Manganese Oxide Nanocomposite Research Articles

Facile synthesis of silver doped manganese oxide nanocomposite with superior photocatalytic and antimicrobial activity under visible spectrum

Water pollution and antimicrobial resistance (AMR) have become two global threats; 80% of diseases and 50% of child deaths are due to poor water quality. In this study, hydrothermal processing was employed to manufacture manganese oxide nanorods. Silver dopant was deposited on the surface of manganese oxide. XRD diffractogram confirmed the facile synthesis of Ag/Mn2O3 nanocomposite. XPS survey analysis demonstrated silver content of 9.43 atom %. Photocatalytic measurements demonstrated the outstanding efficiency of the Ag-Mn2O3 compared to virgin oxide particles under visible radiation. Degradation efficiencies Mn2O3 and Ag/Mn2O3 on methyl orange (MO) dye was found to be 53% and 85% under visible spectrum. Silver dopant was found to decrease the binding energy of valence electrons; this action could support electron–hole pair generation under visible spectrum and could promote catalytic performance. Ag/Mn2O3 NPs demonstrated most effective performance (95% removal efficiency) at pH 3; this could be ascribed to the electrostatic attraction between positively charged catalyst and the negatively charged MO. Ag/Mn2O3 demonstrated enhanced antibacterial activity against Gram-positive Staphylococcus aureus (S. aureus) (19 mm ZOI), and Gram-negative Escherichiacoli (E. coli) (22 mm ZOI) respectively; the developed nanocomposite demonstrated advanced anti-film activity with inhibition percentage of 95.5% against E. coli followed by 89.5% against S. aureus.

Facile synthesis of silver doped manganese oxide nanocomposite with superior photocatalytic and antimicrobial activity under visible spectrum

Water pollution and antimicrobial resistance (AMR) have become two global threats; 80% of diseases and 50% of child deaths are due to poor water quality. In this study, hydrothermal processing was employed to manufacture manganese oxide nanorods. Silver dopant was deposited on the surface of manganese oxide. XRD diffractogram confirmed the facile synthesis of Ag/Mn2O3 nanocomposite. XPS survey analysis demonstrated silver content of 9.43 atom %. Photocatalytic measurements demonstrated the outstanding efficiency of the Ag-Mn2O3 compared to virgin oxide particles under visible radiation. Degradation efficiencies Mn2O3 and Ag/Mn2O3 on methyl orange (MO) dye was found to be 53% and 85% under visible spectrum. Silver dopant was found to decrease the binding energy of valence electrons; this action could support electron–hole pair generation under visible spectrum and could promote catalytic performance. Ag/Mn2O3 NPs demonstrated most effective performance (95% removal efficiency) at pH 3; this could be ascribed to the electrostatic attraction between positively charged catalyst and the negatively charged MO. Ag/Mn2O3 demonstrated enhanced antibacterial activity against Gram-positive Staphylococcus aureus (S. aureus) (19 mm ZOI), and Gram-negative Escherichiacoli (E. coli) (22 mm ZOI) respectively; the developed nanocomposite demonstrated advanced anti-film activity with inhibition percentage of 95.5% against E. coli followed by 89.5% against S. aureus.

Efficient removal of aqueous organic pollutants by well-ordered layered manganese oxide nanocomposites: Impacts of interlayer spacing and nanoconfinement

Although manganese oxide is able to spontaneously oxidize organic contaminants in nature, the slow kinetics limit its application in engineered water treatment processes. Herein, we prepared well-ordered layered manganese oxides (LMOs) with adjustable interlayer distances using cetyltrimethylammonium bromine as a guest molecule, which were applied to degrade 3-chlorophenol as an example of organic pollutants. The ordering of the layered structure was found to be highly dependent on the molar ratio of cetyltrimethylammonium ion (CTA+) to Mn in the solutions (range 0–1.2). The maximum interlayer spacing (11.27 Å) was obtained at a molar ratio was 1.0 (LMO-1.0), which reduces the steric hindrance for 3-chlorophenol entering the interlayers. Additionally, the surface of the LMOs becomes more hydrophobic as their molar ratio increased, further favors adsorption of 3-chlorophenol on the LMO-1.0. The LMO-1.0 provides a constrained reaction environment, which increases the probability of 3-chlorophenol interacting with the active species as well as promotes the production and enrichment of superoxide radical (O2•−). Consequently, the degradation rate constant of 3-chlorophenol (0.446 min−1) is two orders of magnitude higher compared to the unconfined bulk phase (0.004 min−1). These findings provide useful insights into the development of Mn-based layered materials for water purification.

Correction to: Fabrication and electrochemical performance of spinel copper manganese oxide nanocomposites for supercapacitor application

Correction to: Fabrication and electrochemical performance of spinel copper manganese oxide nanocomposites for supercapacitor application

Fabrication and electrochemical performance of spinel copper manganese oxide nanocomposites for supercapacitor application

Fabrication and electrochemical performance of spinel copper manganese oxide nanocomposites for supercapacitor application

Characterization of Mn3 O4 -MnO2 nanocomposites biosynthesized by cell lysate of Haloferax alexandrinus GUSF-1.

Manganese oxide nanocomposites attract huge attention in various biotechnological fields due to their extensive catalytic properties. This study reports an easy, rapid, and cost-effective method of using the cell lysate of haloarchaeon, Haloferax alexandrinus GUSF-1 for the synthesis of manganese oxide nanoparticles. The reaction between the cell lysate and manganese sulfate resulted in the formation of a dark brown precipitate within 48 h at room temperature. The X-ray diffraction pattern showed the existence of Mn3 O4 and MnO2 phases consistent with the JCPDS card no. (01-075-1560 and 00-050-0866). The dark brown colloidal suspension of MnO3 -MnO2 in methanol showed maximum absorption between 220 and 260 nm. The EDX spectrum confirmed the presence of manganese and oxygen. The Transmission electron microscopy revealed the spherical morphology with an average particle size between 30 and 60 nm. The magnetic moment versus magnetic field (MH) curve, at room temperature (300 K) did not saturate even at a high magnetic field (±3T) indicating the paramagnetic nature of the prepared nanocomposite. The Atomic Emission Spectroscopic analysis showed a negligible amount of soluble manganese (0.03 ppm in 50 ppm) in the Mn3 O4 -MnO2 suspension suggesting the maximum stability of the material in the solvent over time. Interstingly, Mn3 O4 -MnO2 nanocomposites evidenced antimicrobial activity in the order of Pseudomonas aeruginosa > Salmonella typhi > Escherichia coli > Proteus vulgaris > Candida albicans > Staphylococcus aureus. Conclusively, this is the first report on the formation of Mn3 O4 -MnO2 nanocomposites using cell lysate of salt pan haloarcheon Haloferax alexandrinus GUSF-1 with antimicrobial potential.

Enhanced electrochemical performance of manganese oxide nanocomposites for supercapacitor application

Enhanced electrochemical performance of manganese oxide nanocomposites for supercapacitor application

Structural Elucidation of Nitrogen-Doped Reduced Graphene Oxide/Hausmannite Manganese Oxide Nanocomposite for Supercapacitor Applications

The increasing consumption of fossils fuel accompanied by related carbon emissions and complex set of issues associated with the generation and use of electricity has raised an urgent need for reliable, renewable and sustainable energy alternatives [1]. Nanotechnology and the production of nanostructured materials has driven the rapid growth in the research of carbon nanomaterials as energy storage materials for supercapacitor (SCs) applications. Among several carbon nanomaterials explored for SCs, graphene has shown to be the leading carbon nanomaterial, due to its intriguing properties such as highly tunable surface area, outstanding electrical conductivity, good chemical stability and excellent mechanical behavior [2]. Due to challenges in the bulk synthesis of graphene, reduced graphene oxide (rGO) has been opted as the preferred choice for the development of SC devices. Transition metal oxides also gained much interest in various research industries as materials for SCs applications. Among transition metal oxides, manganese oxide, MnxOy, appeared to be the promising electrode material due to its interesting properties such as cost effectiveness, high theoretical specific capacitance, high theoretical surface area (≥ 1370 m2 g-1), and excellent electrochemical reversibility. However, the poor conductivity of manganese oxide restricts its progress in SC applications [2, 3]. Therefore, great attention has been devoted to the improvement of the electronic properties of manganese oxides-based electrode materials by decorating them on highly conductive carbon-based nanomaterials. Although intensive study has been done on carbon nanomaterials integrated with MnxOy for pseudocapacitors, there is still less literature on the use of Mn3O4 nanoparticles decorated on carbon materials for application in SCsThis work presents a hydrothermal synthesis of the nitrogen-doped reduced graphene oxide/hausmannite manganese oxide (N-rGO/Mn3O4) nanohybrid which showed a great electrochemical performance such as high specific capacitance of 345 F g-1 and a maximum of specific energy of 12.0 Wh kg-1 (current density: 0.1 A g−1), and a maximum specific power of 22.5 kW kg-1 (current density: 10.0 A g−1) in a symmetric configuration. The nanohybrid further showed excellent supercapacitor performance in an asymmetric configuration, with the maximum specific energy and power reaching 34.6 Wh kg−1 (0.1 A g−1) and 14.01 kW kg−1 (10.0 A g−1) respectively. The results obtained affirm the use of N-rGO/Mn3O4 as a potential electrode material for high energy and power supercapacitor devices that can be commercially competitive to that of rechargeable batteries.

Hierarchical structure and electronic effect promoted degradation of phenols over novel MnO2 nanoprisms via non-radical mechanism

In this work, a novel 3D hierarchical cryptomelane-type manganese oxide nanocomposite (APM-OMS-2) was prepared via pre-incorporation with ammonium phosphomolybdate (APM) as an additive for the first time. The APM dosage not only transferred the material morphology from 1D to 3D, but also affected the crystal phasze, textural properties and redox ability. APM-OMS-2 displayed a unique nanoprism morphology coated by APM as the outer-sphere and consisted of a hierarchical framework. The catalytic ability of APM-OMS-2 was examined by the degradation of phenolics via peroxymonosulfate (PMS) activation in various water matrix. The optimized catalytic system gave a 95 % degradation rate and a 83 % mineralization rate of 4-chlorophenol (20 mg/L) with 200 mg/L of APM-OMS-2 and 100 mg/L of PMS within 60 min. According the first-order kinetic study of 4-chlorophenol degradation, APM-OMS-2/PMS system gave a higher initial reaction rate constant at 0.2014 min−1 and a lower activation energy at 29.2 kJ/mol than OMS-2/PMS because its hierarchical structure and textural properties were beneficial to mass transfer, diffusion and reaction between catalyst and reactants. Characterizations further suggested that PMS activation was conducted by 1O2-mediated oxidation along with MnIV/MnIII redox cycles. Moreover, electrochemical analysis indicated that mediated electron transfer contributed to the catalytic performance via the outer-sphere electronic interaction of the core/shell nanocomposite. This study provides a very simple method for the synthesis of 3D cryptomelane-type MnO2 towards oxidative degradation of aqueous contaminants.

A screen printed methodology optimized by molecular dynamics simulation and Lean Six Sigma for the determination of xylometazoline in the presence of benzalkonium chloride in nasal drops.

A new chemically disposable screen-printed modified electrode with yttrium doped manganese oxide (Mn2O3/Y2O3) nanocomposite at screen printed electrode was mainly constructed to quantify xylometazoline hydrochloride (XMZ). The crystallographic parameters were estimated from the XRD spectrum, suggesting that Mn2O3 of cubic phase with average grain size ∼ 77nm. The SEM images revealed that Y3+ dopants had improved the surface topology. The findings indicate that morphological features play a vital role in improving the electronic properties of the fabricated electrode. Augmentation of Six Sigma (SS) with molecular dynamics simulation (MD) as a theoretical study was widely adopted to improve the current process as a quality management methodology by measuring the process capability to determine if the process meets the desired specification limits. Process capability is determined through measuring the variability in the process output and comparing these variations with the desired specifications. Also, it assures a robust method specification at a high level of targeted performance and statistical confidence. A greenness assessment procedure utilizing the eco-scale algorism was conducted to prove the greenness of the proposed methodology. Additionally, the proposed sensor presented a high sensitivity over the concentration range (1x10-6-1x10-2molL-1) of a detection limit 3.93×10-7molL-1 with the Nernstian cationic slope of 58.18±0.76mVdecade-1 at 25±1°C.

Green synthesis of a MnO-GO-Ag nanocomposite using leaf extract of Fagonia arabica and its antioxidant and anti-inflammatory performance

This research work includes the green synthesis of silver and graphene oxide doped manganese oxide nanocomposites (NCs) using Fagonia arabica, which is commonly found in Asian countries and widely grown in deserts. Fagonia arabica is a medicinal herb used for the treatment of a variety of diseases. Fagonia arabica shows efficient anti-inflammatory, antimicrobial activity and antioxidant properties. Manganese oxide (MnO) NPs were synthesized by a green synthesis method using leaf extract of Fagonia arabica. The synthesized manganese oxide nanoparticles (NPs) were then used to form manganese oxide composites coupled with graphene oxide (GO) and silver (Ag). The main composite synthesized in this research work is MnO-GO-Ag NCs. All the synthesized NPs and composites were then characterized by SEM, XRD, EDX and ultra-violet–visible spectroscopy. The anti-inflammatory activity of the manganese oxide NPs and their MnO-GO and MnO-GO-Ag composites were checked by UV-visible spectroscopy and the obtained results were compared with the standard Diclofenac Sodium. The antioxidant activity of MnO-GO-Ag shows a higher scavenging potential than the standard ascorbic acid. SEM analysis was performed to check the size and morphology of the obtained product. The XRD analysis confirmed the purity and crystallinity of synthesized MnO-GO-Ag NCs. EDX spectra showed the peaks for C, O, Ag and Mn, indicating the presence of these elements in our desired composite. For anti-inflammatory activity, the MnO-GO-Ag NCs showed percentage inhibitions of 34.15 and 81.71%, having an IC50 values of 0.15 and 0.23, at 0.1 and 0.5 mg/mL concentrations, respectively. MnO-GO-Ag showed percentage scavenging efficiencies of 59.84 and 74.48% at concentrations of 0.3 and 0.5 mg/mL, respectively, while the standard (ascorbic acid) showed scavenging potentials of 44.22 and 58.42% at similar concentrations. The MnO-GO-Ag NCs showed lower IC50 values, thus exhibit the high efficiency of the NCs for anti-inflammatory and antioxidant activities.

Manganese Oxide Nanocomposite for adsorption of Cd(II) Ions from Aqueous Phase: Optimization by Experimental Design

Manganese Oxide Nanocomposite for adsorption of Cd(II) Ions from Aqueous Phase: Optimization by Experimental Design

Preparation and characterization of boron doped CN’s/MnO2 and its photocatalytic application of dye degradation

Abstract Boron doped carbon nitrides (CN) manganese oxide (BCN/MnO2) nanocomposite is considered to be a visible light active photocatalyst and it is used for the removal of Rhodamine B. Boron doped at 5% in CN (BCN) was prepared by thermal condensation of melamine with boric acid and MnO2 nanoparticle was synthesized by hydrothermal method. As prepared 5% BCN/MnO2 was confirmed and characterized by various spectral techniques like Powder X-ray diffraction studies (XRD), Fourier transform infrared spectroscopy (FT-IR), Transmission electron microscopy (HR-TEM), and electrical properties were also studied. The photocatalytic activity of 5% BCN/MnO2 nanocomposite was act as an efficient photocatalyst towards the degradation of Rhodamine B. The obtained result also confirms that the 5% BCN/MnO2 nanocomposites exhibit the better degradation irradiated in visible light compare to pristine MnO2 and CN.

Hydrothermal control of the lithium-rich Li2MnO3 phase in lithium manganese oxide nanocomposites and their application as precursors for lithium adsorbents.

Lithium manganese oxides (LMOs) are key materials due to their role in Li-ion batteries and lithium recovery from aqueous lithium resources. In the present work, we investigated the effect of the crystallization temperature on the formation by hydrothermal synthesis of LMO nanocomposites with high Li/Mn ratios. It is demonstrated that LMOs with a high Li/Mn ratio can be formed by systematically favoring the lithium-rich layered monoclinic phase (Li2MnO3) in a mixture of monoclinic and spinel crystalline phases. LMO nanocomposites have been characterized in terms of morphology, size, crystallinity, chemical composition and surface properties. Moreover, lithium adsorption experiments were conducted using acid-treated LMOs (HMOs) to evaluate the functionality of the nanocomposites as lithium adsorbent materials in a LiCl buffer solution. This study spotlights the structural, compositional, and functional properties of different LMO nanocomposites obtained by the hydrothermal method using the same Li and Mn precursor compounds at slightly different crystallization temperatures. According to our knowledge, this is the first report of the successful application of the lithium-rich Li2MnO3 phase in lithium manganese oxide nanocomposites as lithium adsorbent materials. Therefore, specific LMO nanocomposites with controlled amounts of the layered phase can be engineered to optimize lithium recovery from aqueous lithium resources.

Synthesis of lithium manganese oxide nanocomposites using microwave‐assisted chemical precipitation technique and their performance evaluation in lithium‐ion batteries

AbstractLithium manganese oxide (LMO), carbon nanotubes (CNTs), and graphene nanoplatelets (GNPs) were used to develop nanocomposites using a microwave‐assisted chemical precipitation method and characterized using various techniques. The process provides better control over morphological features and proficient choice of cost‐effective precursors. This research aims to increase the active surface area and the number of lithium‐ion (Li+) intercalation sites using the CNTs and GNPs in LMO to improve its electrochemical performance. The structural analysis shows that the average crystallite size is 50 nm without using any capping agent during the synthesis process, which is smaller when compared to pristine LMO. The electrochemical studies demonstrate that the incorporation of carbon nanostructures (CNTs and GNPs) boosts the rate capabilities and cyclic performance of LMO. The LMO‐CNTs and LMO‐GNPs have an excellent rate capability of 124 and 127 mAhg−1 at 0.1C, sustained at 115.6 and 118.5 mAhg−1 at 10C, respectively. Cycling efficiency is also improved, with LMO‐CNTs and LMO‐GNPs having an initial capacity of 124 and 127 mAhg−1 decreasing to 112 and 114 mAhg−1, respectively, after 50 cycles. Compared to pure LMO, the increased electrochemical performance of LMO nanocomposites is due to the introduction of carbon nanostructures (CNTs and GNPs).

Fungus Bran-Derived Porous N-Doped Carbon–Zinc Manganese Oxide Nanocomposite Positive Electrodes toward High-Performance Asymmetric Supercapacitors

The common forest waste fungus bran (FB) having the advantages of sustainability, abundance, and availability was used to produce carbon products or carbon matrix hosting composites. The existing abundant nitrogen in FB served as a dopant to in situ dope the formed carbon skeleton. The FB-derived N-doped carbon product was porous (named FPC) and displayed flake structures. Its specific surface area was up to 1515 m2 g–1 and had a suitable pore size distribution. This FPC electrode showed a promising capacity of 380 F g–1 at a current density of 1 A g–1. The composite was fabricated using FPC as a template to in situ form the zinc manganese oxide (ZMO) nanocubes at different ratios (the composites are denoted FPZM), and the corresponding as-prepared composites (with an FPC-to-ZMO ratio of 1:3) electrode displayed a higher charge capacitance of 537 F g–1 at 1 A g–1 and favorable cycle performance. The energy density of an asymmetric device with composite electrode as the positive electrode and FPC as the negative electrode was 13.54 Wh kg–1 at 700.34 W kg–1. The synergistic effect between the biomass-derived carbon and pseudocapacitive oxides gave an improved energy-storage performance. Our experimental results show that the forest waste can be effectively utilized as an activated carbon material for wide applications.

Graphene Foam (GF)/Manganese Oxide (MnO2) Nanocomposites for High Performance Supercapacitors

Abstract We report supercapacitive characteristics of hierarchically porous architectured graphene foam (GF)/manganese oxide (MnO2) nanocomposites fabricated via a simple two-step synthesis route. A polyurethane (PU) foam with graphene flakes adsorbed onto the pore walls is pyrolyzed to obtain GF. The MnO2 is then electrochemically deposited onto GF to form a GF/MnO2 (with a conductivity of 2.85 and 1.1 Sm−1, respectively) nanocomposite. The GF is an ideal scaffold template for electrochemical deposition of MnO2 and fast ion transport from MnO2 to GF. The GF/MnO2 supercapacitor shows excellent specific capacitance (672 F g−1), rate capability (85% capacity retention over 1 to 20 A g−1), and long cycle life (2% capacity loss after 10000 charge/discharge cycles) for 0.5 mg cm−2 MnO2 loading. Furthermore, the optimized supercapacitor delivers a specific energy of 95 Wh kg−1 at a specific power of 1 kW kg−1, which is substantially higher than that of most of the reported GF based supercapacitors. The results obtained here may pave the way for the development of commercial supercapacitors for future energy storage systems.

PREPARATION AND STRUCTURAL CHARACTERIZATION OF MoS2 NANOPARTICLE COATED GRAPHENE OXIDE/MANGANESE OXIDE COMPOSITE FOR ENERGY STORAGE APPLICATION

Nanoparticles of powder molybdenum sulphide (MoS2) are deposited on reduced graphene oxide-mesoporous manganese oxide nanocomposite which is represented as MoSGMn were prepared by feasible ultrasonic assisted deposition technique. The above prepared nanocomposite is further coated on Nickel foam substrate for direct application towards supercapacitor electrode fabrication. The detailed studies of thermal property and surface property such as thermal stability, surface structure and zeta potential measurements have been explained for all prepared nanocomposite samples. The thermal stability of as prepared sample stable upto 350 oC in oxygen atmosphere and negative zeta potential obtained for all prepared nanocomposite sample. The different amount of MoS2 nanoparticle (10mg -100 mg range) was utilized to study the effect of molybdenum sulphide addition on major mesoporous manganese oxide matrix. Increased quantity of MoS2 addition increase the electrochemical supercapacitance value of the nanocomposite coated nickel foam modified electrode.

Surface bound nanostructures of ternary r-GO / Mn3O4/V2O5 system for room temperature selectivity of hydrogen gas

Room temperature detection of highly sensitive Hydrogen (H2) gas sensing material preparation was taken as a major objective in this present work. Herein, a novel one pot hydrothermal method is proposed for the synthesis of ternary r-GO decorated Manganese oxide (Mn3O4) and Vanadium pentoxide (V2O5) nanocomposite. The significant electrical conductivity of r-GO plays an important role here to enhance the sensing property. Tunable band bending features of metal oxides over the r-GO surface makes the composite works at room temperature with high selectivity of H2. The optical, structural and morphological characteristics were analyzed by UV–Visible spectroscopy (UV–Vis), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray Photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), and High Resolution-Transmission Electron Microscope (HR-TEM). The sensing results reveals that the present nanocomposite is selectively sensitive towards H2 with sensitivity value of (175%) at room temperature with response time (82 s) and recovery time (92 s). To investigate the low detection limit gas concentration was varied in the range from 20 ppm to 50 ppm. The synergetic sensing performance and stability of this nanocomposite could be due to the formation of metal oxides with perspicuous nanostructures as heterojunction decorated over the r-GO stack layer.

Intelligent Protein-Coated Bismuth Sulfide and Manganese Oxide Nanocomposites by Biomineralization for Multimodal Imaging-Guided Enhanced Tumor Therapy

Radiotherapy (RT) has been used clinically to overcome cancer in recent decades. However, the abnormal tumor microenvironment (TME) featured with hypoxia, acidosis, and dense extracellular matrix is found to be related with the resistance of tumors to RT. Herein, intelligent bovine serum albumin (BSA)-coated Bi2S3 and MnO2 (Bi2S3-MnO2) nanocomposites synthesized by biomineralization are capable of modulating hypoxic TME effectively to enhance the efficacy of RT. After intravenous injection, the BSA-Bi2S3-MnO2 nanocomposites show efficient accumulation in tumor where endogenous H2O2 could be reacted with MnO2 to generate oxygen in-situ, leading to increased tumor oxygenation to overcome the hypoxia-associated resistance for RT. Moreover, the photothermal effect induced by BSA-Bi2S3-MnO2 nanocomposites further relieves the hypoxia in TME and finally synergistically improves RT effect. In this work, we present a simple strategy to fabricate intelligent therapeutic nanoparticles for improving therapeutic efficiency in cervical cancer.