesis methods. Therefore, a new synthesis method that is rapid, simple, and low-cost was proposed in this study involving the reduction of KMnO4 by H2O2 in a H2SO4 solution without controlling the pH, temperature and pressure. Using a series of XRD, chemical composition, AOS, SSA, SEM, FTIR, and TGA analyses, Bir-H2O2 was found to have lower crystallinity than Bir-HCl. However, the AOS and SSA of Bir-H2O2 were 3.87 and 103 m2 g−1 higher than those of Bir-HCl, i.e., 3.70 and 22 m2 g−1, respectively. Moreover, both Bir-H2O2 and Bir-HCl had similar particle morphology and thermal stability; in addition, the maximum adsorption content of Pb2+ on Bir-H2O2 (∼3006 mmol kg−1) was ∼30% greater than that on Bir-HCl (∼2285 mmol kg−1) at pH 5.5; this indicated that the adsorption of Pb2+ on Bir-H2O2 was better and belonged to a pseudo-second-order model. All the abovementioned results indicate that Bir-H2O2 synthesized herein using the proposed synthesis method can have large application value.

We present a study on the pseudocapacitive properties of birnessite-type MnO2 grafted on highly graphitized onion-like carbon (OLC/MnO2). In a three-electrode setup, we evaluated two different substrates, namely a platinum disc and nickel foam. The OLC/MnO2 nanohybrid exhibited a large specific capacitance (Csp) of 295 and 323 F g−1 (at 1 A g−1) for the Pt disc and Ni foam, respectively. In addition, the Ni foam substrate exhibited much higher rate capability (power density) than the Pt disc. A symmetrical two-electrode device, fabricated with the Ni foam, showed a large Csp of 254 F g−1, a specific energy density of 5.6 W h kg−1, and a high power density of 74.8 kW kg−1. These values have been the highest for onion-based electrodes so far. The device showed excellent capacity retention when subjected to voltage-holding (floating) experiments for 50 h. In addition, the device showed a very short time constant (τ = 40 ms). This high rate handling ability of the OLC/MnO2 nanohybrid, compared to literature reports, promises new opportunities for the development of aqueous-based pseudocapacitors.

Several Mn oxide minerals commonly occurring in soils were synthesized by modified or optimized methods. The morphologies, structures, compositions and surface properties of the synthesized Mn oxide minerals were characterized. Adsorption and redox reactions of heavy metals on these minerals in relation to the mineral structures and surface properties were also investigated. The synthesized birnessite, todorokite, cryptomelane, and hausmannite were single-phased minerals and had the typical morphologies from analyses of XRD and TEM/ED. The PZCs of the synthesized birnessite, todorokite and cryptomelane were 1.75, 3.50 and 2.10, respectively. The magnitude order of their surface variable negative charge was: birnessite> or =cryptomelane>todorokite. The hausmannite had a much higher PZC than others with the least surface variable negative charge. Birnessite exhibited the largest adsorption capacity on heavy metals Pb(2+), Cu(2+), Co(2+), Cd(2+) and Zn(2+), while hausmannite the smallest one. Birnessite, cryptomelane and todorokite showed the greatest adsorption capacity on Pb(2+) among the tested heavy metals. Hydration tendency (pK(1)) of the heavy metals and the surface variable charge of the Mn minerals had significant impacts on the adsorption. The ability in Cr(III) oxidation and concomitant release of Mn(2+) varied greatly depending on the structure, composition, surface properties and crystallinity of the minerals. The maximum amounts of Cr(III) oxidized by the Mn oxide minerals in order were (mmol/kg): birnessite (1330.0)>cryptomelane (422.6)>todorokite (59.7)>hausmannite (36.6).

… The present work concentrates on measurements of enthalpies of formation and surface energies of synthetic birnessite and cryptomelane phases to explain these frequently observed …

… Mn oxide minerals are ubiquitous in soils and sediments and … and birnessite, two of the more common Mn oxide minerals … of Mn oxide minerals and to prepare synthetic analogues …

… the characteristic diffraction peaks of the birnessite-type manganese oxide crystal (JCPDS 23-… layered birnessite and manganese ferrite to a mixture of various forms including birnessite, …

Hydrazine is a common reducing agent widely used in many industrial and chemical applications; however, its high toxicity causes severe human diseases even at low concentrations. To detect traces of hydrazine released into the environment, a robust sensor with high sensitivity and accuracy is required. An electrochemical sensor is favored for hydrazine detection owing to its ability to detect a small amount of hydrazine without derivatization. Here, we have investigated the electrocatalytic activity of layered birnessite manganese oxides (MnO2) with different intercalants (Li+, Na+, and K+) as the sensor for hydrazine detection. The birnessite MnO2 with Li+ as an intercalant (Li-Bir) displays a lower oxidation peak potential, indicating a catalytic activity higher than the activities of others. The standard heterogeneous electron transfer rate constant of hydrazine oxidation at the Li-Bir electrode is 1.09- and 1.17-fold faster than those at the Na-Bir and K-Bir electrodes, respectively. In addition, the number of electron transfers increases in the following order: K-Bir (0.11 mol) < Na-Bir (0.17 mol) < Li-Bir (0.55 mol). On the basis of the density functional theory calculation, the Li-Bir sensor can strongly stabilize the hydrazine molecule with a large adsorption energy (-0.92 eV), leading to high electrocatalytic activity. Li-Bir also shows the best hydrazine detection performance with the lowest limit of detection of 129 nM at a signal-to-noise ratio of ∼3 and a linear range of 0.007-10 mM at a finely tuned rotation speed of 2000 rpm. Additionally, the Li-Bir sensor exhibits excellent sensitivity, which can be used to detect traces of hydrazine without any effect of interference at high concentrations and in real aqueous-based samples, demonstrating its practical sensing applications.

… The layered monocrystalline NaMnO nanosheets with hexagonal structure was Synthesis by conventional molten salt-assisted method. In particular, 3 g of sodium nitrate (NaNO 3 ) …

… The XRD pattern is indexed as a hexagonal unit cell and has intense (00l) reflections … assay based on the inner filter effect of MnO2 nanosheets on vitamin B2. Spectrochimica Acta Part …

… of g-MnO2 irregular nanosheets and g-MnO2 hexagonal … of hexagonal symmetry in the synthesized g-MnO2 hexagon-… –ramsdellite intergrowth model for g-MnO2. Due to the small size …

… manganese oxide catalyst often involves three main processes: (i) wet impregnation of the support with an aqueous solution containing manganese precursor … the potassium manganate …

… In the current study, we have reported the controllable synthesis of manganese oxide nanorods via a fast acidic reaction of potassium permanganate and heat treatment. The effect of K+ …

Abstract Mn-based catalysts have been widely studied for the oxidation of volatile organic compounds (VOCs) and appear to be the most active catalysts among the transition metal oxides. In this study, manganese oxides are supported on halloysite, a nanoscale and porous clay mineral, by an impregnation method using manganese nitrate, manganese acetate, and potassium permanganate as precursors. The nitrate results in scattered 35–249 nm agglomerates of pyrolusite (β-MnO2) on the external surface of the halloysite nanotubes; the acetate produces hausmannite (Mn3O4) particles with sizes of 15–40 nm dispersed on the external surface, while the permanganate creates nanoparticles and agglomerates of amorphous K-containing MnO2 on the external surface as well as in the lumen. These differences in structure and distribution are related to the oxidizability of the precursor, surface charge and the cylindrical lumen of halloysite, and the interaction between manganese ions (Mn2+ or MnO4−) and the surface groups of halloysite (Si O Si or Al OH). The obtained samples were tested for the thermal catalytic oxidation of formaldehyde. The halloysite-supported manganese oxide with the permanganate precursor exhibits the best activity and achieves 90% of CO2 generation at 149 °C. The activity of formaldehyde oxidation is positively correlated to the reducibility, which depends on the phase, oxidation state, and dispersion of manganese oxides. This study illuminates the constraint of the manganese precursor on halloysite-supported manganese oxides for the thermal catalytic oxidation of formaldehyde and will be beneficial for the development of transition metal oxide-based catalysts in the abatement of VOCs.

Abstract Manganese oxide nanoflowers were synthesized by a simple hydrothermal method at 150 °C and 170 °C temperature using potassium permanganate (0.1 M and 0.3 M) as manganese source and cetyltrimethylammonium bromide (0.05 M) as size reducing reagent. A reaction duration of 12 h was used in all the experiments. The synthesized product consists of the mixed phases of cubic Mn2O3 and orthorhombic Mn3O4 systems as analyzed from X-ray diffraction studies. Fourier transform infrared spectroscopic studies confirmed the presence of Mn-O bond. High resolution transmission electron microscopic images show the formation of nanoflower structures. The average diameter of the nanoflowers is ∼771 nm. The influence of reaction temperature and molar concentration of potassium permanganate on the morphology of manganese oxide was studied by field emission scanning electron microscopy.

… The purpose of this study was to evaluate the effect of the precursors on the synthesis of … with potassium permanganate, the precursor contributes both manganese and potassium. Thus …

… used as precursor compounds for the thermal genesis (at 150~600C) of manganese oxides. … Model manganese oxides were subjected to similar examinations for reference purposes. …

… The present study focuses on the preparation of two manganese oxide materials having [… Potassium permanganate was added and kept under reflux by vigorous stirring for 24 h. The …

Transition metal-based materials have garnered considerable attention in the energy storage field owing to their diverse composition, abundant redox capacity and excellent thermal stability. However, the application of these materials as electrodes for aqueous electrochemical energy storage devices such as aqueous zinc-ion batteries (AZIBs) and supercapacitors (SCs) is impeded by their low conductivity and limited energy density. This challenge can be effectively addressed through structural optimizations of transition metal-based materials. In recent years, extensive research has been conducted on two-dimensional (2D) nanostructured transition metal-based electrodes in the context of AZIBs and SCs, thereby presenting promising prospects for 2D nanostructures of transition metal-based materials. This review provides a comprehensive overview of the synthesis methods for 2D nanostructured materials and presents research findings on 2D nanostructured transition metal-based electrodes in AZIBs and SCs. It analyzes the advantages of 2D nanostructures, focusing on transition metal oxides, hydroxides, and sulfides. Furthermore, it explores the correlation between their structural characteristics and electrochemical properties. Finally, we discuss the main challenges faced by 2D nanostructures of transition metal-based materials and outline future development prospects.

Layered materials with two‐dimensional ion diffusion channels and fast kinetics are attractive as cathode materials for secondary batteries. However, one main challenge in potassium‐ion batteries is the large ion size of K+, along with the strong K+−K+ electrostatic repulsion. This strong interaction results in initial K deficiency, greater voltage slope, and lower specific capacity between set voltage ranges for layered transition metal oxides. In this review, a comprehensive review of the latest advancements in layered cathode materials for potassium‐ion batteries is presented. Except for layered transition metal oxides, some polyanionic compounds, chalcogenides, and organic materials with the layered structure are introduced separately. Furthermore, summary and personal perspectives on future optimization and structural design of layered cathode materials are constructively discussed. We strongly appeal to the further exploration of layered polyanionic compounds and have demonstrated a series of novel layered structures including layered K3V2(PO4)3.

… -type MnO 2 , also denoted as δ-MnO 2 in the literature, has a two-dimensional (2D) … and crystal phase from birnessite-type MnO 2 with a microsphere/nanosheet core−corona …

Abstract Exfoliation of non‐layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top‐down method to exfoliate ϵ‐MnO 2 nanosheets in a family of charge‐ordered La 1− x AE x MnO 3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn–Teller disproportionation effect of Mn 3+ and bond‐strength differences. ϵ‐MnO 2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton‐induced Mn 3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two‐dimensional nanosheet materials with non‐layered structures.

… Birnessite-type MnO 2 (δ-MnO 2 ) possess a two-dimensional lamellar structure with an … At present, lamellar structures of birnessite-type MnO 2 nanosheets have been fabricated by …

… synthesis of a hexagonal form of manganese dioxide using mild hydrothermal methods. The … at 170 C leads directly to potassium or sodium manganese dioxide, Alk ≈0.25 MnO 2 ·0.6H …

… of a series of kinetically stable manganese dioxide samples via a dissolution-precipitation … forms can be described as a hexagonal close-packed array of oxide ions in which half of the …

… manganese oxide spheres of hexagonal birnessite K–OL with molecular formula of K 0.27 MnO 2 · 0.54H 2 O was prepared by a simple hydrothermal treatment … in hydrothermal system. …

… 7 Schematic representation of hexagonal mesoporous manganese oxide (MOMS-1) and … the large ion synthesis of large tunnel manganese oxides in the hydrothermal Cs+.59 The large …

SummaryA 1 M solution of potassium permanganate was sealed in a gold capsule and was treated under conditions of temperature and pressure up to 800 °C and 2·5 kb. Different kinds of products were produced under different conditions of synthesis, and potassium manganate, birnessite, cryptomelane, hausmannite, manganosite, and a new phase appeared. The chemical composition of the new phase was determined as K2Mn4O9 and its X-ray powder diffraction pattern was indexed on a hexagonal cell with a 11·295 and c 21·870 Å.

… to a pure hexagonal phase of γ-MnO2 (Joint Committee on Powder Diffraction Standards (JCPDS) card 17-510) for the sample formed at a hydrothermal treatment temperature of 120C (…

The peculiar physical\nand chemical properties of 2D nanostructures\nhave aroused global research interest in developing new members, synthetic\ntechnology, and exploring their potential applications in functional\nnanodevices. However, it is extremely challenging to directly obtain\nthe 2D nanosheets for these extrinsic layered structures using conventional\nroutines. In this work, we demonstrate the facile and general synthesis\nof 2D spinel-type metal oxides nanosheets through a simple hydrothermal\nreaction. Using this method, cubic γ-Ga2O3, ZnGa2O4 and MnGa2O4 nanosheets with triangular/hexagonal configuration and ultrathin\nthickness have been synthesized, and all these nanosheets show preferential\ngrowth along (111) plane with the minimum formation energy. Microstructural\nand composition analyses using HRTEM, EDS, XPS, and so on reveal that\nthe as-synthesized 2D nanosheets are well-crystallized in cubic fcc-phase\nand show high purity in composition, and the formation process of\nMGa2O4 nanosheets can be regarded as the competition\nof M2+ and Ga3+ in tetrahedral site. Spatially\nresolved cathodoluminescence measurement of individual 2D nanosheet\nshows that the γ-Ga2O3, ZnGa2O4, and MnGa2O4 nanosheets exhibit\ndistinct luminescence behavior, and ZnGa2O4 nanosheets\nshow the strongest emission in visible region. It is expected that\nthe facile synthesis of spinel-type metal oxides of γ-Ga2O3, ZnGa2O4, and MnGa2O4 nanosheets will further promote the exploration\nof a variety of semiconductor nanostructures that could not be achieved\nusing conventional technology suitable for layered structures and\nwill also open up some opportunities for the integration of advanced\nfunctional nanodevices such as photodetectors, phosphors on the basis\nof them.

… Manganese oxides were fabricated by hydrothermal … (TBAB) on manganese oxide crystal structures were investigated. … of manganese oxides were studied using oxidation of benzyl …

… We adopted the hydrothermal method because a preliminary … size can be obtained by hydrothermal reaction at a relatively … 0.5 Mn 1.5 ] 16d O 3.75 , and a model of a hexagonal lattice …

… materials studied in this work, suggesting that two-dimensional (2D) RGO sheets are an … of sp 2 -bonded carbon atoms in a two-dimensional hexagonal lattice, such as in graphene [24], […

… Graphene’s two-dimensional (2D) nature leads to a … (TMDs) and transition metal oxides, are also promising and are … MAX phases: layered, hexagonal carbides and nitrides that can …

ABSTRACT The critical need for safe, scalable grid‐scale energy storage has positioned aqueous zinc‐ion batteries (AZIBs) as a leading solution. However, their commercial deployment faces significant challenges: dendrite growth and corrosion at the anode, and dissolution and slow reaction kinetics at the cathode. Two‐dimensional (2D) layered materials, with their unique structural and chemical properties, are emerging as pivotal enablers to overcome these hurdles. This review systematically analyzes the multifunctional applications of 2D layered materials (graphene derivatives, MXenes, TMDs, etc.) as protective anode layers, high‐capacity cathode hosts, advanced separators, and electrolyte additives in AZIBs. We provide a mechanistic understanding of how 2D layered materials inhibit zinc dendrite formation, suppress the hydrogen evolution reaction (HER) and other side reactions, enhance cathode stability, and facilitate efficient ion transport. Finally, this review critically examines the key challenges and future research directions for implementing 2D layered materials in high‐performance AZIBs, providing new insights to guide their scalable production and commercial deployment.

We report the fabrication and performance of zinc oxide core/manganese oxide shell (ZnO/MnO 2 ) three-dimensional nanostructured planar supercapacitor. In this particular fabrication, …

This review summarizes pathways to obtain LDH nanosheets for various applications, provides an overview of the current understanding of mechanistic studies, and promotes a better understanding of the fundamental chemistry, which will in turn be beneficial for the wider scientific community, and will present potential future directions of the research areas.

… manganese oxides catalysts (MnO x /MCM-41) prepared from different manganese precursors (potassium permanganate, … different manganese precursors (potassium permanganate, …

… matters may be precursors of the disinfection … manganese dioxide produced in situ during permanganate preoxidation played an important role and suggested that manganese dioxide …

… have demonstrated that the DBPs precursors of NOM are major … oxidation could remove some organics adsorbed to the inner pore fibers or membrane surfaces and manganese dioxide…

… Oxidation by potassium permanganate and different photocatalytic methods have been tested. Solid and liquid residual potassium permanganate have been used to obtain an initial …

Abstract In 2011, a new family of two dimensional (2D) carbides, carbonitrides and nitrides – labeled MXenes – was discovered. Since then the number of papers on these materials has increased exponentially for several reasons amongst them: their hydrophilic nature, excellent electronic conductivities and ease of synthesizing large quantities in water. This unique combination of properties and ease of processing has positioned them as enabling materials for a large, and quite varied, host of applications from energy storage to electromagnetic shielding, transparent conductive electrodes, electrocatalysis, to name a few. Since the initial synthesis of Ti3C2 in hydrofluoric acid, many more compositions were discovered, and different synthesis pathways were explored. Most of the work done so far has been conducted on top-down synthesis where a layered parent compound is etched and then exfoliated. Three bottom-up synthesis methods, chemical vapor deposition, a template method and plasma enhanced pulsed laser deposition have been reported. The latter methods enable the synthesis of not only high-quality ultrathin 2D transition metal carbide and nitride films, but also those that could not be synthesized by selective etching. This article reviews and summarizes the most important breakthroughs in the synthesis of MXenes and high-quality ultrathin 2D transition metal carbide and nitride films.

… of manganese dioxides with controlled novel 3D architectures via a hydrothermal chemical reaction between manganese … to alternate along the c-axis of the hexagonal cell. The double …

… -embedded zeolite cluster, and model Mn oxides help to explain and interpret the diffuse … -containing ZSM-5 zeolite, which is composed of single crystals of intergrown hexagonal …