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Efficient conversion of lignin to alkylphenols over highly stable inverse spinel MnFeO catalysts

《化学科学与工程前沿（英文）》 2023年 第17卷 第8期   页码 1085-1095 doi: 10.1007/s11705-022-2236-1

摘要： The aromatic properties of lignin make it a promising source of valuable chemicals and fuels. Developing efficient and stable catalysts to effectively convert lignin into high-value chemicals is challenging. In this work, MnFe2O4 spinel catalysts with oxygen-rich vacancies and porous distribution were synthesized by a simple solvothermal process and used to catalyze the depolymerization of lignin in an isopropanol solvent system. The specific surface area was 110.5 m2∙g–1, which substantially increased the active sites for lignin depolymerization compared to Fe3O4. The conversion of lignin reached 94%, and the selectivity of alkylphenols exceeded 90% after 5 h at 250 °C. Underpinned by characterizations, products, and density functional theory analysis, the results showed that the catalytic performance of MnFe2O4 was attributed to the composition of Mn and Fe with strong Mn–O–Fe synergy. In addition, the cycling experiments and characterization showed that the depolymerized lignin on MnFe2O4 has excellent cycling stability. Thus, our work provides valuable insights into the mechanism of lignin catalytic depolymerization and paves the way for the industrial-scale application of this process.

关键词： lignin depolymerization     spinel     catalysts     hydrogenation    

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Influences of spinel type and polymeric surfactants on the size evolution of colloidal magnetic nanocrystals

Tahereh R. BASTAMI,Mohammad H. ENTEZARI,Chiwai KWONG,Shizhang QIAO

《化学科学与工程前沿（英文）》 2014年 第8卷 第3期   页码 378-385 doi: 10.1007/s11705-014-1441-y

摘要： Two types of polymeric surfactants, PEG and PVP , were used for the preparation of magnetic ferrite MFe O (M= Mn, Fe) colloidal nanocrystals using a solvothermal reaction method. The effect of spinel type effect on the size evolution of various nanoparticles was investigated. It was found that Fe O nanoparticles exhibited higher crystalinity and size evolution than MnFe O nanoparticles with use of the two surfactants. It is proposed that this observation is due to fewer tendencies of surfactants on the surface of Fe O building blocks nanoparticles than MnFe O . Less amounts of surfactant or capping agent on the surface of nanoparticles lead to the higher crystalibity and larger size. It is also suggested that the type of spinel (normal or inverted spinel) plays a key role on the affinity of the polymeric surfactant on the surface of building blocks.

关键词： spinel type     polymeric surfactant     size evolution     mangnetic ferrite nanoparticle    

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A mini-review of ferrites-based photocatalyst on application of hydrogen production

《能源前沿（英文）》 2021年 第15卷 第3期   页码 621-630 doi: 10.1007/s11708-021-0761-0

摘要： Photocatalytic water splitting for hydrogen production is a promising strategy to produce renewable energy and decrease production cost. Spinel-ferrites are potential photocatalysts in photocatalytic reaction system due to their room temperature magnetization, the high thermal and chemical stability, narrow bandgap with broader visible light absorption, and proper conduction band energy level with strong oxidation activity for water or organic compounds. However, the fast recombination of the photoexcited electrons and holes is a critical drawback of ferrites. Therefore, the features of crystallinity, particle size, specific surface area, morphology, and band energy structure have been summarized and investigated to solve this issue. Moreover, composites construction with ferrites and the popular support of TiO2 or g-C3N4 are also summarized to illustrate the advanced improvement in photocatalytic hydrogen production. It has been shown that ferrites could induce the formation of metal ions impurity energy levels in TiO2, and the strong oxidation activity of ferrites could accelerate the oxidation reaction kinetics in both TiO2/ferrites and g-C3N4/ferrites systems. Furthermore, two representative reports of CaFe2O4/MgFe2O4 composite and ZnFe2O4/CdS composite are used to show the efficient heterojunction in a ferrite/ferrite composite and the ability of resistance to photo-corrosion, respectively.

关键词： photocatalyst     spinel-ferrite     composite     photocatalytic hydrogen production    

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Cu/Cr co-stabilization mechanisms in a simulated AlO-FeO-CrO-CuO waste system

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1408-4

摘要：

• Cu and Cr can be mostly incorporated into CuFexAlyCr2−x−yO4 with a spinel structure.

关键词： Spinel structure     Copper     Chromium     Co-stabilization     Thermal treatment    

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Preparation of lithium ion-sieve and utilizing in recovery of lithium from seawater

Lu WANG, Changgong MENG, Wei MA

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 65-67 doi: 10.1007/s11705-009-0105-9

摘要： Lithium is one of the most important light metals, which is widely used as raw materials for large-capacity rechargeable batteries, light aircraft alloys and nuclear fusion fuel. Seawater, which contains 250 billion tons of lithium in total, has thus recently been noticed as a possible resource of lithium. While, since the average concentration of lithium in seawater is quite low (0.17 mg·L ), enriching it to an adequate high density becomes the primary step for industrial applications. The adsorption method is the most prospective technology for increasing the concentration of lithium in liquid. Among the adsorbents for lithium, the ion-sieve is a kind of special absorbent which has high selectivity for Li , especially the spinel manganese oxides (SMO), which among the series of ion-sieves, has become the most promising adsorption material for lithium. In this study, the SMO ion-sieve was prepared by a coprecipitation method. The preparation conditions were discussed and the sample characters were analyzed. Recovery of Li from seawater were studied in batch experiments using prepared ion-sieve, and the effect of solution pH and the uptake rates were also investigated in different Li solutions.

关键词： lithium     ion-sieve     seawater     spinel manganese oxide    

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NiBO (B = Mn or Co) catalysts for NH-SCR of NO at low-temperature in microwave field

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1696-y

摘要：

● Microwave-assisted catalytic NH3-SCR reaction over spinel oxides is carried out.

关键词： Microwave field     Spinel oxides     NOx     Selective catalytic reduction    

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Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl carbonate synthesis

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 415-422 doi: 10.1007/s11705-012-1214-4

摘要： The catalysts supported on LiAl O (spinel) for vapor phase synthesis of dimethyl carbonate (DMC) from methyl nitrite (MN) have been studied. Their catalytic activities on supports prepared by different methods were evaluated in a continuous reactor. The samples were characterized by powder X-ray diffraction, N adsorption-desorption isotherms, fourier transform infrared spectroscopy and temperature-programmed reduction of H . Li/Al molar ratio and calcination temperature greatly influence the structure of crystalline phase of Li-Al-O oxides. Desirable LiAl O (spinel) was formed at 800°C, while LiAl O (primitive cube) formed at 900°C is undesirable for the reaction. A high Li/Al molar ratio, which was related with LiAlO , also slowed the reaction rate. The electron transfer ability and the interaction with active component are the important properties of the spinel-based supports. The CuCl -PdCl /LiAl O (spinel) with better electron transfer ability and low Pd reduction temperature exhibited a better catalytic ability.

关键词： Wacker-type catalyst     dimethyl carbonate     methyl nitrite     spinel    

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标题 作者 时间 类型 操作

Efficient conversion of lignin to alkylphenols over highly stable inverse spinel MnFeO catalysts

期刊论文

Influences of spinel type and polymeric surfactants on the size evolution of colloidal magnetic nanocrystals

Tahereh R. BASTAMI,Mohammad H. ENTEZARI,Chiwai KWONG,Shizhang QIAO

期刊论文

A mini-review of ferrites-based photocatalyst on application of hydrogen production

期刊论文

Cu/Cr co-stabilization mechanisms in a simulated AlO-FeO-CrO-CuO waste system

期刊论文

Preparation of lithium ion-sieve and utilizing in recovery of lithium from seawater

Lu WANG, Changgong MENG, Wei MA

期刊论文

NiBO (B = Mn or Co) catalysts for NH-SCR of NO at low-temperature in microwave field

期刊论文

Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl carbonate synthesis

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

期刊论文