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https://www.readbyqxmd.com/read/30551109/high-performance-carbon-mno-2-micromotors-and-their-applications-for-pollutant-removal
#1
Xu He, Robert Büchel, Renato Figi, Yucheng Zhang, Yeonkyoung Bahk, Jun Ma, Jing Wang
The wide applications of particulate micromotors in practice, especially in the removal of environmental pollutants, have been limited by the low production yields and demand on high concentration of fuel such as H2 O2 . Carbon/MnO2 micromotors were made hydrothermally using different carbon allotropes including graphite, carbon nanotube (CNT), and graphene for treatment of methylene blue and toxic Ag ions. The obtained micromotors showed high speed of self-propulsion. The highest speed of MnO2 -based micromotors to date was observed for CNT/MnO2 (>2 mm/s, 5 wt% H2 O2 , 0...
December 7, 2018: Chemosphere
https://www.readbyqxmd.com/read/30542685/impact-of-bisphenol-a-influent-concentration-and-reaction-time-on-mno-2-transformation-in-a-stirred-flow-reactor
#2
Sarah Balgooyen, Gabrielle Campagnola, Christina K Remucal, Matthew Ginder-Vogel
Bisphenol A (BPA) is an endocrine disrupting compound commonly found in natural waters at concentrations that are considered harmful for aquatic life. Manganese(iii/iv) oxides are strong oxidants capable of oxidizing organic and inorganic contaminants, including BPA. Here we use δ-MnO2 in stirred flow reactors to determine if higher influent BPA concentrations, or introduction rates, lead to increased polymer production. A major BPA oxidation product, 4-hydroxycumyl alcohol (HCA), is formed through radical coupling, and was therefore used as a metric for polymer production in this study...
December 13, 2018: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/30537692/coaxial-cable-hierarchical-tubular-mno2-fe3o4-c-heterostructures-as-advanced-anode-for-lithium-ion-batteries
#3
Desheng Li, Yu Zhang, Kun Rui, Huijuan Lin, Yan Yan, Xiaoshan Wang, Chao Zhang, Xiao Huang, Jixin Zhu, Wei Huang
Nanostructured manganese oxides have been regarded as promising anodes for lithium-ion batteries (LIBs) due to their high specific capacity, environmental friendliness and low cost. However, as conversion-type electrodes, their scalable utilization is hindered by intrinsically low reaction kinetics, large volume variation and high polarization. Herein, a coaxial-cable tubular heterostructures composed of hollow carbon skeleton, Fe3O4 nanoparticles and ultrathin MnO2 nanosheets from inside out, donated as MnO2@Fe3O4@C, is synthesized via facile two-step hydrothermal process...
December 11, 2018: Nanotechnology
https://www.readbyqxmd.com/read/30535621/mno-2-loaded-microorganism-derived-carbon-for-u-vi-adsorption-from-aqueous-solution
#4
Wei Liao, Huilin Wang, Feize Li, Changsong Zhao, Jun Liu, Jiali Liao, Jijun Yang, Yuanyou Yang, Ning Liu
A low-cost industrial microorganism, Saccharomyces cerevisiae, was employed as a precursor to synthesize carbon/MnO2 composites (MMCs) via an oxidation-reduction reaction and one-step carbonization method for U(VI) adsorption. Scanning electron microscopy and nitrogen adsorption measurement indicated that the microorganism's carbonization could form surface porous structure and increase the specific surface area. Batch experiments showed that the maximum U(VI) adsorption capacity of MMCs reached 207 mg g-1 at [U(VI)]initial  = 25 mg L-1 and pHinitial  = 4...
December 8, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/30529692/enhancing-extracellular-electron-transfer-efficiency-and-bioelectricity-production-by-vapor-polymerization-poly-3-4-ethylenedioxythiophene-mno-2-hybrid-anode
#5
Panpan Liu, Changyong Zhang, Peng Liang, Yong Jiang, Xiaoyuan Zhang, Xia Huang
Electron transfer efficiency in electroactive biofilm is the limiting factor for bioelectricity output of bioelectrochemical system. Here, carbon felt (CF) is coated with manganese dioxide (MnO2 ) which acts as electron mediator in electroactive biofilm. A wrapping layer of conducting Poly 3,4-ethylenedioxythiophene is developed to protect the MnO2 and enhance electron transfer efficiency of MnO2 mediator. The hybrid bioanode (PEDOT/MnO2 /CF bioanode) delivered the highest electron transfer efficiency (6.3 × 10-9  mol cm-2  s-1/2 ) and the highest capacitance of 4...
July 17, 2018: Bioelectrochemistry
https://www.readbyqxmd.com/read/30528011/highly-catalytic-activity-of-mn-sba-15-catalysts-for-toluene-combustion-improved-by-adjusting-the-morphology-of-supports
#6
Yuan Qin, Zhenping Qu, Cui Dong, Yan Wang, Na Huang
Rod-like, hexagonal and fiber-like SBA-15 mesoporous silicas were synthesized to support MnOx for toluene oxidation. This study showed that the morphology of the supports greatly influenced the catalytic activity in toluene oxidation. MnOx supported on rod-like SBA-15 (R-SBA-15) displayed the best catalytic activity and the conversion at 230°C reached more than 90%, which was higher than the other two catalysts. MnOx species consisted of coexisting MnO2 and Mn2 O3 on the three kinds of SBA-15 samples. Large amounts of Mn2 O3 species were formed on the surface and high oxygen mobility was obtained on MnOx supported on R-SBA-15, according to the H2 temperature programmed reduction (H2 -TPR) and X-ray photoelectron spectroscopy (XPS) results...
February 2019: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/30525371/controllable-hortensia-like-mno2-synergized-with-carbon-nanotubes-as-an-efficient-electrocatalyst-for-long-term-metal-air-batteries
#7
Nengneng Xu, Qi Nie, Lingyiqian Luo, Chen-Zhong Yao, Qiaojuan Gong, Yuyu Liu, Xiaodong Zhou, Jinli Qiao
The exploitation of a high-activity and low-cost bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as cathode catalyst is a research priority in metal-air batteries (MeABs). Herein, a novel bifunctional hybrid catalyst of hortensia-like MnO2 synergized with carbon nanotubes (CNTs) (MnO2/CNTs) is controllably synthesized by reasonably designing the crystal structure and morphology as well as electronic arrangement. Based on these strategies, the hybrid accelerates the reaction kinetics and avoids the change of structure...
December 7, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30521672/multi-light-responsive-quantum-dot-sensitized-hybrid-micromotors-with-dual-mode-propulsion
#8
Roberto María Hormigos, Beatriz Jurado Sánchez, Alberto Escarpa
CdS quantum dots/C60 tubular micromotors with chemical/multi-light-controlled propulsion and "on-the-fly" acceleration capabilities are described. "In-situ" growth of CdS quantum dots on the outer fullerene layer impart them with light-responsive properties in connection to inner Pt, Pd or MnO2 layers. This is the first time that visible-light is used to drive bubble propelled tubular micromotors. The micromotors exhibit broad absorption range from 320 to 670 nm and can be wirelessly-controlled by modulating light intensity and peroxide concentration...
December 6, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/30521309/oxide-vs-non-oxide-cathode-materials-for-aqueous-zn-batteries-an-insight-into-the-charge-storage-mechanism-and-consequences-thereof
#9
Pascal Oberholzer, Elena Tervoort, Assil Bouzid, Alfredo Pasquarello, Dipan Kundu
Aqueous Zn-ion batteries, which are being proposed as large scale energy storage solutions due to their unparalleled safety and cost advantage, are comprised of a positive host (cathode) material, a metallic zinc anode, and a mildly acidic aqueous electrolyte (pH ~ 3 - 7). Typically, the charge storage mechanism is believed to be reversible Zn2+ (de)intercalation in the cathode host, with the exception of α-MnO2, for which multiple vastly different and contradicting mechanisms have been proposed. However, our present study, combining electrochemical, operando X-ray diffraction (XRD), electron microscopy in conjunction with energy dispersive X-ray spectroscopy (EDX), and in situ pH evolution analyses on two oxide hosts - tunneled α-MnO2 and layered V3O7·H2O vis-à-vis two non-oxide hosts - layered VS2 and tunneled Zn3[Fe(CN)6]2, suggests that oxides and non-oxides follow two dissimilar charge storage mechanisms...
December 6, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30515458/solid-electrolyte-interphases-for-high-energy-aqueous-aluminum-electrochemical-cells
#10
Qing Zhao, Michael J Zachman, Wajdi I Al Sadat, Jingxu Zheng, Lena F Kourkoutis, Lynden Archer
Electrochemical cells based on aluminum (Al) are of long-standing interest because Al is earth abundant, low cost, and chemically inert. The trivalent Al3+ ions also offer among the highest volume-specific charge storage capacities (8040 mAh cm-3 ), approximately four times larger than achievable for Li metal anodes. Rapid and irreversible formation of a high-electrical bandgap passivating Al2 O3 oxide film on Al have, to date, frustrated all efforts to create aqueous Al-based electrochemical cells with high reversibility...
November 2018: Science Advances
https://www.readbyqxmd.com/read/30508717/identification-of-potentially-mobile-and-persistent-transformation-products-of-reach-registered-chemicals-and-their-occurrence-in-surface-waters
#11
D Zahn, P Mucha, V Zilles, A Touffet, H Gallard, T P Knepper, T Frömel
Transformation of industrial chemicals might be a significant source of hitherto unknown persistent and mobile organic contaminants (PMOC, PM chemicals) present in the aquatic environment. Herein we depicted a three-step strategy consisting of (I) the prioritization of potential PMOC precursors among REACH-registered chemicals, (II) their lab scale transformation through hydrolysis, photolysis, MnO2 oxidation, and biotransformation and subsequent structural elucidation of derived transformation products, and finally (III) the assessment of their environmental relevance...
November 19, 2018: Water Research
https://www.readbyqxmd.com/read/30507346/shape-controllable-synthesis-of-mno-2-nanostructures-from-manganese-contained-wastewater-for-phenol-degradation-by-activating-peroxymonosulfate-performance-and-mechanism
#12
Yaxiong Xiao, Yabo Wang, Yi Xie, Haixiang Ni, Xiang Li, Yongkui Zhang, Tonghui Xie
Nanostructured manganese oxide materials were prepared from manganese-contained wastewater (MW) using a facile hydrothermal method and adopted as catalyst to degrade phenol via activation of peroxymonosulfate (PMS). In the WM environment, δ-MnO2 (flower-like Mn-2 with nanosheets) was transformed to α-MnO2 (needle-like Mn-4 with nanowires). Catalytic evaluation experiments demonstrated that the needle-like MnO2 was highly efficient for phenol removal, with a degradation efficiency of 100% within 15  min at the optimal conditions of catalyst dosage 0...
December 3, 2018: Environmental Technology
https://www.readbyqxmd.com/read/30507152/a-highly-compressible-crosslinked-polyacrylamide-hydrogel-enabled-compressible-zn-mno2-battery-and-a-flexible-battery-sensor-system
#13
Zifeng Wang, Funian Mo, Longtao Ma, Qi Yang, Guojin Liang, Zhuoxin Liu, Hongfei Li, Na Li, Haiyan Zhang, Chunyi Zhi
The fast advancement in flexible and wearable electronics has put up with new requirements on the energy storage device with improved tolerance to deformation apart from offering power output. Despite the tremendous progress in stretchable energy storage devices, the compressional energy storage devices have indeed received limited research attention. In this work, an intrinsically compressible rechargeable battery was proposed using the Zn-MnO2 chemistry and a crosslinked polyacrylamide (PAAm) hydrogel electrolyte...
December 3, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30507142/a-flexible-all-in-one-lithium-sulfur-battery
#14
Minjie Yao, Rui Wang, Zifang Zhao, Yue Liu, Zhiqiang Niu, Jun Chen
The recent boom in flexible and wearable electronic devices has increased the demand for flexible energy storage devices. Flexible lithium-sulfur (Li-S) battery is considered to be a promising candidate due to its high energy density and low cost. Herein, a flexible Li-S battery was fabricated based on a all-in-one integrated configuration, where multi-walled carbon nanotubes/sulfur (MWCNTs/S) cathode, MWCNTs/MnO2 interlayer, polypropylene (PP) separator and Li anode were integrated together by combining blade coating with vacuum evaporation methods...
December 3, 2018: ACS Nano
https://www.readbyqxmd.com/read/30500174/deposition-kinetics-of-colloidal-manganese-dioxide-onto-representative-surfaces-in-aquatic-environments-the-role-of-humic-acid-and-biomacromolecules
#15
Xiaoliu Huangfu, Chengxue Ma, Ruixing Huang, Qiang He, Caihong Liu, Jian Zhou, Jin Jiang, Jun Ma, Yinying Zhu, Muhua Huang
The initial deposition kinetics of colloidal MnO2 on three representative surfaces in aquatic systems (i.e., silica, magnetite, and alumina) in NaNO3 solution were investigated in the presence of model constituents, including humic acid (HA), a polysaccharide (alginate), and a protein (bovine serum albumin (BSA), using laboratory quartz crystal microbalance with dissipation monitoring equipment (QCM-D). The results indicated that the deposition behaviors of MnO2 colloids on three surfaces were in good agreement with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory...
November 30, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/30499652/switchable-photoacoustic-imaging-of-glutathione-using-mno2-nanotubes-for-cancer-diagnosis
#16
Chang Liu, Depeng Wang, Ye Zhan, Lingyue Yan, Qian Lu, Michael Yz Chang, Jingwen Luo, Lidai Wang, Dan Du, Yuehe Lin, Jun Xia, Yun Wu
Glutathione is overexpressed in tumor cells and regulates cancer growth, metastasis and drug resistance. Therefore, detecting glutathione levels may greatly facilitate cancer diagnosis and treatment response monitoring. Photoacoustic (PA) imaging is a noninvasive modality for high-sensitivity, high-resolution, deep-tissue optical imaging. Switchable PA probes that offer signal on/off responses to tumor targets would further improve the detection sensitivity and signal-to-noise ratio of PA imaging. Here we explore the use of MnO2 nanotubes as a switchable and biodegradable PA probe for dynamic imaging of glutathione in cancer...
November 30, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30489060/surface-gradient-ti-doped-mno-2-nanowires-for-high-rate-and-long-life-lithium-battery
#17
Kangning Zhao, Congli Sun, Yanhao Yu, Yifan Dong, Chenyu Zhang, Chongmin Wang, Paul M Voyles, Liqiang Mai, Xudong Wang
Cryptomelane-type α-MnO2 has been demonstrated as a promising anode material for high-energy Li-ion batteries (LIBs) due to its high capacity and intriguing [2 × 2] tunnel structure. However, applications of MnO2 electrode, especially at high current rates and mass active material loading, are limited by the poor mechanical stability, unstable solid electrolyte interphase (SEI) layer, and low reversibility of conversion reactions. Here, we report a design of homogeneous core-shell MnO2 nanowires (NWs) created by near-surface gradient Ti doping (Ti-MnO2 NWs)...
November 29, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30484308/directly-converting-syngas-to-linear-%C3%AE-olefins-over-core-shell-fe3o4-mno2-catalysts
#18
Jie Wang, Yanfei Xu, Guangyuan Ma, Jianghui Lin, Hongtao Wang, Chenghua Zhang, Mingyue Ding
Converting syngas to value-added chemicals via Fischer-Tropsch synthesis (FTS) has attracted much attention, whereas the direct hydrogenation of CO to heavy olefins, especially linear α-olefins (LAOs), remains a challenge. In this study, we designed a core-shell Fe3O4@MnO2 catalyst to realize the direct conversion of syngas to LAOs with high efficiency. This catalyst exhibited an enhanced selectivity of 79.60% for total alkenes and 64.95% for C4+ alkenes, 91% of which are LAOs, at a CO conversion of approximately 75%...
November 28, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30479119/persulfate-activation-on-crystallographic-manganese-oxides-mechanism-of-singlet-oxygen-evolution-for-nonradical-selective-degradation-of-aqueous-contaminants
#19
Shishu Zhu, Xiaojie Li, Jian Kang, Xiaoguang Duan, Shaobin Wang
Minerals and transitional metal oxides of earth-abundant elements are desirable catalysts for in situ chemical oxidation in environmental remediation. However, catalytic activation of peroxydisulfate (PDS) by manganese oxides was barely investigated. In this study, one-dimension manganese dioxides (α- and β-MnO2) were discovered as effective PDS activators among the diverse manganese oxides for selective degradation of organic contaminants. Compared with other chemical states and crystallographic structures of manganese oxide, β-MnO2 nanorods exhibited the highest phenol degradation rate (0...
November 27, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/30476870/engineering-hydrogenated-manganese-dioxide-nanostructures-for-high-performance-supercapacitors
#20
Xiao Ying Liu, Tian Cheng Gong, Jie Zhang, Junyi Ji, Wang Chen Huo, Tong Cao, Yu Xin Zhang, Xianming Zhang, Yunqi Liu
Improving the rate capability of transition metal oxides is of great important for the development of high-performance electrodes for supercapacitors. Here, a novel strategy of hydrogenation to enhance the electron transfer rate of manganese dioxide (MnO2 ) is proposed. Detailed preparative parameters (i.e. hydrogenation temperature and time) are systematically investigated. The hydrogenated MnO2 (H-MnOx ) exhibits modified crystal phase/surface structures and increased electrical conductivity. The prepared H-MnOx exhibits high specific capacitance (640 mF cm-2 at current density of 1 mA cm-2 ), good rate capability (89...
November 20, 2018: Journal of Colloid and Interface Science
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