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Hydrothermal synthesis of crystalline α-/β-MnO2 nanorods via γ-MnOOH nanorod precursors

ZHANG Weixin, REN Xiangbin, YANG Zeheng, WANG Hua, WANG Qiang, HUANG Fei

《化学科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 365-371 doi: 10.1007/s11705-007-0066-9

摘要: The crystalline -MnO and -MnO nanorods have been successfully prepared via a facile hydrothermal method from -MnOOH nanorods precursor, respectively. The samples were characterized by means of X-ray diff raction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscope (FESEM) and Fourier transformed infrared spectra (FTIR). The morphology and structure of -MnOOH nanorods precursors have a great influence on the crystal structure of the obtained products. The -MnO nanorods are prepared from the 100°C -MnOOH precursor, while the -MnO nanorods are obtained from the 150°C -MnOOH precursor, respectively. Besides, the catalytic activity of the prepared -MnO and -MnO nanorods for the HO decomposition has been investigated comparatively, and the latter shows better catalytic activity.

关键词: obtained     -MnOOH precursor     Besides     high-resolution transmission     precursor    

Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO

Guanglong PANG,Donghui WANG,Yunhong ZHANG,Chunyan MA,Zhengping HAO

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 447-457 doi: 10.1007/s11783-015-0808-8

摘要: MnO microspheres with various surface structures were prepared using the hydrothermal method, and Au/MnO catalysts were synthesized using the sol-gel method. We obtained three MnO microspheres and Au/MnO samples: coherent solid spheres covered with wire-like nanostructures, solid spheres with nanosheets, and hierarchical hollow microspheres with nanoplatelets and nanorods. We investigated the properties and catalytic activities of formaldehyde oxidation at room temperature. Crystalline structures of MnO are the main factor affecting the catalytic activities of these samples, and γ-MnO shows high catalytic performance. The excellent redox properties are responsible for the catalytic ability of γ-MnO . The gold-supported interaction can change the redox properties of catalysts and accelerate surface oxygen species transition, which can account for the catalytic activity enhancement of Au/MnO . We also studied intermediate species. The dioxymethylene (DOM) and formate species formed on the catalyst surface were considered intermediates, and were ultimately transformed into hydrocarbonate and carbonate and then decomposed into CO . A proposed mechanism of formaldehyde oxidation over Au/MnO catalysts was also obtained.

关键词: MnO2 microspheres     Au/MnO2     formaldehyde oxidation     γ-MnO2    

Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic

Jianwei Lu, Lan Lan, Xiaoteng Terence Liu, Na Wang, Xiaolei Fan

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 665-671 doi: 10.1007/s11705-019-1815-2

摘要: A strategy of intensifying the visible light harvesting ability of anatase TiO hollow spheres (HSs) was developed, in which both sides of TiO HSs were utilised for stabilising Au nanoparticles (NPs) through the sacrificial templating method and convex surface-induced confinement. The composite structure of single Au NP yolk-TiO shell-Au NPs, denoted as Au@Au(TiO , was rendered and confirmed by the transmission electron microscopy analysis. Au@Au(TiO showed enhanced photocatalytic activity in the degradation of methylene blue and phenol in aqueous phase under visible light surpassing that of other reference materials such as Au(TiO by 77% and Au@P25 by 52%, respectively, in phenol degradation.

关键词: TiO2 hollow spheres     plasmonic Au nanoparticles     confinement     visible light     photocatalytic degradation    

g-CN-coated MnO hollow nanorod cathode for stable aqueous Zn-ion batteries

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 217-225 doi: 10.1007/s11705-022-2214-7

摘要: Aqueous zinc-ion batteries are attracting considerable attention because of their high safety compared with conventional lithium-ion batteries. Manganese-based materials have been widely developed for zinc-ion batteries cathode owning to their low cost, high security and simple preparation. However, the severe volume expansion and poor stability during charging and discharging limit the further development of manganese-based cathodes. Herein, superior α-MnO2@g-C3N4 was successfully prepared for stable zinc-ion batteries (ZIBs) cathode by introducing g-C3N4 nanosheets. Compared with pure α-MnO2, α-MnO2@g-C3N4 has a specific capacity of 298 mAh·g–1 at 0.1 A·g–1. Even at 1 A·g–1, the α-MnO2@g-C3N4 still retains 100 mAh·g–1 (83.4% retention after 5000 cycles), implying its excellent cycling stability. The α-MnO2@g-C3N4-based cathode has the highest energy density (563 Wh·kg–1) and power energy density (2170 W·kg–1). This work provides new avenues for the development of a wider range of cathode materials for ZIBs.

关键词: α-MnO2 hollow nanorods     g-C3N4     heterojunction     aqueous Zn-ion batteries    

Atomic force microscopy study on the microtopography of natural organic matter and newly formed hydrous MnO2

GUO Jin, MA Jun, SHI Xuehua

《环境科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 251-256 doi: 10.1007/s11783-007-0043-z

摘要: To understand the water purification mechanism of potassium permanganate as a coagulation-aid during the preoxidation process, the microtopography of its reductive products, the newly formed hydrous manganese dioxide and the aged hydrous manganese dioxide, was investigated. The morphology of natural organic matter (NOM) adsorbed by the newly formed hydrous manganese dioxide was also compared with that of NOM alone. By using the tapping mode atomic force microscopy (AFM), the observation results show that the newly formed hydrous manganese dioxide possess a perforated sheet (with a thickness of 0 1.75 nm) as well as some spherical particle structures compared with the hydrous manganese dioxide with 2 h aging time, which demonstrated that the newly formed hydrous manganese dioxide had a large surface area and adsorption capacity. When 1 mmol/L newly formed hydrous manganese dioxide was added, the microtopography of NOM molecules shifted from a loosely dispersed pancake shape (with adsorption height of 5 8.5 nm) to a densely dispersed and uniform spherical structure. These results provide a valid proof that it is the perfect adsorption capability of the newly formed hydrous manganese dioxide that might result in the coagulation aid effect of potassium permanganate preoxidation.

关键词: spherical     microtopography     potassium permanganate     uniform spherical     morphology    

A mini review on chemical fixation of CO 2 : Absorption and catalytic conversion into cyclic carbonates

Weili DAI, Chaktong AU, Shenglian LUO, Shuangfeng YIN,

《化学科学与工程前沿(英文)》 2010年 第4卷 第2期   页码 163-171 doi: 10.1007/s11705-009-0235-0

摘要: In this article, we present our research results on chemical fixation of CO using organobismuth compounds. We fabricated bismuth biphenoate complex, Zn-Mg-Al composite oxides, and SBA-15 or Al-SBA-15 immobilized hydroxyl ionic liquid for CO cycloaddition onto epoxides. The hypervalent bismuth compounds show good ability for association and dissociation with CO. The bismuth biphenolate complexes are catalytically effective for the cycloaddition reaction. The heterogeneous catalysts, viz. Zn-Mg-Al oxides and SBA-15 or Al-SBA-15 immobilized ionic liquid, are efficient for the synthesis of cyclic carbonate from CO and epoxide. It is found that the presence of a trace amount of water can improve the catalytic activity of the immobilized ionic liquid.

关键词: SBA-15     CO cycloaddition     Al-SBA-15 immobilized     CO     dissociation    

Preparation of biomass-derived carbon loaded with MnO as lithium-ion battery anode for improving its

《化学科学与工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11705-023-2376-y

摘要: Biomass-derived carbon materials for lithium-ion batteries emerge as one of the most promising anodes from sustainable perspective. However, improving the reversible capacity and cycling performance remains a long-standing challenge. By combining the benefits of K2CO3 activation and KMnO4 hydrothermal treatment, this work proposes a two-step activation method to load MnO2 charge transfer onto biomass-derived carbon (KAC@MnO2). Comprehensive analysis reveals that KAC@MnO2 has a micro-mesoporous coexistence structure and uniform surface distribution of MnO2, thus providing an improved electrochemical performance. Specifically, KAC@MnO2 exhibits an initial charge-discharge capacity of 847.3/1813.2 mAh·g–1 at 0.2 A·g–1, which is significantly higher than that of direct pyrolysis carbon and K2CO3 activated carbon, respectively. Furthermore, the KAC@MnO2 maintains a reversible capacity of 652.6 mAh·g–1 after 100 cycles. Even at a high current density of 1.0 A·g–1, KAC@MnO2 still exhibits excellent long-term cycling stability and maintains a stable reversible capacity of 306.7 mAh·g–1 after 500 cycles. Compared with reported biochar anode materials, the KAC@MnO2 prepared in this work shows superior reversible capacity and cycling performance. Additionally, the Li+ insertion and de-insertion mechanisms are verified by ex situ X-ray diffraction analysis during the charge-discharge process, helping us better understand the energy storage mechanism of KAC@MnO2.

关键词: biomass-derived carbon     MnO2     lithium-ion batteries     anode material     high reversible capacity    

Facile synthesis of α-MnO

Weixin ZHANG, Wenran ZHAO, Zaoyuan ZHOU, Zeheng YANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 64-72 doi: 10.1007/s11705-014-1402-5

摘要: In this paper, α-MnO micronests composed of nanowires were fabricated via a hydrothermal reaction of MnSO ·H O and K S O solutions. The α-MnO micronests were demonstrated to have a higher adsorption capacity than γ-MnO microspheres due to their large specific surface area. The amount of Congo red adsorbed per unit weight of α-MnO micronests increased significantly from 114 to 282 mg·g with concentration of Congo red solution increasing from 50 to 200 mg·L , but it had a little change with temperature. Kinetics, isotherms and thermodynamics for the adsorption of Congo red on α-MnO micronests were examined. The adsorption process followed the pseudo-second-order kinetics with good correlation. The experimental data were analyzed by Langmuir and Freundlich models, and equilibrium data fitted the Langmuir isotherm very well with maximum monolayer adsorption capacity of 625 mg·g at 22 °C. The adsorption was spontaneous and endothermic according to thermodynamic studies. The experimental results indicate that α-MnO micronests possess a high adsorption capacity and could be employed as a replacement of traditional sorbents.

关键词: MnO2     Congo red     adsorption     kinetics     isotherm     thermodynamics    

配位不饱和Au-O-Ti3+活性位点的构建及其在低温丙烯气相环氧化反应中强化氢气效率的研究 Article

宋钊宁, 闫昊, 袁俊聪, 马宏飞, 曹建琳, 王永祥, 王强, 彭冲, 邓风, 冯翔, 陈德, 杨朝合, 胡永康

《工程(英文)》 2023年 第25卷 第6期   页码 144-156 doi: 10.1016/j.eng.2023.01.008

摘要:

自1998年以来,人们广泛认为Au/Ti基催化剂的Au-O-Ti4+位点是在相对高温条件下丙烯气相环氧化反应的活性位点,但该类催化剂的H2有效利用率普遍较低本工作发现了一种在相对低温条件下丙烯气相环氧化反应的新活性位点Au-O-Ti3+。并且利用原位紫外-可见光谱(operando UV-vis)技术研究了Ti-OOH反应中间体的动态演化过程,结果表明,在Au-O-Ti3+活性位点上的Ti-OOH的生成速率比在Au-O-TiTi3+位点促进了Au和Ti3+之间的电子转移,从而增强了催化剂对O2的吸附能力,有效促进H2O22有效利用率提供了新的思路,而且为低温下丙烯直接气相环氧化反应的工业化推进开辟了新的机会。

关键词: 丙烯环氧化     H2有效利用率     Au/Ti双功能催化剂     配位不饱和Ti位点     密度泛函理论    

Effects of oxidizing environment on digestate humification and identification of substances governing the dissolved organic matter (DOM) transformation process

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1520-0

摘要:

• Liquid digestate humification was investigated under different oxidizing environment.

关键词: Liquid digestate     MnO2     Oxygen     DOM transformation     Humic-like acids    

Epigenetic dysregulation in hepatocellular carcinoma: focus on polycomb group proteins

null

《医学前沿(英文)》 2013年 第7卷 第2期   页码 231-241 doi: 10.1007/s11684-013-0253-7

摘要:

Hepatocellular carcinoma (HCC) development is characterized by the presence of epigenetic alterations, including promoter DNA hypermethylation and post-translational modifications of histone, which profoundly affect expression of a wide repertoire of genes critical for cancer development. Emerging data suggest that deregulation of polycomb group (PcG) proteins, which are key chromatin modifiers repressing gene transcription during developmental stage, plays a causative role in oncogenesis. PcG proteins assemble into polycomb repressive complex 1 (PRC1) and polycomb repressive complex 2 (PRC2) to impose the histone H3 lysine 27 trimethylation (H3K27me3) modification for repression. In this review, we will first recapitulate the mechanisms of two key epigenetic pathways: DNA methylation and histone modifications. Specifically, we will focus our discussion on the molecular roles of PcG proteins. Next, we will highlight recent findings on PcG proteins, their clinicopathological implication and their downstream molecular consequence in hepatocarcinogenesis. Last but not least, we will consider the therapeutic potential of targeting enhancer of zeste homolog 2 (EZH2) as a possible treatment for HCC. Improving our understanding on the roles of PcG proteins in hepatocarcinogenesis can benefit the development of epigenetic-based therapy.

关键词: liver cancer     epigenetics     histone modifications     polycomb group proteins     enhancer of zeste homolog 2 (EZH2)    

Development of new transient liquid phase system Au-Sn-Au for microsystem technology

Kirsten BOBZIN, Nazlim BAGCIVAN, Lidong ZHAO, Stefania FERRARA, Jan PERNE

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 370-375 doi: 10.1007/s11465-010-0107-9

摘要: In the last decade, microsystems evolved to decisive technology in many technical applications. With increasing requirements on the performance of microsystems, more and more dissimilar materials are used in the same assembly. Correspondingly, suitable joining methods are required to fulfil the requirements on good properties of joints. In this study, a new transient liquid phase (TLP) system Au-Sn-Au was developed for potential medical applications in hybrid microsystems. The high and low melting phases Au and Sn were deposited onto diverse substrates by magnetron-sputter-ion plating. The coated substrates were soldered in a microsoldering station under different conditions. The influence of soldering conditions on the microstructure and properties of the joints was investigated. Results show that the developed solder led to high-quality joints that can be used in microsystems for medical applications.

关键词: transient liquid phase     microtechnology     soldering     diffusion     physical vapor deposition (PVD)    

Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1530-y

摘要:

• Simultaneous removal of organic contaminants and Pb(II) was achieved by Mn(VII).

关键词: Permanganate     Pb(II) oxidation     MnO2     pH effect    

Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1726-1734 doi: 10.1007/s11705-022-2188-5

摘要: Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas, in which oxygen transfer is achieved by a redox material. Although lots of efforts have been made to develop high-performance redox materials, a few studies have focused on the redox kinetics. In this work, the kinetics of SrFeO3−δ–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed microreactor. During the methane reduction, combustion occurs before the partial oxidation and there exists a transition between them. The weight loss due to combustion increases, but the transition region becomes less inconspicuous as the reduction temperature increased. The weight loss associated with the partial oxidation is much larger than that with combustion. The rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n = 3 (A3 model) with an activation energy of 59.8 kJ∙mol‒1. The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power law. The partial oxidation is half order with respect to methane pressure. The proposed rate law could well predict the reduction kinetics; thus, it may be used to design and/or analyze a chemical looping reforming reactor.

关键词: chemical looping reforming     SrFeO3−δ/CaO·MnO nanocomposite     reduction kinetics     Avrami–Erofeyev model     pressure-dependent term    

标题 作者 时间 类型 操作

Hydrothermal synthesis of crystalline α-/β-MnO2 nanorods via γ-MnOOH nanorod precursors

ZHANG Weixin, REN Xiangbin, YANG Zeheng, WANG Hua, WANG Qiang, HUANG Fei

期刊论文

Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO

Guanglong PANG,Donghui WANG,Yunhong ZHANG,Chunyan MA,Zhengping HAO

期刊论文

Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic

Jianwei Lu, Lan Lan, Xiaoteng Terence Liu, Na Wang, Xiaolei Fan

期刊论文

g-CN-coated MnO hollow nanorod cathode for stable aqueous Zn-ion batteries

期刊论文

Atomic force microscopy study on the microtopography of natural organic matter and newly formed hydrous MnO2

GUO Jin, MA Jun, SHI Xuehua

期刊论文

Fabrication and photocatalytic ability of an Au/TiO2

Fenghe Lv, Hua Wang, Zhangliang Li, Qi Zhang, Xuan Liu, Yan Su

期刊论文

A mini review on chemical fixation of CO 2 : Absorption and catalytic conversion into cyclic carbonates

Weili DAI, Chaktong AU, Shenglian LUO, Shuangfeng YIN,

期刊论文

Preparation of biomass-derived carbon loaded with MnO as lithium-ion battery anode for improving its

期刊论文

Facile synthesis of α-MnO

Weixin ZHANG, Wenran ZHAO, Zaoyuan ZHOU, Zeheng YANG

期刊论文

配位不饱和Au-O-Ti3+活性位点的构建及其在低温丙烯气相环氧化反应中强化氢气效率的研究

宋钊宁, 闫昊, 袁俊聪, 马宏飞, 曹建琳, 王永祥, 王强, 彭冲, 邓风, 冯翔, 陈德, 杨朝合, 胡永康

期刊论文

Effects of oxidizing environment on digestate humification and identification of substances governing the dissolved organic matter (DOM) transformation process

期刊论文

Epigenetic dysregulation in hepatocellular carcinoma: focus on polycomb group proteins

null

期刊论文

Development of new transient liquid phase system Au-Sn-Au for microsystem technology

Kirsten BOBZIN, Nazlim BAGCIVAN, Lidong ZHAO, Stefania FERRARA, Jan PERNE

期刊论文

Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)

期刊论文

Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial

期刊论文