Type Manganese Research Articles

Reduced lattice spacing of birnessite type manganese dioxide/ expanded graphite cathode for stable aqueous zinc-ion batteries

Manganese oxides (MnOx) have attracted much attention due to abundant resource, low cost and eco-friendliness. In this study, birnessite type manganese dioxide/expanded graphite composites (KMO/EG) with a reduced lattice spacing of nanoflower and nanowire heterostructure KMO have been synthesized by a one-step hydrothermal method. The morphology of KMO has transformed from nanoflower to nanowire with a reduced lattice spacing due to nucleation sites on the surface of EG. The KMO/EG achieves a specific capacity of 444.5mAh g−1 and remains at 387.9mAh g−1 after 100 cycles at 0.1 A g −1 for Zn-ion battery. The enhanced specific capacity of KMO/EG is mainly attributed to the capacity contribution of EG and the good stability is related to the more stable structure of KMO caused by reduced lattice spacing.

SnO2/MnOx composite systems as VOCs sensors: Influence of manganese chemical state and distribution on functional performances

SnO2/MnOx nanocomposites with manganese content up to [Mn]/([Mn]+[Sn]) = 10 mol.% were prepared using chemical precipitation and impregnation-annealing techniques and examined using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, mass-spectrometry with inductive coupled plasma. Manganese distribution between the bulk and the surface of SnO2 crystal grains depending on the total manganese concentration was determined and the chemical state of both type (bulk and surface) manganese cations was identified. Strong correlations of sensor signal toward C1 volatile organic compounds (methanol, formaldehyde, formic acid) and C1–C4 carbonic acids (formic, acetic, propionic, butyric) with the total manganese content, manganese distribution and chemical state were revealed.

Self-assembled from monometallic-organic framework to bimetallic-organic framework materials with promoted supercapacitor performance

Designing new metal–organic frameworks (MOFs) materials with definite structure and introducing heterometallic atom is an effective strategy to develop new electrocatalytic and energy storage materials. Herein, one new 3D close-packed type manganese metal–organic frameworks, namely [Mn2(BPTC)(DMSO)2.5] (Mn-MOF) have been constructed from a rigid biphenylic acid with a rigid biphenyl-3,3′,5,5′-tetracarboxylic acid (H4BPTC) ligand under a solvothermal condition. Besides, adopting the metal doping strategy, a series of bimetallic MnM’-MOF (M’=Co, Ni and Cu) crystalline materials has been successfully grown on nickel foam (NF) and were used for supercapacitor electrode material. By contrast, the MnNi-MOF/NF shows a specific capacitance of 3391.7 mF cm−2 at 1 mA‧cm−2 in 1.0 M KOH, which is 1.6 times that of Mn-MOF/NF electrode. It also displays excellent cycle stability to keep 92.6 % of the initial capacity after GCD 20000 cycles. Finally, a hybrid supercapacitor (HSC) made from on the MnNi-MOF electrode and activated carbon (AC) could deliver an energy density of 0.224 mWh cm−2 at a power density of 1.04 mW cm−2, and a high cycle-to-cycle stability with 90.1 % of the primary capacitance over 20,000 cycles. This work not only confirms the potential supercapacitor properties of as-synthesized new Mn-MOF, but also effectively improves the specific capacity and device stability of pure Mn-MOF by introducing different transition metal ions.

Discovery of Late Carboniferous high-grade carbonate-hosted manganese mineralization in the Maerkansu area of the Western Kunlun Orogen, Northwest China

The Aoertuokanashi deposit located in the Western Kunlun Orogen is the first known Late Carboniferous large high-grade carbonate-hosted Mn deposit in the world and it has been mined since 2018. The deposit is considered to have formed in a back-arc basin developed during the northward subduction of the Paleo-Tethys Ocean beneath the Tarim Block. The Re-Os isotope isochron age of Mn ore at the Aoertuokanashi deposit is 302 ± 9 Ma. The minimum initial 187Os/188Os values obtained from the deposit is 0.28, which indicates the presence of a mantle source for the mineralization. The Aoertuokanashi deposit is similar in age to the 301 ± 5 Ma Wajilitag kimberlite in the Tarim Block, which is considered to be the initial magmatic pulse triggered by the Tarim mantle plume. The Late Carboniferous Aoertuokanashi Mn deposit was likely promoted by igneous activity from the Tarim mantle plume.The Aoertuokanashi deposit shows geochemical characteristics of hot water activity in a back-arc basin. The Mn mineralization is hosted in the restricted platform facies. Framboidal pyrite, typical biomat, and authigenic quartz are observed in the Mn deposit, indicating the influence of microbial processes. The sedimentary facies show a starving basin feature that can enhance microbial mediation. The δ13CV-PDB values of mineralized rocks (from −19.5 to −8.2 ‰) are more negative than those of wall rocks (from −5.3 to + 4.2 ‰), whereas the δ13CV-PDB values (around −29 ‰) of kerogen for the Mn ore are significantly lower than those of the whole rock. These compositions indicate that the reducing function of organic matter played an important role in Mn mineralization. In the inferred extensional tectonic environment, under the influence of a mantle plume, the stratum with strong hot water activities and a large amount of organic matter becomes the focal point for the formation of carbonate type manganese ore deposit.

Correlation of Serum levels of Chromium, Copper, and Manganese with the Glucose levels in Type 2 Diabetes Mellitus in Iraq

Correlation of Serum levels of Chromium, Copper, and Manganese with the Glucose levels in Type 2 Diabetes Mellitus in Ira Background: The metabolism of many trace elements such as chromium, copper, and manganese were reported to be altered in type 2 diabetes militates. This element may have specific roles in the pathogenesis and progress of this disease. Objectives: To evaluate the serum levels of copper, chromium, and manganese in type 2 diabetic patients in Iraq. Patients and Methods: This case-control study included 100 type 2 diabetic patients, 35-60 years old, with high BMI as cases, and 100 non-diabetic subjects as controls who were healthy volunteers not suffering from type 2 diabetes (staff and student). The data was collected from October 2022 until January 2023. The cases were seen in the Diabetes Consultation Unit / Baghdad Teaching Hospital / Medical City. Serum chromium, copper, and manganese were measured using atomic absorption. ELISA was used to test for insulin. spectrophotometry to measure glucose and HPLC was used to measure whole-blood HbA1c. Insulin resistance was calculated using the semi-empirical formula: HOMA-IR = glucose * insulin / 405 (glucose in mg/dl). To test for the difference between means of numerical data across several parameters, ANOVA tests were utilized. Pearson’s. correlation was used to test the correlation between variables. Results: Diabetics had higher HbA1c, serum copper (P value<0.01), and blood glucose than healthy controls. Compared to controls, diabetics had lower serum chromium (P value<0.01) and manganese (P value < 0.01). In diabetics, chromium and manganese are highly negatively correlated with insulin resistance. Copper levels increase with increasing insulin resistance. Insulin levels were greater in type 2 diabetics (18.6 ± 4.1mlU/L) than in the control (6.2 ± 1.3) (p <0.01). Conclusions: Serum copper was high while serum chromium and manganese were low in type 2 diabetics. that indicates that these elements may have a role in the occurrence and development of type 2 diabetes. Received: May, 2023 Accepted: Oct., 2023 Published: Jan., 2024

Influence of adding manganese chromium-layered double oxide on the optical, magnetic and dielectric properties of cobalt spinel ferrite nanoparticles

Hydrotalcite-like materials such as layered double oxides (LDOs) are promising materials for many technological applications. Linking the multilayer structure of LDOs with the exceptional optical, magnetic, and dielectric properties of spinel ferrites could result in advanced nanocomposites for photovoltaic, magneto-recording, and high-frequency applications. For that purpose, nanocomposites of type manganese chromium-layered double oxide/cobalt spinel ferrite, (MnCr)-LDOx/CoFe2O4 (x = 1, 3, and 5 wt%), were produced by the co-precipitation route. X-ray diffraction (XRD) analysis showed the successful incorporation of MnCr-LDO in CoFe2O4 lattice. After a 5 wt% addition of MnCr-LDO, the lattice parameter of pure CoFe2O4 increased from 8.3832 Å to 8.4136 Å, the crystallite size increased from 18.7 nm to 21.7 nm, and the strain dropped from 2.15 to 2.04. Transmission electron microscopy (TEM) revealed cubic morphologies for (MnCr)-LDOx/CoFe2O4 nanocomposites. Two strong absorbance peaks appeared in the Ultraviolet- visible (UV-vis) spectra (at ∼270 and ∼370 cm−1). The energy band gap and Urbach energy were estimated for the prepared samples. The composite sample (MnCr)-LDO1 wt%/CoFe2O4 recorded the highest band gap values (Eg1 = 3.39 eV, Eg2 = 4.46 eV, and Eg3 = 5.89 eV), while the (MnCr)-LDO3 wt%/CoFe2O4 sample had a relatively high Urbach energy value (1.35 eV). Vibrating sample magnetometer (VSM) analysis showed room temperature ferromagnetic (RTFM) behavior for the prepared composites. The saturation magnetization (Ms) value declined as the MnCr-LDO addition to CoFe2O4 increased, and the (MnCr)-LDO3 wt%/CoFe2O4 sample acquired the highest Ms (64.428 emu g−1) among all the produced composites. Pure CoFe2O4 had a much higher coercivity (Hc = 1158.1 Oe) than (MnCr)-LDOx/CoFe2O4 (x = 1, 3, and 5 wt%) nanocomposites (Hc = 1119.8, 978.48, and 984.16 Oe). Moreover, complex impedance spectroscopy measurements were performed in frequency range of 50 Hz- 5 MHz using Nyquist plots and electric modulus analysis. Nyquist plots were fitted to an analogous electric circuit consisting of a resistor R1 connected in series to two parallel constant phase element- resistor circuits (CPE-R). On the other hand, a different circuit comprises of two CPE, capacitor (C1), and resistor all connected in parallel was used to model CoFe2O4.

Structural and Electrochemical Investigation of 3D Tunnel Type Li0.44MnO2 Cathode Material for Secondary Li-Ion Batteries

The design of new cathode materials remains a key goal in the development of (post) Li-ion batteries. In that regard, densely packed structures like Li0.44MnO2 are judicious for study. The presence of Mn as a transition metal makes it more attractive due to its sustainable nature, low cost, elemental abundance, structural diversity/polymorphism, and rich oxidation states (2+ to 7+) offering tunable redox potential [1]. Here, we have investigated Mn-based tunnel-type Li0.44MnO2 oxide for secondary LIBs. i) Li44MnO2 (LMO) was prepared by a soft chemical method using the corresponding sodium manganese oxide (Na0.44MnO2) as a parent compound [2]. The crystal structure of Li0.44MnO2 maintains the parent Na0.44MnO2-type tunnel structure which is analogous to Na4Mn4Ti5O18 having an orthorhombic (s.g. Pbam) crystal system [3]. To understand redox chemistry, this material was studied for both cationic (Mn) and anionic (O) redox reactions using ex-situ X-ray photoelectron spectroscopy. The lithium (de)insertion mechanism of Li0.44MnO2 was explored involving ab initio calculations and in-situ X-ray diffraction experiments. Combined with electrochemical measurements, structural characterizations, and first principles DFT calculations revealed the capacity correlated strongly with both cationic and anionic redox reactions. ii) We have studied the phase transition of Li44MnO2 from a 3D tunnel-type structure to a cubic spinel structure by in-situ X-ray diffraction and Raman spectroscopy. The mechanism of transformation was elucidated by employing transmission electron microscopy. In this case, diffusion-less transformation occurs involving the rearrangement of atoms during heating [4]. An increase in the average redox potential from the pristine orthorhombic phase to the final spinel phase was observed by electrochemical studies. iii) Further to improve the electrochemical performance of Li0.44MnO2, Ti was used as a dopant. The Li0.44[Mn1-xTix]O2 (x=0, 0.11, 0.22, 0.33, 0.44, 0.56) series were obtained with chemical ion exchange from Na precursors. The Na precursors (Na0.44[Mn1-xTix]O2) were prepared via a simple solid-state route. Ti-substituted compositions exhibited similar crystal structures to their parent LMO i.e. orthorhombic framework with Pbam symmetry. A tunnel-type morphology was observed in all cases. The electrochemical performance of Ti-substituted LMO as cathode material for LIBs was studied in a half-cell configuration. The structure and electrochemical properties of Ti-doped LMO, reaching the highest capacity of 128 mAh/g, will be described. Keywords: batteries; cathode; tunnel type manganese oxides; phase transformation; doping

Vanadomanganate as a synergistic component in high-performance symmetric supercapacitor

Supercapacitor devices fabricated from capacitive and battery-type hybrid electrodes have been projected as a promising energy storage system because of their ability to produce high specific power and energy simultaneously. In this work, we have demonstrated a facile method of impregnation of faradaic type manganese (III) polyoxovanadate, [MnV14O40]−6 on the high surface area substrate of activated carbon (AC) as well as graphene oxide (GO). Materials and electrochemical characterizations data confirm the successful incorporation of capacitive and faradaic type manganese (III) polyoxovanadate into the nanohybrid electrode material. Furthermore, the synergic effect between the carbonaceous nanostructures (AC/GO) and redox-active oxometalate (MnV14) provides a better pathway for ion transport to the interface resulting in enhancement of the conductivity, diffusion ability of the nanohybrid. Moreover, the battery-type MnV14 clusters disperse in the micro/mesopores of AC, whereas the oxygen-containing functional groups in GO act as active sites for anchoring of MnV14 clusters. Thus, the surface modification with MnV14 clusters enhances the specific capacitance of nanohybrid with remarkable electrical and mechanical stability. The AC/MnV14 nanohybrid exhibits an enhanced specific capacitance of 547 F g−1 with specific energy and power of 76 Wh kg−1 and 1600 W kg−1, respectively, at 0.8 A g−1 current density. Additionally, GO/MnV14 shows a specific capacitance of 330 F g−1 with improved specific energy and power of 30 Wh kg−1 and 1276 W kg−1, respectively, at the same current density. Moreover, both the nanohybrids possess excellent cycle stability by retaining 92% (AC/MnV14) and 90.6% (GO/MnV14) of initial capacitance even after 5000 sweeping cycles.

Evaluation of Catalase and Manganese in Type 2 Diabetic Patients in University of Port Harcourt Teaching Hospital

This study was carried out to evaluate catalase and manganese in type 2 diabetes mellitus patients. A total of 40 subjects Were included in this study. This comprised of equal number of male and female subjects respectively. Enzyme linked immunosorbent assay (ELISA) method was used for this study. The result showed that there is a significant increase (P < 0.05) in the fasting blood sugar level of male diabetics (11.3±3.1) when compared with male non diabetics (4.0±0.4), and female diabetics (9.4±0.8) when compared with female non-diabetics (3.8±0.3). There is no significant increase (P<0.05) in the mean catalase value of male diabetics (77.3±137.7) when compared with male (256.3±207.6) and female non diabetics (225.1±233.9) But there is significant increase in female diabetics (27.8±14.7) when compared with controls (77.3±137.7) and female non diabetics (225.1±233.9).There is also significant decrease (P<0.05) in the mean Manganese value of male diabetics (0.5±0.6) when compared with male non diabetics (0.9±0.3) and female diabetic(0.2±0.1) when compared with female non-diabetics (0.3±0.1).The result shows that serum catalase level and manganese is decreased in diabetic patients. It is therefore suggested that type 2 diabetes patient should consume meals and supplement rich in catalase and manganese.

Pre-depositing PAC-birnessite cake layer on gravity driven ceramic membrane (GDCM) reactor for manganese removal: The significance of stable flux and biofilm

Water laden with dissolved manganese ions presents a challenge to water treatment processes and drinking water quality. To address manganese removal, a gravity driven ceramic membrane filtration system was developed; the membrane was pre-modified by depositing freshly formed birnessite type manganese oxide (MnOx) attached on powdered activated carbon (PAC) on the membrane. The result indicated that PAC-MnOx coupled with ceramic membrane rejection enabled the enrichment of manganese oxide bacterial (MnOB) (103 MPN/mL) on the membrane, facilitating biogenetic manganese formation. The dominant MnOB (i.e., Hyphomicrobium) was identified using microbial community analysis. Intermittent dosage of PAC-MnOx at start-up period was likely to generate a cake layer effectively contributing to autocatalytic oxidation; The flux stablised at 41 L/(m2·h) after only 15-d operation, and the permeate of manganese was 0.089 mg/L. After 30-d operation, laser scattering particle analyzer (LASP) revealed that the particles (70.9 μm) within biofilm of gravity driven ceramic membrane (GDCM) grew larger compared with those present initially (48.5 μm) due to the newly formed biogenic MnOx attached to the carrier PAC, indicated by Raman analysis and X-ray Diffraction (XRD) analysis. Mn(III) as the predominant valence in MnOx conferred its outstanding catalytic oxidative capacity, as evidenced by X-ray photoelectron spectroscopy (XPS) analysis. SEM-EDS mapping demonstrated that a uniform flower-like birnessite structure was formed on the PAC surface, facilitating the transformation of MnOx to newly-formed birnessite on the vicinity of GDCM. Taking advantage of PAC and birnessite, the gravity driven filtration system developed in this study is anticipated to be an effective water treatment technique, particularly suitable for small footprint decentralized water supply sanitation.

Insight Into the Role of Ceria on OMS-2 and OL Materials for Catalytic Degradation of Toluene

Catalytic oxidation is one of the most efficient approaches for industrial volatile organic compounds (VOCs) elimination. MnOx-based catalysts have attracted much attention due to their remarkable low-temperature catalytic activity. Here, octahedral layered birnessite-type manganese oxide (OL-1) with layer spacing of 7 Å and cryptomelane type manganese oxide (OMS-2) with tunneled pore diameter of 4.6 × 4.6 Å were synthesized by a reflux method. Following this, Ce-doped OL-1 and OMS-2 were further prepared by an impregnation method with target to improve catalytic performance in toluene oxidation. Results reveal that the OMS-2 material exhibits the best catalytic activity with 90% of toluene decomposed at 224 °C owing to the presence of a large quantity of active lattice oxygen species. Interestingly, the introduction of Ce leads to the formation of large amounts of acidic sites, which limit the oxidation process and enhance the yield of benzoic acid by-product. The findings in the present work are meaningful for deepening our understanding of the role of ceria on metal oxide catalysts and helping us to design effective catalysts for VOC destruction.

Fast synthesis of δ-MnO2 for a high-performance supercapacitor electrode

We report a very simple and fast route for a high capacitive birnessite type manganese dioxide (δ-MnO2) synthesis, fully suitable to be applied as electrode in redox-based electrochemical supercapacitors. The material was obtained from a very efficient chemical reduction of potassium permanganate by nascent hydrogen in low temperature acid media. δ-MnO2 was extensively characterized by several techniques confirming the obtainment through the proposed route. The supercapacitive properties of the novel structure were evaluated showing a specific capacitance of 190 F g−1 at 0.25 A.g−1. In addition, to the best of our knowledge, this is the first report regarding the chemical synthesis of δ-MnO2 with no dependence of hazardous reducing agent, high temperature or high pressure commonly used to metal oxides production.

Efficiently optimizing the oxygen catalytic properties of the birnessite type manganese dioxide for zinc-air batteries

It is of great significance to design and develop the high-efficiency and low-cost bifunctional oxygen catalysts. Manganese dioxide (MnO2) is one of the most widely studied catalysts for oxygen reduction reaction (ORR) on account of the high reserves and environmental friendliness. Whereas, the catalytic activity of MnO2 for oxygen evolution reaction (OER) is so inferior that it cannot be used as the bifunctional oxygen catalysts. In this work, the assembled nanospheres of cobalt ion intercalated birnessite type MnO2 with a unique lamellar structure are synthesized by a very facile one-step liquid-phase method under mild conditions. Importantly, compared with the pristine MnO2, the optimized cobalt ion intercalated δ-MnO2 (24Co–MnO2) shows the greatly enhanced OER catalytic activity and stability. Specially, 24Co–MnO2 displays a low OER overpotential of 430 mV at 10 mA cm−2 in 0.1 M KOH. In addition, 24Co–MnO2 shows much higher bifunctional oxygen catalytic activity than most of the manganese oxide based catalysts. Moreover, 24Co–MnO2 as the bifunctional oxygen catalyst is assembled in the aqueous and flexible solid-state zinc-air batteries (ZABs), showing the high peak power density and outstanding cycling stability.

Extraction of hidden manganese ore information with combined mining of associated and secondary mineral of remote sensing data in northeast Guizhou

The northeast Guizhou manganese ore area is taken as a study area in the paper. The associated pyrite, chlorite and the secondary manganese oxide were as extraction marks of manganese ore by analyzing the characteristics of the manganese-bearing strata, the ore deposits and the ore bodies. Furthermore, the manganese mineralization information of ASTER image is extracted by using the combined data mining method based on principal component analysis, support vector machine and ant colony algorithm, and then the abnormal region of remote sensing image is delineated. Compared with the abnormal region and the proved deposits, there is a better consistency in spatial distribution. The results show that the combined mining method system for hidden manganese ore based on the remote sensing data of associated and secondary minerals proposed in this paper is feasible and practical for delineating the favorable metallogenic area of Datangpo type manganese ore.

Mineral Materials Coated with and Consisting of MnOx-Characteristics and Application of Filter Media for Groundwater Treatment: A Review.

For groundwater treatment, the technologies involving oxidation on MnOx filter bed are beneficial, common, and effectively used. The presence of MnOx is the mutual feature of filter media, both MnOx-coated mineral materials like quartz sand and gravel, chalcedonite, diatomite, glauconite, zeolite, or anthracite along with consisting of MnOx manganese ores. This review is based on the analysis of research and review papers, commercial data sheets, and standards. The paper aimed to provide new suggestions and useful information for further investigation of MnOx filter media for groundwater treatment. The presented compilations are based on the characteristics of coatings, methods, and conditions of its obtaining and type of filter media. The relationship between the properties of MnOx amendments and the obtained purification effects as well as the commonly used commercial products, their features, and applications have been discussed. The paper concludes by mentioning about improving catalytic/adsorption properties of non-reactive siliceous media opposed to ion-exchange minerals and about possible significance of birnessite type manganese oxide for water treatment. Research needs related to the assessment of the use MnOx filter media to heavy metals removal from groundwater in field operations and to standardize methodology of testing MnOx filter media for water treatment were identified.

Synthesis of isomorphically substituted Ru manganese molecular sieves and their catalytic properties for selective alcohol oxidation

Ruthenium has been incorporated into the framework of the cryptomelane type manganese oxide K-OMS-2 ([Ru]-K-OMS2). Accordingly, Rietveld refinement of the X-ray diffractogram has allowed to estimate changes in the values of cell parameters.

In situ synthesis of MnO2@SiO2–TiO2 nanofibrous membranes for room temperature degradation of formaldehyde

Abstract Catalytic oxidation is an efficient and cost-effective technology to eliminate HCHO, and MnO2 shows excellent performance towards this kind of reactions. In this work, a birnessite type manganese dioxide nanoparticles modified silica-doped titanium dioxide (MnO2@SiO2–TiO2 ) nanofibrous membranes were successfully synthesized by using an electrospinning technique and liquid phase synthesis . It is found that MnO 2@SiO2–TiO2-4 nanofibrous membrane showed the best catalytic activity for HCHO removal. The as-fabricated nanofibrous membranes exhibited good and reversible catalytic oxidation activity towards formaldehyde, and more than 90% of the catalytic performance could remain after 5 testing cycles. The successfully constructed MnO2 nanoparticles decorated soft SiO2–TiO2 nanofibrous membranes, which can be a great promise for effectively solving the problem of environmental remediation.

Single-Pot Self-Assembly of Heteroleptic Mn(I)-Based Aminoquinonato-Bridged Ester/Amide-Functionalized Dinuclear Metallastirrups: Potential Anticancer and Visible-Light-Triggered CORMs.

Multicomponent self-assembly of Mn2(CO)10, a bis-chelating aminoquinonato (ON∩ON) bridge (L), and an ester/amide-functionalized flexible neutral ditopic linker (L′) has resulted into the formation of M2LL′-type manganese(I)-based dinuclear metallastirrups of general formula [{(CO)3Mn(μ-η4-L)Mn(CO)3}(μ-L′)] (1–10). Compounds 1–10 were accomplished via orthogonal bonding of the aminoquinone ligand (2,5-bis(n-butylamino)-1,4-benzoquinone/2,5-bis(phenethylamino)-1,4-benzoquinone) and ditopic pyridyl ligand to manganese carbonyl. The resultant metallastirrups were characterized using elemental analyses and IR, UV–vis, 1H NMR, and electrospray ionization-mass spectroscopic techniques. The molecular structure of 6 was confirmed by single-crystal X-ray diffraction methods. Furthermore, molecular recognition capabilities of 1, 5, 7, and 9 were evaluated with aromatic compounds containing hydroxy/amine functionalities. Anticancer activities of compounds 1−3, 5−7, 9, and 10 were investigated against three cancer cell lines, that is, lung (A549), colon (HCT-15), and cervical (HeLa) as well as on normal cells (HEK 293). Compound 9 showed a broad-spectrum inhibition toward these cancer cells upon exposure to visible light. The myoglobin assay was performed using UV–vis absorption spectroscopy to investigate the visible-light-triggered CO release from 5 and 9 that could be related to their ability to effectively inhibit cancer cells. In addition, morphological studies confirmed the induction of autophagy due to the treatment of cancer cells using compound 9.

Improving the cycle life of cryptomelane type manganese dioxides in aqueous rechargeable zinc ion batteries: The effect of electrolyte concentration

Rechargeable aqueous zinc ion batteries (ZIBs) have many advantages such as high abundance and low cost of Zn, as well as safer battery chemistry in aqueous electrolytes. Cryptomelane-type manganese dioxides (α-MnO2s) are promising cathodes for ZIBs due to their high theoretical capacity, voltage, and abundance. However, α-MnO2 suffers from severe capacity fading as the battery is put through extended charge-discharge cycles. Here, we show that galvanostatic cycling performance of α-MnO2 can significantly be improved at ZnSO4 concentrations below 0.2 M. Low-electrolyte concentrations demonstrated higher discharge capacities and capacity retentions at long battery cycling tests. At 0.1 M ZnSO4, α-MnO2 delivered 62 and 103 mAh/g capacities with 0.3 A/g rate at the 1st and 100th cycles, respectively (166% retention). At a higher charge/discharge rate of 0.9 A/g, α-MnO2 delivered 85 mAh/g capacity at the 500th cycle, where the retention was 167% with respect to the 1st cycle in 0.1 M ZnSO4. On the other hand, at high electrolyte concentrations (>1.0 M), the capacity retentions were below 30% and discharge capacities were below 60 mAh/g after 100 cycles. Better electrochemical performance of α-MnO2 at low electrolyte concentrations is attributed to the suppression of cathode dissolution and the mitigation of the formation of impurity phases such as ZnMn2O4 and ZnMn3O7·xH2O.

Site-Selective Analysis of Nickel-Substituted Li-Rich Layered Material: Migration and Role of Transition Metal at Charging and Discharging

Li-rich type manganese oxides are one of the most promising cathodes for lithium-ion batteries in recent years; thanks to their high energy density. In these cathodes, partial substitution of manga...