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Multivalent manganese oxides with high electrocatalytic activity for oxygen reduction reaction

Xiangfeng Peng, Zhenhai Wang, Zhao Wang, Yunxiang Pan

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 790-797 doi: 10.1007/s11705-018-1706-y

摘要: A noble-metal-free catalyst based on both Mn O and MnO was prepared by using the dielectric barrier discharge technique at moderate temperature. The prepared catalyst shows a higher electrocatalytic activity towards the oxygen reduction reaction than the catalyst prepared by using the traditional calcination process. The enhanced activity could be due to the coexistence of manganese ions with different valences, the higher oxygen adsorption capacity, and the suppressed aggregation of the catalyst nanoparticles at moderate temperature. The present work would open a new way to prepare low-cost and noble-metal-free catalysts at moderate temperature for more efficient electrocatalysis.

关键词: oxygen reduction reaction     manganese oxides     mixed valences of manganese     oxygen adsorption     dielectric barrier discharge    

The role of manganese oxides in the activation of peroxymonosulfate (PMS)

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1158-8

摘要: Manganese oxides (MnOx) have been demonstrated to be effective materials to activate Oxone (i.e., PMS) to degrade various contaminants. However, the contribution of direct oxidation by MnOx to the total contaminant degradation under acidic conditions was often neglected in the published work, which has resulted in different and even conflicting interpretations of the reaction mechanisms. Here, the role of MnOx (as both oxidants and catalysts) in the activation of Oxone was briefly discussed. The findings offered new insights into the reaction mechanisms in PMS-MnOx and provided a more accurate approach to examine contaminant degradation for water/wastewater treatment.

关键词: Peroxymonosulfate     Manganese oxides     Catalyst     Oxidant    

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1255-8

摘要: • Mechanisms of redox reactions of Fe- and Mn-oxides were discussed. • Oxidative reactions of Mn- and Fe-oxides in complex systems were reviewed. • Reductive reaction of Fe(II)/iron oxides in complex systems was examined. • Future research on examining the redox reactivity in complex systems was suggested. Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn2+ , Ca2+, Ni2+, Cr3+ and Cu2+, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

关键词: Iron oxides     manganese oxides     reduction     oxidation     complex systems     reaction kinetics and mechanisms    

Room temperature oxidation of acetone by ozone over alumina-supported manganese and cobalt mixed oxides

Mehraneh Ghavami, Mostafa Aghbolaghy, Jafar Soltan, Ning Chen

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 937-947 doi: 10.1007/s11705-019-1900-6

摘要: Volatile organic compounds (VOCs) are among the major sources of air pollution. Catalytic ozonation is an efficient process for removing VOCs at lower reaction temperature compared to catalytic oxidation. In this study, a series of alumina supported single and mixed manganese and cobalt oxides catalysts were used for ozonation of acetone at room temperature. The influence of augmenting the single Mn and Co catalysts were investigated on the performance and structure of the catalyst. The manganese and cobalt single and mixed oxides catalysts of the formula Mn10%-CoX and Co10%-MnX (where X= 0, 2.5%, 5%, or 10%) were prepared. It was found that addition of Mn and Co at lower loading levels (2.5% or 5%) to single metal oxide catalysts enhanced the catalytic activity. The mixed oxides catalysts of (Mn10%-Co2.5%) and (Mn10%-Co5%) led to acetone conversion of about 84%. It is concluded that lower oxidation state of the secondary metal improves ozone decomposition and oxidation of acetone.

关键词: ozone     VOC     manganese oxides     cobalt oxides     alumina support    

Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selective

Minhua Zhang, Baojuan Huang, Haoxi Jiang, Yifei Chen

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 594-602 doi: 10.1007/s11705-017-1668-5

摘要: A mild deposition method was used to fabricate Mn-based catalysts on a UiO-66 carrier for the selective catalytic reduction of NO by NH (NH -SCR). The catalyst with 8.5 wt-% MnO loading had the highest catalytic activity for NH -SCR with a wide temperature window (100–290 °C) for 90% NO conversion. Characterization of the prepared MnO /UiO-66 catalysts showed that the catalysts had the crystal structure and porosity of the UiO-66 carrier and that the manganese particles were well-distributed on the surface of the catalyst. X-ray photoelectron spectroscopy analysis showed that there are strong interactions between the MnO and the Zr oxide secondary building units of the UiO-66 which has a positive effect on the catalytic activity. The 8.5 wt-% MnO catalyst maintained excellent activity during a 24-h stability test and exhibited good resistance to SO poisoning.

关键词: metal-organic framework     selective catalytic reduction     manganese oxides     deNOx     SO2 resistance    

Visible light induces bacteria to produce superoxide for manganese oxidation

《环境科学与工程前沿(英文)》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1619-y

摘要:

● Term of manganese-oxidizing microorganisms should be reconsidered.

关键词: Mn(II) oxidation     Manganese-oxidizing bacteria     Reactive oxygen species     Mn(III/IV) oxides    

High purity Mn

Xiaoqiang SHAN, Fenghua GUO, Wenqian XU, Xiaowei TENG

《能源前沿(英文)》 2017年 第11卷 第3期   页码 383-400 doi: 10.1007/s11708-017-0485-3

摘要: Developing electrodes with high specific energy by using inexpensive manganese oxides is of great importance for aqueous electrochemical energy storage (EES) using non-Li charge carriers such as Na-or K-ions. However, the energy density of aqueous EES devices is generally limited by their narrow thermodynamic potential window (~1.23 V). In this paper, the synthesis of high purity layered Mn O nanoparticles through solid state thermal treatment of Mn O spinel nanoparticles, resulting in a chemical formula of [Mn ][Mn O ], evidenced by Rietveld refinement of synchrotron-based X-ray diffraction, has been reported. The electro-kinetic analyses obtained from cyclic voltammetry measurements in half-cells have demonstrated that Mn O electrode has a large overpotential (~ 0.6 V) towards gas evolution reactions, resulting in a stable potential window of 2.5 V in an aqueous electrolyte in half-cell measurements. Symmetric full-cells fabricated using Mn O electrodes can be operated within a stable 3.0 V potential window for 5000 galvanostatic cycles, exhibiting a stable electrode capacity of about 103 mAh/g at a C-rate of 95 with nearly 100% coulombic efficiency and 96% energy efficiency.

关键词: manganese oxides Mn5O8     high voltage     aqueous Na-ion storage    

Catalytic combustion of volatile organic compounds using perovskite oxides catalysts—a review

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1649-1676 doi: 10.1007/s11705-023-2324-x

摘要: With the rapid development of industry, volatile organic compounds (VOCs) are gaining attention as a class of pollutants that need to be eliminated due to their adverse effects on the environment and human health. Catalytic combustion is the most popular technology used for the removal of VOCs as it can be adapted to different organic emissions under mild conditions. This review first introduces the hazards of VOCs, their treatment technologies, and summarizes the treatment mechanism issues. Next, the characteristics and catalytic performance of perovskite oxides as catalysts for VOC removal are expounded, with a special focus on lattice distortions and surface defects caused by metal doping and surface modifications, and on the treatment of different VOCs. The challenges and the prospects regarding the design of perovskite oxides catalysts for the catalytic combustion of VOCs are also discussed. This review provides a reference base for improving the performance of perovskite catalysts to treat VOCs.

关键词: perovskite oxides     volatile organic compounds     catalytic combustion     reaction mechanism    

Effects of humic acid and surfactants on the aggregation kinetics of manganese dioxide colloids

Xiaoliu HUANGFU,Yaan WANG,Yongze LIU,Xixin LU,Xiang ZHANG,Haijun CHENG,Jin JIANG,Jun MA

《环境科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 105-111 doi: 10.1007/s11783-014-0726-1

摘要: The aggregation of common manganese dioxide (MnO ) colloids has great impact on their surface reactivity and therefore on their fates as well as associated natural and synthetic contaminants in engineered (e.g. water treatment) and natural aquatic environments. Nevertheless, little is known about the aggregation kinetics of MnO colloids and the effect of humic acid (HA) and surfactants on these. In this study, the early stage aggregation kinetics of MnO nanoparticles in NaNO and Ca(NO ) solutions in the presence of HA and surfactants (i.e., sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVP)) were modeled through time-resolved dynamic light scattering. In the presence of HA, MnO colloids were significantly stabilized with a critical coagulation concentration (CCC) of ~300 mmol·L NaNO and 4 mmol·L Ca(NO ) . Electrophoretic mobility (EPM) measurements confirmed that steric hindrance may be primarily responsible for increasing colloidal stability in the presence of HA. Moreover, the molecular and/or chemical properties of HA might impact its stabilizing efficiency. In the case of PVP, only a slight increase of aggregation kinetics was observed, due to steric reactions originating from adsorbed layers of PVP on the MnO surface. Consequently, higher CCC values were obtained in the presence of PVP. However, there was a negligible reduction in MnO colloidal stability in the presence of 20 mg·L SDS.

关键词: humic acid     surfactant     aggregation kinetics     drinking water     manganese dioxide colloids    

Tripotassium citrate monohydrate derived carbon nanosheets as a competent assistant to manganese dioxide

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 420-432 doi: 10.1007/s11705-021-2065-7

摘要: Production cost, capacitance, and electrode materials safety are the key factors to be concerned about for supercapacitors. In this work, a type of carbon nanosheets was produced through the carbonization of tripotassium citrate monohydrate and nitric acidification. Subsequently, a well-designed manganese dioxide/carbon nanosheets composite was synthesized through hydrothermal treating. The carbon nanosheets served as the substrate for growing the manganese dioxide, regulating its distribution, and preventing it from inhomogeneous dimensions and severe agglomeration. Many manganese dioxide nanosheets grew vertically on the numerous functional groups generated on the surface of the carbon nanosheets during acidification. The synergistic combination of carbon nanosheets and manganese dioxide tailors the electrochemical performance of the composite, which benefits from the excellent conductivity and stability of carbon nanosheets. The carbon nanosheets derived from tripotassium citrate monohydrate are conducive to the remarkable performance of manganese dioxide/carbon nanosheets electrode. Finally, an asymmetric supercapacitor with active carbon as the cathode and manganese dioxide/carbon nanosheets as the anode was assembled, achieving an outstanding energy density of 54.68 Wh·kg–1 and remarkable power density of 6399.2 W·kg–1 superior to conventional lead-acid batteries. After 10000 charge-discharge cycles, the device retained 75.3% of the initial capacitance, showing good cycle stability. Two assembled asymmetric supercapacitors in series charged for 3 min could power a yellow light emitting diode with an operating voltage of 2 V for 2 min. This study may provide valuable insights for applying carbon materials and manganese dioxide in the energy storage field.

关键词: carbon nanosheets     manganese dioxide     asymmetric supercapacitors     energy density     power density    

Catalytic activity of manganese oxide supported on alumina in the synthesis of quinoxalines

Rekha M., H. Kathyayini, N. Nagaraju

《化学科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 415-421 doi: 10.1007/s11705-013-1360-3

摘要: Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques: Brunner-Emmett-Teller-N adsorption-desorption for surface area, temperature programmed desorption of NH and -butyl amine back titration methods for surface acidity, powder X-ray diffraction for textural properties, and Fourier transform infrared spectroscopy for the anionic radicals. The catalytic activity has been determined under heterogeneous conditions in the condensation reaction between -phenylenediamine and benzil. The product purity is checked by thin-layer chromatography and melting point. The products are also analysed by LC-MS and H-NMR techniques. The yields of the products have been found to be good and catalysts exhibited excellent recyclability. The effect of changing the reaction parameters such as temperature, reaction time, amount of the catalyst, nature of solvent and molar ratio of reactants on the yield of the product has been studied. The surface acidity of the catalysts plays an important role in activating the reaction.

关键词: alumina     manganese oxide deposited on alumina     quinoxaline synthesis    

Coextraction of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent

Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

《化学科学与工程前沿(英文)》 2020年 第14卷 第5期   页码 902-912 doi: 10.1007/s11705-019-1887-z

摘要: High-manganese containing vanadium wastewater (HMVW) is commonly produced during the vanadium extraction process from vanadium titano-magnetite. HMVW cannot be reused and discharged directly, and is harmful to the environment and affect product quality due to heavy metals in the wastewater. The wastewater is usually treated by lime neutralization, but valuable metals (especially V and Mn) cannot be recovered. In this study, an efficient and environmentally friendly method was developed to recover valuable metals by using a solvent extraction-precipitation process. In the solvent extraction process, 98.15% of vanadium was recovered, and the V O product, with a purity of 98.60%, was obtained under optimal conditions. For the precipitation process, 91.05% of manganese was recovered as MnCO which meets the III grade standard of HG/T 2836-2011. Thermodynamic simulation analysis indicated that MnCO was selectively precipitated at pH 6.5 while Mg and Ca could hardly be precipitated. The results of X-ray diffraction and scanning electron microscopy demonstrated that the obtained V O and MnCO displayed a good degree of crystallinity. The treated wastewater can be returned for leaching, and resources (V and Mn) in the wastewater were utilized efficiently in an environmentally friendly way. Therefore, this study provides a novel method for the coextraction of V and Mn from HMVW.

关键词: high-manganese containing vanadium wastewater     solvent extraction     carbonate precipitation     vanadium titano-magnetite     valuable metal recovery    

Chemical composition and formation mechanisms in the cathode-electrolyte interface layer of lithium manganese

Sahithya REDDIVARI, Christian LASTOSKIE, Ruofei WU, Junliang ZHANG

《能源前沿(英文)》 2017年 第11卷 第3期   页码 365-373 doi: 10.1007/s11708-017-0500-8

摘要: Lithium manganese oxide (LiMn O ) is a principal cathode material for high power and high energy density electrochemical storage on account of its low cost, non-toxicity, and ease of preparation relative to other cathode materials. However, there are well-documented problems with capacity fade of lithium ion batteries containing LiMn O . Experimental observations indicate that the manganese content of the electrolyte increases as an electrochemical cell containing LiMn O ages, suggesting that active material loss by dissolution of divalent manganese from the LiMn O surface is the primary reason for reduced cell life in LiMn O batteries. To improve the retention of manganese in the active material, it is key to understand the reactions that occur at the cathode surface. Although a thin layer of electrolyte decomposition products is known to form at the cathode surface, the speciation and reaction mechanisms of Mn in this interface layer are not yet well understood. To bridge this knowledge gap, reactive force field (ReaxFF) based molecular dynamics was applied to investigate the reactions occurring at the LiMn O cathode surface and the mechanisms that lead to manganese dissolution. The ReaxFFMD simulations reveal that the cathode-electrolyte interface layer is composed of oxidation products of electrolyte solvent molecules including aldehydes, esters, alcohols, polycarbonates, and organic radicals. The oxidation reaction pathways for the electrolyte solvent molecules involve the formation of surface hydroxyl species that react with exposed manganese atoms on the cathode surface. The presence of hydrogen fluoride (HF) induces formation of inorganic metal fluorides and surface hydroxyl species. Reaction products predicted by ReaxFF-based MD are in agreement with experimentally identified cathode-electrolyte interface compounds. An overall cathode-electrolyte interface reaction scheme is proposed based on the molecular simulation results.

关键词: lithium manganese oxide batteries     reactive force field (ReaxFF)     cathode-electrolyte interface layer     molecular dynamics    

Occurance and control of manganese in a large scale water treatment plant

Youjun CHEN,Feng XIAO,Yongkang LIU,Dongsheng WANG,Ming YANG,Hua BAI,Jiong ZHANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 66-72 doi: 10.1007/s11783-014-0637-1

摘要: The continuous variations of dissolved oxygen (DO), manganese (Mn), pH, and their effect on manganese removal by different water treatment processes are investigated. The results show that the declined DO concentration and pH value in the bottom of reservoir results in the increasing release of Mn from sediment to source water. Manganese concentration increased from 0.1 to 0.4 mg·L under the condition that DO concentration decreased from 12.0 to 2.0 mg·L in raw water. The different water treatment processes exhibited different efficiency on manganese removal. The processes with recycling of the suspended sludge, low elevation velocity in settling tank and slow filter rate, will benefit the manganese removal. During a high release of manganese in raw water, traditional coagulation-sedimentation and filtration could not completely remove Mn, although granular activated carbon filtration (GAC) had been applied. At that case, preoxidation with chlorine or potassium permanganate (KMnO ) was necessary to address the high manganese concentration.

关键词: manganese release     dissolved oxygen     settling filtration     pre-oxidation    

Adsorptive behaviors of humic acid onto freshly prepared hydrous manganese dioxides

LIU Ruiping, LI Guibai, YANG Yanling, HE Wenjie, HAN Hongda

《环境科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 240-245 doi: 10.1007/s11783-007-0041-1

摘要: This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO(s) (δMnO), and investigated the feasibility of employing δMnO for humic acid removal from drinking water. Effects of such parameters as molecular mass of humic acid, kinds of divalent cations on adsorptive behaviors and possible mechanisms involved were investigated. This study indicated that humic acid with higher molecular mass exhibited more tendency of adsorbing onto &MnO than that with lower molecular mass. Ca facilitated more humic acid adsorption than Mg; UV-Vis spectra analysis indicated higher capabilities of Ca coordinating with acidic functional groups of humic acid than that of Mg. Additionally, ζ potential characterization indicated that Ca showed higher potential of increasing ζ potential of &MnO than Mg. Ca of 1.0 mmol/L increased ζ potential of δMnO

关键词: Mg     molecular     functional     UV-Vis spectra     prepared hydrous    

标题 作者 时间 类型 操作

Multivalent manganese oxides with high electrocatalytic activity for oxygen reduction reaction

Xiangfeng Peng, Zhenhai Wang, Zhao Wang, Yunxiang Pan

期刊论文

The role of manganese oxides in the activation of peroxymonosulfate (PMS)

Jianzhi Huang, Huichun Zhang

期刊论文

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

期刊论文

Room temperature oxidation of acetone by ozone over alumina-supported manganese and cobalt mixed oxides

Mehraneh Ghavami, Mostafa Aghbolaghy, Jafar Soltan, Ning Chen

期刊论文

Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selective

Minhua Zhang, Baojuan Huang, Haoxi Jiang, Yifei Chen

期刊论文

Visible light induces bacteria to produce superoxide for manganese oxidation

期刊论文

High purity Mn

Xiaoqiang SHAN, Fenghua GUO, Wenqian XU, Xiaowei TENG

期刊论文

Catalytic combustion of volatile organic compounds using perovskite oxides catalysts—a review

期刊论文

Effects of humic acid and surfactants on the aggregation kinetics of manganese dioxide colloids

Xiaoliu HUANGFU,Yaan WANG,Yongze LIU,Xixin LU,Xiang ZHANG,Haijun CHENG,Jin JIANG,Jun MA

期刊论文

Tripotassium citrate monohydrate derived carbon nanosheets as a competent assistant to manganese dioxide

期刊论文

Catalytic activity of manganese oxide supported on alumina in the synthesis of quinoxalines

Rekha M., H. Kathyayini, N. Nagaraju

期刊论文

Coextraction of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent

Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

期刊论文

Chemical composition and formation mechanisms in the cathode-electrolyte interface layer of lithium manganese

Sahithya REDDIVARI, Christian LASTOSKIE, Ruofei WU, Junliang ZHANG

期刊论文

Occurance and control of manganese in a large scale water treatment plant

Youjun CHEN,Feng XIAO,Yongkang LIU,Dongsheng WANG,Ming YANG,Hua BAI,Jiong ZHANG

期刊论文

Adsorptive behaviors of humic acid onto freshly prepared hydrous manganese dioxides

LIU Ruiping, LI Guibai, YANG Yanling, HE Wenjie, HAN Hongda

期刊论文