Search

The development of efficient and cost-effective electrocatalysts is crucial for achieving a green hydrogen economy through electrocatalytic water splitting. Herein, we report an excellent catalyst, one-dimensional NiS2/NiS/Mn2O3 nanofibers prepared by electrospinning, which exhibits outstanding electrochemical performance in an alkaline solution. We explored effective strategies to construct one-dimensional nanostructures and composite oxides to promote the electrocatalytic performance of transition metal dichalcogenides. At a current density of 20 mA cm−2, it requires an overpotential of 333 mV for OER. Furthermore, NiS2/NiS/Mn2O3 nanofibers maintain good durability even after 1000 cycles. The long-term electrochemical stability test of the catalyst NiS2/NiS/Mn2O3 was implemented at 20 mA cm−2 for 12 h. The potential remained at 99.52%. Therefore, this study demonstrates that NiS2/NiS/Mn2O3 can serve as a viable green hydrogen production electrocatalyst. [ABSTRACT FROM AUTHOR]

This work aims to study the effect of Mn 2 O 3 additions on the electrical properties and microstructure characteristics of a SnO 2 -based ceramic varistor system doped additionally with Sb 2 O 5 , Cr 2 O 3 , and CoO. The specimens were prepared using conventional ceramic processing and homogenized by a high-energy ball milling system using the following composition: (98.99-X) % SnO 2 – 0.05% Cr 2 O 3 – 0.05% Sb 2 O 5 – 1.00% CoO – X% Mn 2 O 3 where X = 0.00, 0.05, 0.10, 0.20, 0.50 and 1% mol. Characterization by TG-DSC/DTA, XRD, XPS, and SEM/EDS, and the proposed chemical and defect-formation reactions allowed the conclusion that Mn 2 O 3 additions produce alterations of the microstructure consisting of the in situ formation of the spinel Co 2 MnO 4 secondary phase and modification of the potential barriers in the intergranular regions, where, in addition, oxygen vacancies are formed. With the 0.05 mol % Mn 2 O 3 , the grain size (average in the range of 2–3 μm) drops by 20 %, thus augmenting the grain boundaries. Altogether, this leads to a decrease in the nonlinearity coefficient (α) and an advantageous displacement of the breakdown electric field (E B). The 0.05 mol % Mn 2 O 3 specimen compares favorably with the reference material by surpassing the E B value by a factor of 8. Elucidation of Mn2+ and Co2+ in 1 mol % Mn 2 O 3 specimens by XPS suggests the role of MnO and CoO as intermediate phases, essential for Co 2 MnO 4 formation. The pathway for in situ formation of Co 2 MnO 4 is set forth based on the above characterization techniques in conjunction with proposed chemical and defect-formation reactions. [ABSTRACT FROM AUTHOR]

Antibiotics in wastewater pose a major threat to human health and environmental safety, and the generation of reactive oxygen species by peroxomonosulfate (PMS) activation is an attractive option for the treatment of treating antibiotic wastewater. However, achieving efficient PMS activation remains challenging due to insufficient electron mobility efficiency. Herein, Co-doped Mn2O3 catalyst (Co5-Mn2O3) is prepared by a simple one-step calcination method, and the degradation performance of the Co5-Mn2O3/PMS system is investigated using ofloxacin (OFX) as the target pollutant, and the removal of OFX reaches 95% within 15 min, which is 12.3-fold enhancement compared with the pristine Mn2O3, and the degradation performance of the Co5-Mn2O3/PMS system shows excellent degradation performance for a variety of pollutants (ciprofloxacin, sulfamethoxazole, tetracycline, rhodamine B, and methyl orange), which demonstrates the potential for practical applications. It is confirmed by X-ray photoelectron spectroscopy that Co doping induces the surface reconstruction of the catalyst and electron migration to achieve the formation of Mn4+-O-Co2+ active sites. Trap experiments show that the electron-rich Co site and the electron-deficient Mn site could effectively activate PMS to generate sulfate radicals and singlet oxygen for the efficient removal of ofloxacin. This work provides a structural modulation method of the active site for controlling the catalytic function, which will provide a new perspective for the rational design of Fenton-like catalysts. [ABSTRACT FROM AUTHOR]

Background and Aim: At present, detailed studies are being conducted to confirm the safety of the use of metal-containing ultrafine particles (UFP) in animal feeding, preventing the possibility of negative effects on productive qualities and physiological state, as well as on the environment and final consumer, that is, humans. Thus, the purpose of this research was to study the safety of cobalt- and manganese-containing UFP (UFP Co3O4, Mn2O3 UFP) together with Origanum vulgare (PB) herb extract in a bioluminescence inhibition test, as well as the effect of this composition on ruminal digestion in vitro. Materials and Methods: The safety of the studied samples was determined using a multifunctional microplate analyzer TECAN Infinite F200 (Tecan Austria GmbH, Austria), recording the luminescence value of the bacterial strain Escherichia coli K12 TG11 (Ecolum, JSC NVO Immunotech, Russia). Dry matter (DM) digestibility studies were performed using the in vitro method on an “artificial rumen” model using an ANKOM Daisy II incubator unit (AD II; USA). The number of protozoa in ruminal fluid was counted in a Goryaev chamber. The bacterial mass was assessed by differential centrifugation followed by drying. This method is based on differences in the sedimentation rate of particles that differ in size and density. Results: UFP Co3O4 and Mn2O3 at concentrations above 1.5 × 10-5 and 1.9 × 10-3 mol/L, respectively, have a pronounced bactericidal effect, suppressing more than 50% of the luminescence of E. coli K12 TG1. The combined use of UFP metals and plant extract increases the luminescence of the test object, indicating its safety. The combined use of UFP and PB increases the digestibility of feed DM in vitro and the number of protozoa in 1 mL of ruminal fluid; however, the combination of UFP Mn2O3 + PB (13.8%) yielded the best result, which is recommended for further in vivo research. Conclusion: Origanum vulgare extract reduces the toxicity of UFP Co3O4 and Mn2O3 in vitro, indicating that their combined use is safer.

The conditions of application of thin semiconductor Mn2O3 films on p-InSe crystalline layered semiconductor substrates at a temperature of 623 K by the spray-pyrolysis method to create anisotypic heterojunctions n-Mn2O3/p-InSe were investigated. InSe is a promising material for photoelectronics. The use of the Mn2O3 film, which is transparent in the region of maximum photosensitivity of InSe, makes it possible to effectively exploit the optical properties of InSe in the fabrication of various semiconductor devices. The advantage of using layered semiconductors in the production of heterojunctions is that high-quality interfaces are obtained even with a significant discrepancy in the parameters of the crystal lattices of the starting materials. This significantly expands the choice of heterojunction materials. Electrical and photoelectric parameters of n-Mn2O3/p-InSe heterojunctions were measured and theoretical models describing them were proposed. The graphical dependencies of I-V characteristics, series resistance, height of the potential barrier and photosensitivity are constructed. It was established that these heterojunctions are photosensitive and have rectifying properties. Using the energy parameters of the starting materials, an energy diagram of the heterojunction was constructed, which allows for the analysis of physical processes in the obtained heterojunctions. Based on the temperature dependence of both direct and reverse I-V characteristics, the dynamics of changes in the energy parameters of the heterojunction with temperature, as well as the mechanisms of current flow through the heterojunction, are established. The spectral photosensitivity of the heterojunction was analyzed. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Leishmaniasis is a group of diseases caused by infection with Leishmania parasites. The lesions that develop as a result of leishmaniasis can vary depending on the species of the parasite and the type of leishmaniasis. Cutaneous leishmaniasis is the most common form of the disease and it results in skin sores or ulcers. Materials with manganese oxide (Mn2O3) nanoparticles and tellurium oxide (TeO2) nanorods have been shown to have antibacterial, antifungal, and antiparasitic effects. The purpose of this study was to ascertain how Mn2O3 and TeO2 nanoparticles affected Leishmania major-caused wound healing in rats. The albino rats were separated into four groups of five once a lesion appeared on their tails. In the two treatment groups, Mn2O3 and TeO2 nanoparticles were injected every day, once a day, intra-wound in three places, and in the meglumine antimoniate group, the drug was injected intramuscularly for five weeks. The albino rats in the negative control group did not receive any medication. The size of the wounds in the group treated with Mn2O3 nanoparticles did not differ significantly from the control group that did not receive treatment, however the diameter of the wounds in the group treated with TeO2 nanorods did change significantly from the control group that did not receive treatment. It was, however, larger than the group that received meglumine antimoniate treatment. TeO2 nanorods, as opposed to Mn2O3 nanoparticles, had an in vivo anti-Leishmanial potential. [ABSTRACT FROM AUTHOR]

Currently, efforts to address the energy needs of large-scale power applications have expedited the development of sodium–ion (Na–ion) batteries. Transition-metal oxides, including Mn2O3, are promising for low-cost, eco-friendly energy storage/conversion. Due to its high theoretical capacity, Mn2O3 is worth exploring as an anode material for Na-ion batteries; however, its actual application is constrained by low electrical conductivity and capacity fading. Herein, we attempt to overcome the problems related to Mn2O3 with heteroatom-doped reduced graphene oxide (rGO) aerogels synthesised via the hydrothermal method with a subsequent freeze-drying process. The cubic Mn2O3 particles with an average size of 0.5–1.5 µm are distributed to both sides of heteroatom-doped rGO aerogels layers. Results indicate that heteroatom-doped rGO aerogels may serve as an efficient ion transport channel for electrolyte ion transport in Mn2O3. After 100 cycles, the electrodes retained their capacities of 242, 325, and 277 mAh g−1, for Mn2O3/rGO, Mn2O3/nitrogen-rGO, and Mn2O3/nitrogen, sulphur-rGO aerogels, respectively. Doping Mn2O3 with heteroatom-doped rGO aerogels increased its electrical conductivity and buffered volume change during charge/discharge, resulting in high capacity and stable cycling performance. The synergistic effects of heteroatom doping and the three-dimensional porous structure network of rGO aerogels are responsible for their excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

Due to its high energy density, non-toxic, economical and efficient, manganese oxide stands out as a promising cathode material for employment in aqueous zinc-ion batteries. However, the Jahn-Teller effect of Mn3+ and manganese dissolution impose limitations on the widespread application of aqueous zinc-ion batteries during charging and discharging. Herein, the Co doped Mn 2 O 3 electrode material is introduced. Co atoms in the low valence state replace Mn in the manganese oxide lattice, which effectively regulates the layer spacing of Mn 2 O 3. This modulation maintains the structural stability of the electrode during cycling, prevents structural collapse, and inhibits manganese dissolution and the Jahn-Teller effect. Additionally, Co doping increased oxygen vacancies and improved the conductivity of zinc-ion batteries. The Co-Mn 2 O 3 electrode exhibits a high specific capacity of 478 mAh·g−1 at 0.1 A g−1 current density, with 93 % capacity retention 1000 cycles at 1 A g−1 current density. This study delves into the role of Co doping in suppressing the Jahn-Teller effect, offering new insights for improving manganese oxide as an anode material for zinc-ion batteries. This study introduces a high-capacity Co-doped Mn₂O₃ electrode material. Cobalt atoms replace manganese in the Mn₂O₃ lattice, effectively regulating layer spacing and maintaining structural stability during cycling. Meanwhile, the introduction of cobalt prevents structural collapse, inhibits manganese dissolution, and suppresses the Jahn-Teller effect. Additionally, Co doping increases oxygen vacancies and improves conductivity. [Display omitted] • Co doping in Mn₂O₃ regulates layer spacing, maintaining structural integrity. • Co suppresses Jahn-Teller distortion of Mn³⁺ and prevents Mn dissolution. • Co doping increases oxygen vacancies, boosting electrode conductivity. [ABSTRACT FROM AUTHOR]

The surface acidity and electron transfer performance of manganese oxide catalysts significantly affected its performance of peroxymonosulfate (PMS) activation. In this work, Mn 2 O 3 catalyst was prepared by the precipitation method. The C-hybridization Mn 2 O 3 (Mn 2 O 3 -D) catalyst prepared with disodium oxalate as a precipitant had more Mn3+ and Lewis acid sites on the surface, promoting the binding of PMS on the catalyst surface, which exhibited the best performance in inducing PMS activation to degrade bisphenol A (BPA). Quenching experiments and in situ electron spin resonance (ESR) results indicated that radicals and singlet oxygen were not the main reactive oxygen species (ROSs) in the advanced oxidation process. The chemical probe experiment of phenylmethylsulfone (PMSO) showed that the ≡ Mn-OOSO 3 - metastable intermediate formed by the binding of PMS with Mn sites on the catalyst surface was important active species for contaminants degradation. Contaminants combined with intermediates on the catalyst surface to form the electron transfer channels, which were directly degraded through oxygen-atom-transfer pathway and single-electron-transfer pathway. And the hybridization of C promoted the electron transfer during this process. This work further elucidated the reaction mechanism of PMS activation by manganese oxides, and proposed new ideas for the design of MnO x catalysts for efficient activation of PMS. [Display omitted] • C-hybridization Mn 2 O 3 is synthesized by using sodium oxalate as a precipitant. • More Mn3+ and Lewis acid sites lead better catalytic activity. • Radicals and 1O 2 are not the main causes of contaminants degradation. • ≡Mn-OOSO 3 - directly degrades contaminants through mediated electron-transfer. [ABSTRACT FROM AUTHOR]

In this article, a flexible self-healing supercapacitor was fabricated by assembling two activated carbon cloth (ACC)/Mn2O3 electrodes and a self-healing physically cross-linked PVA-H2SO4 gel electrolyte. The results show that ACC/Mn2O3 exhibited excellent electrochemical performance (the area specific capacitance at 1 mA/cm2 was 2 264 mF/cm2, and the capacitance retention rate after 10 000 cycles was 93%). The supercapacitors showed excellent flexibility and good self-healing ability, and the capacitance retention rate after 4 cut-healing cycles was about 80.47%.

As well established, the morphology and architecture of electrode materials greatly contribute to the electrochemical properties. Herein, a novel structure of mesoporous coral-like manganese (III) oxide (Mn 2 O 3) is synthesized via a facile solvothermal method coupled with the carbonization under air. When fabricated as anode electrode for lithium-ion batteries (LIBs), the as-prepared Mn 2 O 3 exhibits good electrochemical properties, showing a high discharge capacity of 1090.4 mAh g−1 at 0.1 A g−1, and excellent rate performance of 410.4 mAh g−1 at 2 A g−1. Furthermore, it maintains the reversible discharge capacity of 1045 mAh g−1 at 0.1 A g−1 after 380 cycles, and 755 mAh g−1 at 1 A g−1 after 450 cycles. The durable cycling stability and outstanding rate performance can be attributed to its unique 3D mesoporous structure, which is favorable for increasing active area and shortening Li+ diffusion distance. [ABSTRACT FROM AUTHOR]

Mn2O3/Fe2O3/few layer graphene/sulfur composites were prepared by melted salt method, interlayer catalytic exfoliation, annealing and melt diffusion method in sequence for lithium-sulfur batteries cathode. The three-dimensional conductive network formed by highly conductive few layers graphene provides electron transfer channel, thus promoting the high capacity performance of lithium-sulfur batteries. The metal oxides distributed uniformly on the surface of graphene exhibit strong interaction towards polysulfides, which can restrain the dissolution of polysulfides and shuttle effect and promote the cycling performance of lithium-sulfur batteries. As a result, the Mn2O3/Fe2O3/FLG30/S cathode shows high capacity and cycling performance. The cathode delivers an initial discharging capacity of 886.3 mAh·g-1 with a high capacity retention of 88.1% after 100 cycles at rate of 0.1 C.

Introduction Manganese(III) oxide (Mn 2 O 3 ) is a transition metal oxide that has gained significant attention due to its unique properties and potential applications in various fields, including catalysis, energy storage, and sensing. Dopamine, a neurotransmitter in the human brain, plays a crucial role in regulating several physiological processes as its detection is important in areas such as medical diagnostics and neurochemistry. The synthesis of Mn 2 O 3 can be achieved through methods like precipitation, hydrothermal synthesis, or solid-state reactions. Aims The objective of this study is to synthesize Mn 2 O 3 , characterize its structure and morphology, and investigate its electrochemical properties toward dopamine. Materials and methods Materials used included manganese sulfate (MnSO 4 ), potassium permanganate, deionized water, a Teflon steel autoclave, and a hot air oven. For the synthesis of a hierarchical Mn 2 O 3  rodlike shape, MnSO 4 •H 2 O (8 mmol) and potassium permanganate (8 mmol) were firstly dissolved in deionized water (40 mL) by stirring, which was then transferred to a Teflon-lined stainless steel autoclave (50 mL). This autoclave was sealed and maintained at 90℃ for six hours. Finally, the resultant Mn 2 O 3 rods were collected by filtration, washed with distilled water and absolute ethanol for several times, and dried in air at 80℃. Mn 2 O 3  rods were obtained by the calcinations of the as-prepared Mn 2 O 3  rods at different temperatures. When Mn 2 O 3  rods were treated at 600℃ for six hours in air, Mn 2 O 3  rods could be collected. Results The X-ray diffraction (XRD) analysis shows that Mn 2 O 3  is crystalline in structure and it matched with that of the Joint Committee on Powder Diffraction Standards (JCPDS). The field emission scanning electron microscopy (FE-SEM) shows the morphology of Mn 2 O 3 is a particle with the size of 100 nm. Cyclic voltammetry response shows that compared to bare electrode, modified electrode shows the higher current response which indicates the sensing ability of the dopamine molecule. Conclusion  Mn₂O₃ was prepared using a hydrothermal technique, and the formation of nanoparticles (NPs) was verified through XRD, while the morphology was examined using FE-SEM. The Mn 2 O 3 obtained was utilized in the detection of electrochemical dopamine, showing promise in the development of effective dopamine sensors. This study sets the stage for the integration of Mn₂O₃ into microfluidic systems for ongoing dopamine monitoring, presenting novel prospects for healthcare and neurochemical investigations. The exploration of various surface engineering approaches may additionally improve the electrochemical capabilities of Mn₂O₃ for the advancement of sensor technology., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Suresh et al.)

A simplified sol-gel method that can be scaled up for large-scale production was adopted for the preparation of manganese oxide nanocrystals. Prepared Mn2O3 exhibited micron-sized particles with a nanoporous structure. In the present study, a simple and low-cost strategy has been employed to fabricate nanoporous Mn2O3 with an increased surface area for an electrode/electrolyte interface that improved the conduction of Mn2O3 material. The crystal phase and morphology of the prepared material was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The prepared electrode materials were deposited on a nickel foam substrate to investigate the electrochemical properties. The galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and complex impedance studies confirmed excellent specific capacitance and capacitive behavior of the prepared material. The synthesized Mn2O3/graphene composites exhibited an excellent specific capacitance of 391 F/g at a scan rate of 5 mV/S. Moreover, a specific capacitance of 369 F/g was recorded at a current density of 0.5 A/g using the galvanostatic charge/discharge test. The high porosity of the materials provided a better electrolyte-electrode interface with a larger specific area, thus suggesting its suitability for energy storage applications.

Manganese oxide is a promising material due to its low cost, abundant reserves, and environmental friendliness. However, low cycling performance has been restricting the manganese oxide cathode materials on the road to commercialization. In this paper, Mn 2 O 3 microspheres with a porous structure are prepared by hydrothermal process and then compounded with low dimensional and small-scale carbon dots (CDs), and the obtained Mn 2 O 3 /CDs materials are used to assemble aqueous zinc ion batteries. X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) are used to characterize its structure and morphology, which prove that the composite with CDs do not change the structure of the original material. The morphology of microspheres can increase the surface area of electrolyte-electrode interface, which is beneficial to ion embedding into cathode materials. Compared with pure Mn 2 O 3 , the composite with CDs content of 3% (MC3) has the best electrochemical performance (the discharge specific capacity is 252.7 mAh·g−1 at 0.1 A g−1). Moreover, the reversible capacity of the Mn 2 O 3 /CDs composites is improved due to the inhibition of the dissolution of Mn by the highly conductive CDs. The specific discharge capacity of the Mn 2 O 3 /CDs composites after 300 cycles is 102.8 mAh·g−1, which is 2.3 times higher than that of the pure Mn 2 O 3. • Mn 2 O 3 /CDs porous microspheres prepared by hydrothermal method improves cycling performance. • CDs improves the specific capacity and cycle life of Mn 2 O 3 cathode. • The reaction kinetics of high rate performance of Mn 2 O 3 /CDs is investigated. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy was used to characterize the chemical composition and elemental states of bare and composite Mn2O3 (Mn2O3-Ag, Mn2O3-SnO2) nanomaterials. The target systems were prepared by the initial plasma enhanced-chemical vapor deposition of manganese oxides on alumina substrates, followed by annealing in inert atmospheres and functionalization with Ag and SnO2 by radio frequency-sputtering on the Mn2O3 surface. The survey scans of the fabricated samples, along with detailed spectra of the C 1s, O 1s, Mn 2p, Mn 3s, and, eventually, Ag 3d, Ag MVV, and Sn 3d regions, were collected and analyzed in detail. The obtained results revealed the formation of composite systems characterized by the presence of Mn2O3 free from other manganese oxides and pure SnO2, whereas appreciable Ag oxidation was observed. The O 1s photoelectron peaks could be fitted by means of two components related to lattice oxygen and to hydroxyl groups/oxygen species chemisorbed on surface O defects. The occurrence of the latter could exert a beneficial effect on the system functional behavior in gas sensing and electrocatalytic applications. [ABSTRACT FROM AUTHOR]

The Fe doped Mn2O3 nanoparticles were synthesized by the microwave-assisted method and synthesized samples were further annealed at 5000C and the samples were subjected to analyze structural, optical and magnetic properties. The structural properties of the nanoparticles were characterized by using X-ray diffractometry. XRD pattern revealed that the existence of Mn2O3 with cubic structure and Mn-doped Fe isa rhombohedral lattice structure. FTIR spectroscopy confirmed the formation of Fe-O stretching vibrations. The observed band positioned at 570cm-1 could be due to the stretching vibration of Fe-O bonds. Energy dispersive analysis (EDAX) spectroscopy confirmed the purity, chemical composition of the FeMn2O3 nanoparticles. The structural properties were analyzed by scanning electron microscope (SEM) analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Green Mn2O3 was used to active PDS for removing E3 from real wastewaters. • Effects of substrates of wastewaters on the removal of E3 by Mn 2 O 3 /PDS system. • Combined DFT, LC-MS analyses and ECOSAR to understand the reaction mechanisms. • The degradation pathway and toxicity of intermediates were predicted. While green synthesized Mn 2 O 3 has been used to activate peroxydisulfate (PDS) to degrade estrogens, effective application in real wastewater is less common due to variation in environmental matrices in wastewater. Here, green synthesized Mn 2 O 3 was used as a Fenton-like catalyst to activate PDS for estriol (E3) degradation in wastewater. The results show that the high concentration of K+ and humic acid in wastewater could inhibit the activation process of the Mn 2 O 3 /PDS system, resulting in low removal efficiency of E3 in wastewater. However, when the concentration of PDS was increased to 15 mM, the removal efficiency of E3 in medical wastewater can reach 100 %, because the high PDS concentration increases the main reactive oxygen species singlet oxygen (1O 2) in medical wastewater. XRD and SEM-EDS analysis indicate that the crystal structure of Mn 2 O 3 is stable, with a consistent rice grain-like morphology before and after reaction. XPS results show no obvious changes in the percentages of Mn(II), Mn(III) and Mn(IV) before and after reaction, indicating that Mn 2 O 3 has good stability when degrading E3 in medical wastewater. Based on density functional theory (DFT) calculations, liquid chromatography-mass spectrometry (LC-MS), and ecological structure–activity relationship (ECOSAR) modeling data analysis, the reactive oxygen species produced by the Mn 2 O 3 /PDS system mainly attack the benzene ring structure of E3, where the toxicity of its intermediate products declines significantly after breaking the benzene ring structure. Overall, this work provides greater understanding of the E3 degradation pathway and the toxicity of its degradation products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chemical looping OCM is attractive method for conversion of CH 4 to C 2 H 4. • Qualified oxygen carrier catalyst is particularly desirable but remains challenging. • Na 2 WO 4 -doped Mn 2 O 3 -TiO 2 is a promising catalyst for the CL-OCM reaction. • This catalyst works efficiently at 740 °C via MnTiO 3 ↔ TiO 2 + Mn 2 O 3 redox cycle. • Doping of Na 2 WO 4 benefits the *CH 3 transfer and desorption to form ∙CH 3 radicals. Intrinsic safety chemical looping-oxidative coupling of methane (CL-OCM) is an attractive method for direct conversion of methane to ethylene, but well-qualified oxygen carrier catalyst still remains challenging. Herein, we report a promising Na 2 WO 4 -doped Mn 2 O 3 -TiO 2 catalyst toward high-efficiency CL-OCM process. The standout Na 2 WO 4 /2Mn1Ti (Mn 2 O 3 /TiO 2 weight ratio of 2/1) catalyst, with good cycling performance, achieves a high space time yield of 27.8 (or 22.9) g C2-C3 kg cat −1h−1 with 19.5 % (or 15.7 %) CH 4 conversion and 80 % (or 82.7 %) C 2 -C 3 selectivity at 740 (or 720) oC and a low catalyst/CH 4 weight ratio of 13.5. The TiO 2 substantially lowers the CL-OCM reaction temperature, due to the establishment of a low-temperature light-off "Mn 2 O 3 + TiO 2 ↔ MnTiO 3 " redox cycle with CH 4 /O 2. The enabling role of Na 2 WO 4 in modulating the reaction of Mn 2 O 3 with CH 4 into OCM instead of combustion is theoretically unveiled, which in nature benefits the *CH 3 transfer and spontaneous desorption to form ∙CH 3 radicals. [ABSTRACT FROM AUTHOR]

In this study, the Mn 2 O 3 @In 2 O 3 core-shell structures were prepared by a two-step hydrothermal method for TEA detection. Characterization of the morphological composition reveals that Mn 2 O 3 @In 2 O 3 is a microsphere structure with Mn 2 O 3 as the core and In 2 O 3 as the shell. The results of the gas-sensitive performance tests showed that the response of Mn 2 O 3 @In 2 O 3 to 100 ppm TEA was 47 at 180 °C, which was a significant improvement over the original In 2 O 3 , and it had excellent long-term stability and reproducibility. The improved gas-sensitive properties are due to the special structure of the core-shell material and the successful construction of p-n heterojunctions between the interfaces. • Mn 2 O 3 @In 2 O 3 core-shell microspheres were prepared by a two-step thermal method. • The special structure of core-shell effectively enhances the gas sensitive property of TEA. • Mn 2 O 3 @In 2 O 3 core-shell has excellent response and long-term stability to TEA. [ABSTRACT FROM AUTHOR]

The rational synthesis of hybrid catalysts with diverse electrocatalytically active components for robust oxygen reduction reaction (ORR) is highly desirable for the development of sustainable metal-air batteries. By using melamine as nitrogen and hydrogen precursors, herein, melamine pyrolysis-induced functionalized nitrogen doping was adopted for the construction of nitrogen doped manganese oxides (N-MnO x Rs), which consists of manganese oxyhydroxide (MnOOH) rooted in manganese sesquioxide (Mn 2 O 3) rod, as a robust ORR electrocatalyst. Systematic studies have found that a suitable mass ratio of melamine to β-MnO 2 rods is necessary for the formation of electrocatalytically MnOOH and Mn 2 O 3. The representative N-MnO x Rs exhibits the nano structure consisting of interconnected nonorods, nanowires, and nanoparticles, which not only increases the exposure of more active sites but also enhances microstructure stability. Moreover, the nitrogen doping creates high content of oxygen vacancies, which accelerates electron transmission/transfer of N-MnO x Rs. As a result, the optimal N-MnO x Rs exhibits impressive ORR catalytic performance in a homemade ZAB. The N-MnO x Rs driven ZAB (176.6 mW cm-2; 811 mAh g-1) delivers a high peak power density and large discharging capacitance comparable to Pt/C driven one (178.1 mW cm-2; 800 mAh g-1), displaying a promising application potential. This work provides a functionalized nitrogen doping strategy for rational construction of robust hybrid electrocatalysts for energy conversion. • Functional nitrogen doping strategy was adopted for construction of MnOOH rooted in Mn 2 O 3 rod hierarchical electrocatalyst. • The nano hierarchical feature not only increases exposure of active sites but also enhances microstructure stability. • The representative N-MnO x Rs exhibits robust ORR catalytic performance comparable to Pt/C catalyst in a homemade ZAB. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tetracycline is effectively decontaminated by Mn 2 O 3 @ZIF-8 via PS activation. • OH, O 2 −, 1O 2 and reactive MnII (s) -S 2 O 8 2−* are involved tetracycline degradation. • Zn-O-Mn electron transport channel facilitates the electron transfer in PS activation. • MnII (s) on Mn 2 O 3 @ZIF-8 surface is the dominant sites for active species generation. Advanced oxidation processes (AOPs) based on persulfate (PS) activation is an extremely effective method to removal antibiotics in wastewater. In this process, endowing abundant active sites and rapid electron transfer channel over catalyst are two essential factors for high performance towards decontamination. Herein, a novel core–shell catalyst Mn 2 O 3 @ZIF-8 with large specific surface area was prepared to remove antibiotics via PS activation under visible light irradiation. Intriguingly, the removal efficiency of tetracycline (TC) by Mn 2 O 3 @ZIF-8 with optimal compound ratio was 3.2 times that of original Mn 2 O 3. The characterizations and density functional theory calculations proved that a Zn-O-Mn electron transfer channel was constructed in Mn 2 O 3 @ZIF-8 heterostructure, which greatly promoted electron transport and photogenerated electron-hole separation. In addition, the activation of PS and degradation of pollutants by Mn 2 O 3 @ZIF-8 was a highly surface-dependent reaction. The correlation between surface physicochemical properties and pollutant removal was further established to uncover the dominant active sites for PS activation. The quenching experiments and electron paramagnetic resonance (EPR) tests confirmed that PS was mainly activated by surface active MnII (s) and dissociated into reactive oxygen species OH, O 2 −, and 1O 2 , or formed reactive complexes MnII (s) -S 2 O 8 2−* to induce electron transfer and achieve TC oxidation. Besides, Mn 2 O 3 @ZIF-8 exhibited satisfactory removal of multiple pollutants and actual pharmaceutical wastewater as well as effective detoxification due to the coexistence of the above radicals and non-radicals pathways. The study provides novel insights into the design of high efficiency of Mn-based catalysts for antibiotic wastewater purification. [ABSTRACT FROM AUTHOR]

The purpose of this study is to develop an active, low cost, non-precious, stable, and high-performance catalyst for oxygen reduction reaction (ORR). In this regard, Mn2O3-decorated nitrogen-doped carbon nanosheets (Mn2O3/NC) are fabricated by a two-step strategy involving a hydrothermal method and a solid-state method. In the resultant structures, very fine Mn2O3 nanoparticles with an average size of about 5 nm are strongly attached to nitrogen-doped carbon nanosheets. The role of the Mn2O3 nanoparticles is to provide active sites for ORR, while the presence of the nitrogen-doped carbon not only enhances the conductivity of the overall structure but is also helpful for overall stability. The Mn2O3/NC shows good onset potential (0.80 V@−1 mA/cm2), methanol crossover effect, and stability (90%).

Schematic presentation of a nanocomposite (Fe 3 O 4 – Mn 2 O 3) that was prepared via in-situ method for the magnetic solid phase extraction of Pb2+ at trace levels. Display Omitted This article focuses on adsorption and desorption of Pb2+ on a novel adsorbent consisting of Mn 2 O 3 and Fe 3 O 4. The adsorbent was prepared through combining Sol-Gel and precipitation methods to in-situ magnetization. Decreasing preparation time, synthesizing at room temperature, not using organic solvents are advantages of the presented approach. The characterizations were done by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, alternating gradient force magnetometer and Brunauer-Emmett-Teller. High surface area and strong magnetic property propose the nanocomposite as a magnetic solid phase extraction adsorbent. Under the optimum preconcentration conditions, (a) limit of detection of 0.36 μg L−1, (b) relative standard deviation (n = 5) of 0.94%, (c) preconcentration factor of 33.33 and (d) linearity of dynamic range of 10–200 μg L−1 show the applicability of the adsorbent. The adsorbent was found to be durable for 3 months and efficiently applicable during this time but it is not reusable. To understand the adsorption mechanism, isotherm adsorption, kinetic adsorption and thermodynamic adsorption were established. The sorbent was employed to preconcentrate Pb2+ from water and vegetables samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Hollow double walled Mn 2 O 3 nanocubes were synthesized and its feasibility for hybrid Na-air battery was systematically studied. Highlights • Hollow doubled walled Mn 2 O 3 nanocubes were synthesized by hydrothermal method. • Its feasibility as air cathode for hybrid Na-air battery was analyzed. • The cell displayed 330 mV overpotential gap and maximum of 0.2 W g−1 power density. • It also displayed 90% energy efficiency with good cyclic stability. Abstract Synthesis of the strongly anisotropic materials, such as highly porous hollow double walled cubes are considered excellent approach to maximize the diffusion of electrolytes. Herein, hollow doubled walled (HDW) Mn 2 O 3 nanocubes (NCs) were synthesized by facile hydrothermal method followed by calcination method. The growth of nanocubes were studied by performing hydrothermal reaction at different times ranging from 3 to 9 h. Thereafter, the feasibility of prepared HDW NCs as air cathode in hybrid Na-air battery was systematically investigated. Among all, the sample prepared by 9 h hydrothermal treatment showed superior performance than 3 and 6 h samples. The fabricated hybrid Na-air cell using HDW Mn 2 O 3 NCs displayed 330 mV overpotential gap and 90% electrical energy efficiency at 5 mA g−1 current density, maximum of 0.2 W g−1 power density and good cyclic stability up to 75 cycles which is attributed to the highly porous nature of material that allows efficient diffusion of electrolyte ions and oxygen from air. Thus, present investigation suggests that HDW Mn 2 O 3 NCs can be a potential air cathode and can be utilized in other metal-air battery systems. [ABSTRACT FROM AUTHOR]

The noble metal-doped Mn 2 O 3 catalyst has good activity at low temperature, but the structure-activity relationship between its catalytic activity and surface oxygen oxygens at low temperature is unclear. In this study, Mn 2 O 3 and Ag-Mn 2 O 3 prepared using aerosol pyrolysis method (Mn 2 O 3 -AP and Ag-Mn 2 O 3 -AP), and Ag-Mn 2 O 3 prepared using co-precipitation method (Ag-Mn 2 O 3 -CP) are selected to unveil the effect of oxygen species (Ag O, Mn O, and Mn-O-Mn (Ag-O-Mn)) in CO oxidation. Ag-Mn 2 O 3 -AP has better CO conversion (100%) at 100 °C. Operando TPR-DRIFTS-MS results show that Ag O plays an important role in CO oxidation at low temperatures. Ag O starts to react with CO above 50 °C. Mn-□-Mn (Ag-□-Mn) oxygen vacancies are beneficial for O 2 decomposition and promotes the regeneration of Ag O and Mn O, and Mn-O-Mn (Ag-O-Mn) above 200 °C. It is revealed that Ag O in the Ag-doped Mn 2 O 3 catalyst prepared using aerosol pyrolysis method effectively promoted the oxidation of CO at lower temperature. [Display omitted] • The effects of Ag O, Mn O, Mn-O-Mn, and (Ag-O-Mn) on CO oxidation were investigated. • Ag O plays a key role in CO low-temperature oxidation. • Ag-O-Mn is beneficial for O 2 decomposition and promotes Ag O regeneration. • Mechanisms of CO oxidation by oxygen species is proposed. [ABSTRACT FROM AUTHOR]

Abstract Heterogeneous core@shell nanostructures bring unique synergetic catalytic properties in comparison with their single-component materials, because the two-phase interface could render hybrid junctions with rich redox reactions. Herein, a series of Mn 2 O 3 @CeO 2 core@shell cubes with tunable CeO 2 shell thickness have been controllably synthesized by a facile multi-step process, which involved the annealing treatment of MnCO 3 precursor to produce Mn 2 O 3 microcubes, followed by a refuxing process to deposit a uniform CeO 2 layer on the Mn 2 O 3 surface. The CeO 2 shell was assembled by nanoparticles with sizes in the range of 2–10 nm, and the thickness could be facilely manipulated by changing the Mn/Ce molar ratios of reactants used in the synthetic process. The Mn 2 O 3 @CeO 2 core@shell cubes exhibited enhanced catalytic activity toward CO oxidation compared with both pure CeO 2 and Mn 2 O 3 , which was attributed to the synergistic interaction between CeO 2 and Mn 2 O 3. Impressively, Mn 2 O 3 @CeO 2 -0.1 sample with a proper CeO 2 thickness exhibited the highest catalytic performance, attaining 100% CO conversion at 220 °C. Graphical abstract Heterogeneous Mn 2 O 3 @CeO 2 core@shell cubes with tunable CeO 2 shell thickness were fabricated by a facile multi-step process and exhibited enhanced catalytic activity toward CO oxidation in comparison with pure Mn 2 O 3 and CeO 2. fx1 Highlights • Mn 2 O 3 @CeO 2 core@shell cubes were fabricated by a facile three-step process. • CeO 2 shell thickness could be tuned by variying the feeding amount of Ce(NO 3) 3. • Mn 2 O 3 @CeO 2 core@shell cubes exhibted enhanced CO catalytic oxidation activity. • High activity can be attibuted to the synergistic action between Mn 2 O 3 and CeO 2. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMOs) are a potential candidate for supercapacitor due to its outstanding characteristics such as cheap, abundant and non-toxic. But poor electron conductivity and large volume expansion at charge/discharge process limit their practical application as electrode materials. It is a feasible strategy to design porous TMOs which could provide high surface area and more electroactive sites to improve electrochemical performance. Herein, a porous Mn 2 O 3 was synthesized by hard-template method using MCM-41 as template. It exhibits superior pore property of high specific surface area of 382 m2 g−1. And applied it as electrode material for supercapacitor, the porous Mn 2 O 3 shows higher specific capacitance of 102 F g−1 compared to 4.88 F g−1 and 2.28 F g−1 of two types of block Mn 2 O 3 with surface area 7.27 m2 g−1 and 2.67 m2 g−1 at discharging current density of 0.2 A g−1. Furthermore, it exhibits excellent long cycle stability in that specific capacitance remains stable after 5000 cycles (137% of the initial value). This research demonstrates that the porous Mn 2 O 3 has broad potential as promising electrode materials for supercapacitors. [Display omitted] [ABSTRACT FROM AUTHOR]

Porous Mn2O3microspheres are controllably synthesized by selectively etching MnCO3precursor with HCl solution. Morphologies and microstructures of Mn2O3microspheres are analyzed by SEM, TEM, XRD, and N2sorption technique. The catalytic performances of Mn2O3microspheres for the degradation of methylene blue (MB) are investigated, and the reaction kinetics of MB degradation is also studied. The results show it is feasible to control the morphologies of Mn2O3microspheres by adjusting the concentration of HCl solution, and the well-developed porous Mn2O3microspheres demonstrate good potential on MB degradation. The degradation reactions follow the pseudo-first-order kinetic model, and the degradation capabilities for MB are great dependent on BET surface areas and pore volumes of Mn2O3microspheres. [ABSTRACT FROM AUTHOR]

Mn 2 O 3 exposing faces (2 2 2) and (2 1 1) with higher surface lattice oxygen mobility could efficiently inspire peroxymonosulfate activation. [Display omitted] • Mn 2 O 3 -P exposing (2 1 1) and (2 2 2) faces displays the higher catalytic efficiency. • Faces (2 1 1) and (2 2 2) own the lower migration energy barrier and adsorption energy. • High lattice oxygen migration and MnⅣ-MnIII/Ⅱ conversion enable efficient PMS activation. The rod-like, spherical, flake-like and granular Mn 2 O 3 microcrystals exposing different crystal faces were prepared and used for peroxymonosulfate (PMS) activation to degrade bisphenol A (BPA). Granular Mn 2 O 3 -P exposing (2 1 1) and (2 2 2) crystal faces displayed the superior degradation efficiency toward BPA than the other three samples. DFT results pointed out that the migration energy barriers of lattice oxygen on crystal faces (2 2 2) and (2 1 1) were lower than that of face (4 0 0). Moreover, the adsorption energies of PMS molecules on faces (2 2 2) and (2 1 1) were more negative. The high lattice oxygen migration of faces (2 1 1) and (2 2 2) and MnⅣ-MnIII/Ⅱ conversion were contributory to the generation of oxygen vacancies to adsorb PMS and O 2 , leading to the production of more active species (SO 4 •-, •OH and 1O 2) in the catalytic process. This work contributes an excellent catalyst with efficient catalytic performance and cycle stability for water pollution treatment. [ABSTRACT FROM AUTHOR]

Traditional manganese trioxide (Mn 2 O 3) as anode materials can be applied to lithium-ion batteries (LIBs), where it possesses excellent electrochemical performance. However, the inherent disadvantages of volume change and poor cycling stability during charge/discharge process hinder the application of transition metal oxide (TMO) in LIBs. Herein, we propose a method to derive Mn 2 O 3 from metal-organic framework in order to mitigate volume change and enhance cycling stability, by virtue of the introduction of oxygen vacancies (O V) and stable template-derived structure for boosted lithium storage properties. Interestingly, M-BTEC (pyromellitic acid based MOF) -derived Mn 2 O 3 represented higher specific capacity of 1227.1 mAh g−1 until 200 cycles with the current density of 0.1 A g−1 while M-IN (isonicotinic acid based MOF) shows 723.4 mAh g−1 with exceptional cycling stability. [Display omitted] • Two different ligands were used to synthesized Mn 2 O 3 and both of which possess cyclic stability and unique structure. • Oxygen vacancies was conducive to boost lithium ion storage performance. • M-BTEC and M-IN displays excellent capacity of 1227.1 mAh g−1while M-IN shows 723.4 mAh g−1 (200 cycles at 0.1 A g−1) [ABSTRACT FROM AUTHOR]

Manganese-based oxides are considered as a promising class of zinc storage materials. However, the dissolution problem of manganese-based oxides leads to a sharp decay of its capacity, hindering its further development. Herein, Mn-metal organic framework (Mn-MOF) derived manganese-based oxide hybrids are synthesized and developed to suppress the dissolution of manganese. The incorporation of oxygen vacancies can tune the electronic rearrangement and crystal microstructure via the different calcination atmospheres of air (Mn 2 O 3) and Ar (MnO/C). Furthermore, the oxygen vacancy can effectively improve the conductivity, which promotes the reaction kinetics and electrochemical performance of manganese-based oxide hybrids. In addition, the storage mechanism of manganese-based oxide hybrids with oxygen vacancies on the insertion and de-intercalation of H+/Zn2+ is demonstrated. Oxygen vacancies enriched MnO/C hybrid cathode shows a high specific capacity of 336.8 mAh g−1 (0.1 A g−1) and the reversible capacity retention 73.8 % after 10,000 cycles at 1.0 A g−1, suggesting excellent long-cycle stability. Significantly, the solid-state zinc ions batteries (ZIBs) is assembled and exhibits a reversible capacity of 58.0 mAh g−1 at 1.0 A g−1. These results suggest that oxygen vacancies provide an effective strategy for exploring high-performance MOF-derived cathodes in aqueous batteries. In this work, we calcined Mn-BTC under Ar and air to obtain MnO/C and Mn 2 O 3 respectively. MnO/C has more oxygen vacancies and better electrochemical performance. Applied to zinc ion battery, specific capacity reaches 336.8 mAh g−1 at 0.1 A g−1, showing excellent zinc storage performance. [Display omitted] • MOF derived MnO with bulk oxygen deficiency and carbon coating structure for ZIBs. • The effect of oxygen vacancies on electrochemical performance is analyzed. • PVA gel electrolyte is successfully prepared and MnO/C is applied to all solid state batteries. [ABSTRACT FROM AUTHOR]

Highlights: [•] Single Mn2O3 crystals with different shapes were synthesized. [•] Mn2O3 showed high effectiveness in activation of peroxymonosulfate. [•] Cubic Mn2O3 presented higher catalytic activity than octahedra and truncated octahedra. [•] Phenol degradation on Mn2O3-cubic follows first-order kinetics. [Copyright &y& Elsevier]

Mn 2 O 3 is an exceptional earth-abundant mineral that has been extensively applied in catalytic oxidation because of the strong redox couples like Mn3+/Mn2+ and Mn4+/Mn3+ exposed on Mn 2 O 3 surface. Herein, the catalytic activity of Mn 2 O 3 in photothermal degradation of toluene was regulated by halogens including F-, Cl-, and Br-. As the electronegativity ordered in F (3.98) > O (3.44) > Cl (3.16) > Br (2.96), F- doped Mn 2 O 3 overperforms Cl- doped and Br- doped Mn 2 O 3 in decomposing toluene. DFT theoretical calculation illustrates that F- attracts the shared electrons from Mn to itself, the deviated charge center stretches the adjacent Mn-O bonds and boosts the generation of abundant oxygen vacancies, helping to strengthen the catalytic activity of Mn 2 O 3. Conversely, Mn-O bonds are shortened by Cl- and Br- that have lower electronegativity than O. The multiple electrons circling Cl- and Br- push Mn towards O and squeeze Mn-O bonds, resulting in the formation of passivated Mn 2 O 3. In conjunction with Mn redox couples and oxygen vacancies, 99% of 400 ppm toluene can be eliminated by F- doped Mn 2 O 3 , corresponding mineralization rate is high up to 95.8%. [Display omitted] • Strong redox couples like Mn3+ /Mn2+ and Mn4+/Mn3+ expose on Mn 2 O 3 surface. • Doping highly electronegative F- to create abundant oxygen vacancies in Mn 2 O 3. • DFT theoretical calculation clarifies the Mn-O bonds near F are stretched. • F- prevails over Cl- and Br- in enhancing Mn 2 O 3 's activity. • 99% of 400 ppm toluene can be eliminated with Mn 2 O 3 -F. [ABSTRACT FROM AUTHOR]

Abstract: Cubic and chain-like structure of α-Mn2O3 with a high surface area was prepared by air oxidation of manganese chloride through sol process by adding hexamine and mercaptosuccinic acid as wetting agent, respectively. The as-synthesized products were characterized with X-ray powder diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), and selected area electron diffraction (SAED). The possible formation mechanism of α-Mn2O3 cubic and chain-like nanostructures has been proposed and discussed. [Copyright &y& Elsevier]

Abstract: A simple method established in the present study has proven to be effective on the synthesis of Mn3O4 and Mn2O3 nanocrystals by using mesoporous silicas (SBA-15) as nanoreactor. These catalysts were characterized by XRD, TEM, N2-physisorption and laser Raman spectroscopic techniques. The structures obtained by thermolysis of Mn(II and III) acetylacetonates on SBA-15 were confirmed by XRD and Raman analysis. TEM characterization in combination with N2 physisorption studies reveal that nanoparticles partially occupying the pores of SBA-15. The nanocrystals of Mn3O4 and Mn2O3 on SBA-15 exhibited tremendous catalytic activities during the steady-state CO oxidation at low reaction temperatures (below 523K). The catalytic activity of these catalysts was found to be higher compared with traditional MnO x impregnated on SBA-15 catalysts. For the sake of comparison, the commercial Mn2O3 and Mn3O4 were also tested for the CO oxidation. [Copyright &y& Elsevier]

Abstract: The physicochemical, surface and catalytic properties of pure and doped Fe2O3/Al2O3 solid catalysts with Au and Mn2O3 calcined at 300, 500 and 700°C were investigated. The dopant concentration of Au was varied between 0.4 and 1.6mol%, while Mn2O3 concentration was varied between 1.0 and 8.0mol%. The techniques employed were DTA, XRD, TPR, EDX, nitrogen adsorption at -196°C, CO oxidation by O2 at 225–275°C and H2O2 decomposition in aqueous solution at 30–50°C. The results obtained revealed that the doping of Fe2O3/Al2O3 solids with different amounts of Au and Mn2O3 changed the degree of crystallinity of Al2O3 and Fe2O3 phases. The doping process led to a progressive increase in the specific surface area of the treated solid catalysts to an extent proportional to the amount of Au and Mn2O3 added. This process led also to a progressive increase in the catalytic activities of the investigated solid catalysts towards CO oxidation by O2 and H2O2 decomposition. The doping of solid catalysts with Au calcined at 300, 500 and 700°C exhibited catalytic activity in CO oxidation by O2 higher than those measured for solid catalysts doped with Mn2O3 calcined at the same temperatures. Opposite results have been observed in case of H2O2 decomposition. These findings indicate that the active sites taking part in CO oxidation by O2 are different from those involved in H2O2 decomposition. [Copyright &y& Elsevier]

Abstract: The ketonization of propanoic acid to form 3-pentanone over CeO2-based composite oxides at temperatures of 300–425°C was investigated. A CeO2-based solid solution, CeO2–Mn2O3, was effective for the ketonization. The citrate process was the most appropriate method for preparing a well-dispersed solid solution. In the ketonization of propanoic acid with another linear carboxylic acid, an asymmetric ketone together with two symmetric ketones was formed, and the ketone composition was approximated by a binomial distribution. The reactivity of the carboxylic acid was slightly decreased as its chain length was increased. In contrast to linear aliphatic acids, branched acids were less reactive. Methyl group substituents at the α- and β-positions of carboxylic acids decreased their reactivities in both homo- and cross-ketonization. The lack of an α-hydrogen or the increase in steric hindrance was surmised to be the cause of the decrease in reactivity. [Copyright &y& Elsevier]