Synthesis Of Manganese Oxide Nanoparticles Research Articles

A facile green synthesis of manganese oxide nanoparticles using gum karaya polymer as a bioreductant for efficient photocatalytic degradation of organic dyes and antibacterial activity

The release of organic dyes into water systems, mainly textile industries, poses a significant threat to human and animal health. This approach shows great potential for effectively removing harmful dyes and microorganisms from wastewater treatment for environmental remediation. This study utilized gum karaya polymer bio-reductant to synthesize manganese oxide (MnO2) nanoparticles through a green approach. The synthesized MnO2 nanoparticles were characterized and confirmed by various analytical techniques. These results revealed their nanoscale dimensions, morphology, chemical purity, crystal nature, decolorized intermediate, and band gap. The photocatalytic degradation of hazardous Congo red and methyl orange dyes using KRG-MnO2 nanoparticles under visible light irradiation. Furthermore, the results demonstrated that Congo red dye degradation efficiency of 93.34 % was achieved. The dye concentration (8 to 16 mg/L), pH concentration, and radical trapping were studied. This suggests that holes and hydroxyl radicals play a crucial role in degrading the Congo red dye and demonstrate superior recyclability after three successive cycles and good stability. The possible intermediates from the Congo red dye degradation were identified through LC-MS analysis. The polymer composite MnO2 NPs have displayed notable antibacterial activity against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. The research indicates that MnO2 nanoparticles functionalized with polymers can efficiently remove pathogens and organic dyes from diverse industrial water treatment processes.

Synthesis and phase transformation study of nanostructured manganese oxide polymorphs

This paper presents the green synthesis of manganese oxide nanoparticles using olive leaf extract (OLE). The extract functions as both a reducing agent, responsible for converting manganese ions into nanoparticles, and a capping agent, aiding in stabilizing the formed nanoparticles. Our focus lies on investigating the thermal stability, phase transformation, and decomposition temperatures of different manganese oxide phases in powder form as a function of the calcination temperature. Since phase transformation depends on temperatures change at the nanoscale both thermogravimetric and differential scanning calorimetry (TGA, DSC) are used to determine the new phase transformation temperatures of the synthesized nanoparticles. Moreover, the phase structure and the exact stoichiometry are studied using ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning/transmission electron microscopy (SEM/TEM). XRD and XPS analyses reveal the formation of amorphous MnOx at room temperature (prior to calcination), transitioning to crystalline phases (Mn2O3 and Mn3O4) post-calcination. High-resolution TEM and SEM depict the formation of nanoparticles around 15 nm in size, exhibiting different shapes. BET technique calculations give a very high specific surface area, rending these nanoparticles excellent candidates for several applications.

Biological synthesis of manganese oxide nanoparticles from aerial parts of Prunus dulcis and their in vitro investigation of medical properties

The field of functional nanohybrid material is an emerging research area in material science due to its vast range of applications. The use of novel technology and innovative therapeutics has led to potent applications, including controlling the size of nanoparticles (NPs). This has resulted in a novel report on the synthesis of manganese oxide NPs using aerial parts of queen of roses Prunus dulcis (almond) leaves, seed, and seed oil (using Clevenger apparatus), which functions as a reducing agent. Manganese sulfate was used as a precursor in the synthesis process. The synthesized nanohybrid Mn3O4 NPs were studied using different characteristics techniques such as X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy‐dispersive X‐ray spectroscopy (EDX). The photoluminescence spectra display the blue emission ranging from 483.2 to 486.5 nm. The biosynthesized Mn3O4 NPs were tested for bactericidal activity and showed tremendous inhibition against gram‐positive and gram‐negative bacteria. The antioxidant activity of Mn3O4 NPs was enhanced using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay, which revealed the higher activity of Mn3O4 NPs from P. dulcis leaf extract. In vitro cytotoxicity of hybrid Mn3O4 NPs was examined using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay against cervical cancer (HeLa cell line) with different concentrations. The results showed an IC50 value of 61.97 μg mL−1 for Mn3O4 NPs from P. dulcis leaf extract. In general, the phytosynthetic route with synergistic effect of nanohybrid demonstrated an interaction with cancer cells, highlighting a pioneering optimum approach in synthesis of Mn3O4 NPs from aerial parts of P. dulcis.

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.

Ficus-mediated green synthesis of manganese oxide nanoparticles for adsorptive removal of malachite green from surface water

The extract of ficus leaves was used to prepare manganese (IV) oxide nanoparticles (MnO2 NPs) for the first time. Several different analytical techniques were used to characterize the prepared MnO2 NPs. MnO2 has spherical crystals that are ~ 7 nm on average in size and have 149.68 m2/g of surface area and 0.91 cm3/g of total pore volume. Malachite green (MG) dye was then taken out of the water by adsorption using MnO2 NPs. Optimization of various adsorption parameters resulted in 188.68–277.78 mg/g maximum adsorption capacities at 298–328 K tested temperatures and 99.6% removal of 50 mg/L MG within 90 min using MnO2 dose of 0.01 g at pH 10 and 298 K. The results were tested using pseudo-first order, pseudo-second order, intraparticle diffusion, Elovich, and Liquid film kinetic models as well as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models. The most likely models to describe the adsorption process at 298 K are pseudo-second-order kinetics (R2 = 0.997) with a rate constant of 4 × 10−4 g/(mg.min) and Langmuir isotherm (R2 = 0.973). Additionally, the positive values of enthalpy change (3.91–67.81 kJ/mol) and the negative values of Gibb’s free energy (− 3.38 to − 19.7 kJ/mol) indicate that the process is endothermic, spontaneous, and thermodynamically feasible. MnO2 NPs sustained their adsorption efficiency at 90.4% after 5 sorption cycles. MnO2 appears to be more selective for MG in studies examining the adsorption of various cationic dyes. Lately, the biosynthesized MnO2 NPs can be utilized to remove MG from aqueous solutions effectively.

Detailed Analysis of Crystal Structure and Optical Properties of Green Synthesized Nanoparticles: Application for Photocatalyst Degradation of Methylene Blue

We report the green chemistry reduction approach method for the synthesis of Manganese Oxide nanoparticles (MnO NPs), Copper Oxide nanoparticles (CuO NPs) and Manganese-doped Copper Oxide nanoparticles (Mn-doped CuO Nps). Aqueous extract from the seeds was used as reducing and capping agents. The detailed crystal structure analysis was investigated; crystallite size, crystallinity, morphological index, x-ray density, bulk density, specific surface area, porosity, Lorentz factor, Lorentz polarization factor and other parameters were calculated. Simple EDX mapping reveals the presence of Mn, Cu, O and C. FTIR analysis was used to determine the bond length of a nanocomposite. In the visible area, nanoparticles have higher optical absorption, with bandgaps varying from 1.79 (MnO), 2.18 eV (CuO) and 1.72 eV (Mn-doped CuO). After 90 min, the photodegradation rate of Mn-doped CuO nanocatalysts was 93.73 % while using a smaller amount of catalyst (0.1 g) at pH 7. The pseudo-first-order MB photocatalytic decomposition kinetic model has a high correlation coefficient value (R2 > 0.95). It was found that Mn-doped CuO NPs have higher photocatalytic efficiency and can be used as potential photocatalysts for industrial dye degradation. HIGHLIGHTS Green synthesis of Mn, Cu, and Mn-doped Cu nanoparticles by Bambusa seeds extract Characterized via XRD (crystal structure), UV-Vis Diffuse Reflectance spectra (UV-DRS), FT-IR (bond length), and FESEM-EDS analysis Photocatalytic degradation of organic methylene blue dye using Mn-doped CuO nanoparticles GRAPHICAL ABSTRACT

Eco-Friendly Synthesis of MnO2 Nanorods Using Gmelina arborea Fruit Extract and Its Anticancer Potency Against MCF-7 Breast Cancer Cell Line.

IntroductionCancer disease is known due to its unregulated proliferation of cells that have evolved from the body’s regular cells. The disease develops as a result of epigenetic and genetic modifications, tumor suppressor gene inactivation, and oncogene activation. The present work describes an environmentally benign approach for the synthesis of manganese oxide nanoparticles (MnO2 NPs) using Gmelina arborea fruit extract (GAE) in an aqueous medium.MethodsThe study evaluated the formation of MnO2 NPs and their anticancer efficacy against MCF-7 breast cancer cell line.ResultsThe formation of MnO2 NPs was confirmed through powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM). The crystalline nature of as-prepared MnO2 NPs was evident from XRD pattern. The morphology of the material was studied using SEM analysis, which suggested a rod-like nature with an average diameter of 50 nm. Further, the TEM and HR-TEM images confirmed the rod shape of the as-prepared MnO2 NPs with an interplanar distance of 0.271 nm. In addition, the concentric rings from selected area electron diffraction (SAED) analysis show the crystalline nature of the as-prepared material, which further supports the obtained XRD pattern. The anticancer efficacy of MnO2 NPs was evaluated against MCF-7 breast cancer cell line, which showed up to 96% inhibition of the cells at 400 µg/mL concentration.ConclusionBio-conjugation of MnO2 NPs can provide enough scope for the therapeutic use of Gmelina arborea, assuming appropriate mechanistic evaluations are conducted.

Effect of calcination temperature on morphology and phase transformation of MnO2 nanoparticles: A step towards green synthesis for reactive dye adsorption

Green synthesis of manganese oxide nanoparticles (NPs) was carried out by sol-gel method using Acacia Concinna fruit extract for removal of reactive dye. The effect of calcination temperature on its morphology was investigated. α-MnO2 and Mn3O4 NPs were synthesized at 400 °C and 900 °C respectively and were characterized by PXRD, SEM, TEM, FTIR, BET, Raman and TGA. As-synthesized MnO2 NPs were investigated for the adsorption of Reactive Blue 21 (RB-21) dye. The effect of pH, adsorbent dose, agitation speed, initial dye concentration and temperature on dye removal was explored. pHpzc was calculated from zeta potential study showing positive surface charge below pH 3.18 resulting in electrostatic force of attraction between adsorbate and adsorbent. Both linear and non-linear regression approaches were utilised for the fitting of kinetic models and adsorption isotherms. Adsorption data follows a pseudo second order kinetics and fits well with the Freundlich isotherm model. Thermodynamic parameters such as ΔHo, ΔSo and ΔGo were determined. The dye removal efficiency, in case of MnO2 NPs at pH 3.0 was obtained to be 98% whereas for Mn3O4, no such dye adsorption was observed. The mechanism of adsorption was studied theoretically confirming π-π interaction and H-bonding between the MnO2 and RB dye molecules.

Antibacterial Activity, Characterizations, and Biological Synthesis of Manganese Oxide Nanoparticles using the Extract of Aloe vera

Green nanotechnology is relatively new branch of science and technology with many interesting applications. This technology involves in the synthesis of inorganic nanoparticles (NPs) through green synthesis using extracts of plant-derived materials. Green synthesis of metal and metal oxide NPs is a good alternative over the other conventional physical and chemical methods. This study deals with the green synthesis of manganese oxide (MnO2) NPs using the extract of Aloe vera. The green synthesized MnO2 NPs have been synthesized using various analytical methods such as Fourier transform infrared, X-ray diffraction, and field emission scanning electron microscope. MnO2 NPs were tested for antibacterial activities against Escherichia coli, Streptococcus mutans, and Staphylococcus aureus using well diffusion method. The experimental results were indicating that the MnO2 NPs are good antibacterial agents against different bacterial species.

Hyperthermia Effect on Phantom of Breast Carcinoma Tissue Induced by Mn<sub>3</sub>O<sub>4</sub> Nanoparticles Synthesized by One-Step Spray Pyrolysis Method

In this work, the synthesis of manganese oxide nanoparticles was achieved by one-step spray pyrolysis method. The nanoparticles were synthesized just from MnCl2 aqueous solution. The solution was nebulized to a Si substrate placed at 400 °C for 1, 5 10 and 20 min and transported at a 0.1 L /min rate in a Nitrogen flux. The X-ray diffraction confirms tetragonal Mn3O4 as the unique phase in the whole sample. The scanning electron microscopy images proved the achievement of irregular nanoparticles with an average diameter of 280 nm experimentally determined by dynamic light scattering. Energy dispersive X-ray and Raman spectroscopy confirmed that the nanoparticles were obtained with Mn3O4 single-phase and the employed methodology prevented any contamination. The nanoparticles proved to induce temperature enhancement on artificial breast tissue by exposition to microwave radiation by achieving an increase in temperature around 8 %.

Green Synthesis of Manganese Oxide Nanoparticles from Cassia tora Leaves and its Toxicological Evaluation

Green Synthesis of Manganese Oxide Nanoparticles from Cassia tora Leaves and its Toxicological Evaluation

Methylamine Treated Mn3O4 Nanoparticles for Efficient Water Oxidation Catalyst at Neutral Condition

Developing alternatives to replace fossil fuels is an important issue for maintaining sustainable energy system in the future. Hydrogen fuel is an attractive alternative owing to its high energy density and environmentally friendly by-products. Electrical water splitting powered by a renewable energy source is a promising way to produce hydrogen fuel. However, anodic water oxidation is considered to be a bottleneck due to its high overpotential. Therefore, designing efficient catalyst for water splitting is regarded as an important issue. Previously, Ir and Ru-based catalysts have been shown to exhibit remarkable catalytic activity toward oxygen evolving reaction (OER) under acidic condition. Despite their high activity, it is difficult to use noble-metal-based catalysts for commercial applications because of the scarcity of precious metals and their costs. Therefore, non-precious transition metal oxide electrocatalysts were investigated for water oxidation reaction such as cobalt oxides, nickel oxides, iron oxides and manganese oxides.1,2 Their activities were only retained under basic conditions and advancement in electrocatalysts that show moderate activity at neutral pH has been relatively insufficient. Nature has highly efficient OER catalysts in photosystem II which is Mn4CaO5 cluster also called as oxygen evolving complex. Inspired by unique structure and catalytic mechanism of this cluster, Mn-based catalysts have been actively studied. Among various manganese oxide, nanoparticle system showed superior catalytic activity due to its totally different reaction mechanism compared to the bulk counterparts.3,4 However, after synthesis of manganese oxide nanoparticles, long alkyl organic ligands are attached on the surface of nanoparticles interrupting the approach of water molecules, which inhibits water oxidation. Previously, hydrophobic organic ligands were removed by thermal decomposition with sufficient annealing process. Alternative way to remove alkyl ligands is replacing it with different ligands through surface ligand treatment such as BF4 -, PF6 -, OH-, thiol, SCN- and PbCl3 -. Surface ligand exchange is beneficial in that it does not need high temperature annealing and possibility of fine surface control. We have successfully synthesized 6 nm Mn3O4 nanoparticles (NPs) and used for further surface treatments. Mn3O4 NPs were OH ligand exchanged as a first step and followed by methylamine treatment in aqueous solution. Identical TEM images and XRD patterns showed that the size of NPs was unchanged and the phase of NPs was maintained as Mn3O4. Electrokinetic study of the OER was analyzed by cyclic voltammetry (CV) at pH 7 and compared between OH ligand exchanged Mn3O4 NPs and further methylamine treated Mn3O4 NPs. Methylamine treatment reduced the overpotential for OER by nearly 100 mV at the current density 5 mA cm-2. Tafel slopes was also decreased after methylamine treatment to 83.1 mV dec-1. To understand the phenomenon of increased catalytic activity after methylamine treatment, further analysis of the surface of NPs were conducted using spectroscopic measurement. In the XPS O 1s spectra, surface hydroxyl group (Mn-OH) was increased up to 57.3 % after OH ligand exchange. Also, FTIR spectra showed increased ratio of Mn-OH to lattice oxygen (Mn-O-Mn) for OH ligand exchanged Mn3O4 NPs compared to Mn3O4 NPs which indicates successful OH ligand exchange on the surface of Mn3O4 NPs. After methylamine treatment of OH ligand exchanged Mn3O4 NPs, methylamine was not attached to the surface of NPs. XPS N 1s spectra did not show characteristic methylamine peak, FTIR did not show C-N vibration mode and elemental analysis indicates that N does not exist in the NPs. To figure out the role of methylamine on the surface of OH ligand exchanged Mn3O4 NPs, titration and zeta potential was measured. After methylamine treatment surface was more deprotonated. Deprotonation resulted in loss of positively charged proton which induced negative charge on the surface of Mn3O4 NPs and showed negative zeta potential. On the basis of nonexistence of methylamine on the surface and surface deprotonation after methylamine treatment, we hypothesized that methylamine work as Brønsted-Lowry base. Methylamine was replaced by ethylamine, ethylenediamine, dimethylamine, trimethylamine and ammonia water, then after reaction with different amines, overpotential was decreased for all cases. Interestingly, amines with larger pK a showed larger decrease in overpotential. Based on these results, we first proposed correlation between the surface charge and oxygen evolving activity. Deprotonating the surface of the catalyst through simple acid-base reaction induced a change in the surface state followed by catalytic activity improvement. This understanding can be applied for developing efficient nano-catalysts by deprotonating the nanoparticle surface to induce surface state change. [1] J. Am. Chem. Soc., 2014, 136, 4201-4211 [2] J. Am. Chem. Soc., 2014, 136, 7435-7443 [3] Sci. Rep., 2015, 5, 10279 [4] J. Am. Chem. Soc., 2017, 139, 2277-2285 Figure 1

Graphene Supported Manganese (IV) Oxide Nanoparticles As High-Performance Electrochemical Capacitor

The search for cleaner energy sources is required to shift focus to the generation of energy from electrochemical systems, batteries and fuel cells, solar cells, and super capacitors, among others. We report a simple one-step approach for microwave-assisted synthesis of manganese oxide nanoparticles deposited on the graphene (MnO2/GR) or carbon (MnO2/C) supports. The MnO2/GR and MnO2/C nanocomposites have been synthesized with different morphologies. The MnO2 nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical performance of the MnO2/GR and MnO2/C nanocomposites was evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge. It was found that the graphene supported MnO2 nanoparticles has significant influence on the electrochemical performance of composites electrodes compared with that of the carbon supported MnO2 nanoparticles. The maximum specific capacitance of 108 F g-1 was achieved at the MnO2/GR electrode in the 1 M Na2SO4 aqueous solution at the scan rate of 10 mV s-1. Acknowledgement This research is funded by the European Social Fund under the No. 09.3.3-LMT-K-712-02-0142 “Development of Competences of Scientists, other Researchers and Students through Practical Research Activities” measure.

Optimisation of green synthesis of MnO nanoparticles via utilising response surface methodology.

This study concerns the optimisation of green synthesis of manganese oxide nanoparticles (MnO NPs) with Dittrichia graveolens (L.) extract via response surface methodology (RSM). Central composite design was used to evaluate the effect of pH, time, and the extract to the metal ratio on the synthesised nanoparticles (NPs). Nine runs were designed to investigate the effect of each parameter while NPs were synthesised under different conditions. Considering the p-values (p-value < 0.05), it is indicated that the extract to the metal ratio was the most effective parameter. The synthesised NPs were characterised using UV-vis. Synthesis of the NPs by polyphenolic compounds of green reducing agent and their stabilisation by curcumin was confirmed by Fourier transform infrared spectra and the surface morphology of the spherical MnO NPs was studied by field-emission scanning electron microscopy and transmission electron microscope techniques. The present researchers claimed the optimal condition as follows: time = 56.7 min, pH = 7.2, and the extract to the metal ratio = 87.9 v/v. MnO NPs at optimum condition were then employed for degradation of industrial dyes and they showed high dye degradation activity against Rhodamine B and light green dye. The average size of the synthesised MnO NPs at optimal condition was claimed to be nearly 38 nm.

Self-catalyzed surface grafting of Mn3O4 nanoparticles with polylactide and its magnetic properties

Magnetic properties of nanoparticles are size dependent and surface grafting of nanoparticles not only prevents their agglomeration but can also lead to effective domains separation. Present study deals with the synthesis of manganese oxide nanoparticles (< 5 nm) by microwave assisted solvothermal process and its grafting with poly L-lactic acid by a self-catalyzed ring opening polymerization of L-lactide. The Mn3O4 nanoparticles and Mn3O4/PLLA nanocomposite were characterized by many analytical techniques such as FT-IR, TEM, 1H NMR, 13C NMR, XRD, XPS, TGA and DSC etc. The magnetic properties of nanoparticles and nanocomposites were studied using VSM and SQUID showed marked shift in magnetic behavior of Mn3O4 nanoparticles which were super paramagnetic, on coating with PLLA.

Permanganate-based synthesis of manganese oxide nanoparticles in ferritin

This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin.

Green synthesis of manganese oxide nanoparticles for the electrochemical sensing of p-nitrophenol

Manganese oxide (MnO) NPs are widely used in contaminant sensing, drug delivery, data storage, catalysis and biomedical imaging. Green synthesis of NPs is important due to increased concern of environmental pollution. Green chemistry based synthesis of NPs is preferred due to its ecofriendly nature. In this study, MnO NPs of different sizes were synthesized in aqueous medium using clove, i.e., Syzygium aromaticum extract (CE) as reducing and stabilizing agents. These NPs were used for the electrochemical sensing of p-nitrophenol (PNP). The synthesis of MnO NPs was over in 30 min. MnO NPs of different sizes were obtained by varying metal ion concentration, metal ion volume ratio, CE concentration, CE volume ratio, and incubation temperature. Selectively, ~4 nm MnO NPs were used for electrochemical sensing of paranitrophenol. The MnO NPs modified gold electrodes detected PNP with good sensitivity, 0.16 µA µM−1 cm2. The limit of PNP detection was 15.65 µM. The MnO NPs prepared using CE based green chemistry approach is useful for PNP sensing. These NPs can also be useful for various in vivo applications in which the NPs come in human contact.

Formation of octapod MnO nanoparticles with enhanced magnetic properties through kinetically-controlled thermal decomposition of polynuclear manganese complexes

Polynuclear manganese complexes are used as precursors for the synthesis of manganese oxide nanoparticles (MnO NPs). Altering the thermal decomposition conditions can shift the nanoparticle product from spherical, thermodynamically-driven NPs to unusual, kinetically-controlled octapod structures. The resulting increased surface area profoundly alters the NP's surface-dependent magnetism and may have applications in nanomedicine.

Reactivity of poly(dimethylsiloxane) toward acidic permanganate

Poly(dimethylsiloxane) (PDMS) has been widely used in various microfluidic devices because it is considered to be one of the most inert materials available. A PDMS-based microfluidic system for the synthesis of manganese oxide (MO) nanoparticles is developed and tested. However, synthesis of MO nanoparticles in the PDMS-based microfluidic system is unsuccessful due to an unexpected reaction between acidic permanganate and PDMS. PDMS is pitted and coated with MnO2 and opalized silica, which are confirmed by SEM and EDX. The products of the reaction between PDMS and acidic permanganate are mainly MnO2, Cl2, SiO2 and CO2, respectively. Here we report for the first time the reactivity of PDMS toward acidic permangante resulting in a new process to coat the channel walls with MnO2.

A Novel Rapid One-Step Synthesis of Manganese Oxide Nanoparticles at Room Temperature Using Poly(dimethylsiloxane)

We report for the first time a novel rapid synthesis method for manganese oxide (MO) nanoparticles by a reaction between acidic permanganate and poly(dimethylsiloxane) (PDMS). In contrast to the existing traditional methods for synthesis of MO nanoparticles, the new method has the advantage of shorter reaction time (∼2 h) at room temperature (∼25 °C). The produced MO nanoparticles are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM, HRTEM). The material produced is semicrystalline silicon-doped MnO2 with homogeneous size and morphology with an average particle size around 300 nm. Other products of the reactions include Cl2, silicon dioxide sheets on PDMS, and CO2. A mechanism for this reaction is proposed. The prepared MO was successfully used as a catalyst for the rapid and highly efficient degradation of a water pollutant—Rhodamine B (RhB).