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Effects of gradient concentration on the microstructure and electrochemical performance of LiNi

Wenming Li, Weijian Tang, Maoqin Qiu, Qiuge Zhang, Muhammad Irfan, Zeheng Yang, Weixin Zhang

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 988-996 doi: 10.1007/s11705-020-1918-9

摘要: Nickel(Ni)-rich layered materials have attracted considerable interests as promising cathode materials for lithium ion batteries (LIBs) owing to their higher capacities and lower cost. Nevertheless, Mn-rich cathode materials usually suffer from poor cyclability caused by the unavoidable side-reactions between Ni ions on the surface and electrolytes. The design of gradient concentration (GC) particles with Ni-rich inside and Mn-rich outside is proved to be an efficient way to address the issue. Herein, a series of LiNi Co Mn O (LNCM622) materials with different GCs (the atomic ratio of Ni/Mn decreasing from the core to the outer layer) have been successfully synthesized via rationally designed co-precipitation process. Experimental results demonstrate that the GC of LNCM622 materials plays an important role in their microstructure and electrochemical properties. The as-prepared GC3.5 cathode material with optimal GC can provide a shorter pathway for lithium-ion diffusion and stabilize the near-surface region, and finally achieve excellent electrochemical performances, delivering a discharge capacity over 176 mAh·g at 0.2 C rate and exhibiting capacity retention up to 94% after 100 cycles at 1 C. The rationally-designed co-precipitation process for fabricating the Ni-rich layered cathode materials with gradient composition lays a solid foundation for the preparation of high-performance cathode materials for LIBs.

关键词: gradient concentration     Ni-rich     LiNi0.6Co0.2-Mn0.2O2     electrochemical performance     lithium-ion battery    

CO2 methanation and co-methanation of CO and CO2 over Mn-promoted Ni/Al2O3 catalysts

Kechao Zhao,Zhenhua Li,Li Bian

《化学科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 273-280 doi: 10.1007/s11705-016-1563-5

摘要: A series of Mn-promoted 15 wt-% Ni/Al O catalysts were prepared by an incipient wetness impregnation method. The effect of the Mn content on the activity of the Ni/Al O catalysts for CO methanation and the co-methanation of CO and CO in a fixed-bed reactor was investigated. The catalysts were characterized by N physisorption, hydrogen temperature-programmed reduction and desorption, carbon dioxide temperature-programmed desorption, X-ray diffraction and high-resolution transmission electron microscopy. The presence of Mn increased the number of CO adsorption sites and inhibited Ni particle agglomeration due to improved Ni dispersion and weakened interactions between the nickel species and the support. The Mn-promoted 15 wt-% Ni/Al O catalysts had improved CO methanation activity especially at low temperatures (250 to 400 °C). The Mn content was varied from 0.86% to 2.54% and the best CO conversion was achieved with the 1.71Mn-Ni/Al O catalyst. The co-methanation tests on the 1.71Mn-Ni/Al O catalyst indicated that adding Mn markedly enhanced the CO methanation activity especially at low temperatures but it had little influence on the CO methanation performance. CO methanation was more sensitive to the reaction temperature and the space velocity than the CO methanation in the co-methanation process.

关键词: Mn promotion     nickel catalysts     CO2 methanation     co-methanation of CO and CO2    

Li4SiO4-coated LiNi0.5Mn1.5O4 as the high performance

Shifeng YANG, Wenfeng REN, Jian CHEN

《能源前沿(英文)》 2017年 第11卷 第3期   页码 374-382 doi: 10.1007/s11708-017-0494-2

摘要: The preparation of Li SiO -coated LiNi Mn O materials by sintering the SiO -coated nickel-manganese oxides with lithium salts using abundant and low-cost sodium silicate as the silicon source was reported. The samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that a uniform and complete SiO coating layer could be obtained at a suitable pH value of 10, which transformed to a good Li SiO coating layer afterwards. When used as the cathode materials for lithium-ion batteries, the Li SiO -coated LiNi Mn O samples deliver a better electrochemical performance in terms of the discharge capacity, rate capability, and cycling stability than that of the pristine material. It can still deliver 111.1 mAh/g at 20 C after 300 cycles, with a retention ratio of 93.1% of the stable capacity, which is far beyond that of the pristine material (101.3 mAh/g, 85.6%).

关键词: lithium-ion batteries     cathode material     LiNi0.5Mn1.5O4     lithium-ion conductor     coating    

Preparation and catalytic performance of La0.8Sr0.2CoO3 supported on the mullite fiber ceramic

ZENG Lingke, LIU Yanchun, LIU Ping′an, WANG Hui, SHUI Anze, DUAN Bilin

《化学科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 372-376 doi: 10.1007/s11705-007-0067-8

摘要: The perovskite-type LaSrCoO supported on the mullite fiber porous ceramics was prepared by means of the impregnating method, and was then characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD); thus we can come to the conclusion that the perovskite-type composite oxidant can disperse on the surface of mullite fiber ceramics. The catalytic activity of the LaSrCoO for NO and CO was evaluated. The effect of the doped 0.1 wt-% PdCl on the catalytic activity of the perovskite-type LaSrCoO was also discussed. The results show that the conversion rates of NO and CO respectively reaches 74.5% and 99% at 601°C without doped Pd, and both reach 100% at 350°C with a little doped Pd.

关键词: porous     conversion     catalytic activity     electron microscopy     perovskite-type LaSrCoO    

Large-scale synthesis of isolated Mn2O3 nanotube/fiber with ferric nitrate as catalyst

ZHANG Aifei, LIU Jiping, L? Guangshu

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 55-58 doi: 10.1007/s11705-007-0011-y

摘要: Isolated MnO nanotubes and nanofibers were prepared very easily at a large scale with the liquid-phase catalysis method. The MnO nanotubes had dimensions of 30 50 nm (exterior diameter) and 0.2 1.0 ?m (length), approximately. The O nanofibers had dimensions of 10 30 nm (diameter) and 0.4 2.0 ?m (length), approximately. Nano-O with different microstructures including nanotubes, nanofibers and nanoparticles could be selectively synthesized by controlling the contents and proportions of potassium permanganate and ferric nitrate. Ferric nitrate was an ideal catalyst for the preparation of O nanotube/fiber. When cobalt nitrate or nickel nitrate was used as catalyst, only amorphous nano-O was synthesized. X-ray diffraction (XRD) result shows that the O nanotube has a crystalline structure different from o-O, t-O, h-O and ?-O.

关键词: different     nickel     exterior diameter     nanotube     XRD    

A microextraction approach for rapid extraction and separation of Mn(II) and Co(II) using saponifiedD2EHPA system

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 963-972 doi: 10.1007/s11705-021-2081-7

摘要: In this paper, we proposed a microextraction approach for the extraction and separation of Mn(II) and Co(II) from sulfate solution simulating leachate of spent lithium-ion battery cathode materials using saponified di-(2-ethylhexyl)phosphoric acid system. The effects of the following operational variables were investigated: equilibrium pH, tri-n-butyl phosphate concentration, saponification rate, two-phase ratio and residence time. The results showcased that the microextractor can reach the extraction equilibrium within 20 s, thereby greatly reducing necessary extraction time comparing to that of conventional processes. The volumetric mass transfer coefficient showed 8–21 times larger than that of batch device. With the help of microextractor, 95% of Mn(II) was extracted with a single theoretical stage at a chosen two-phase ratio of 3:1, and the separation factor βMn/Co was as large as 65.5. In the subsequent stripping step, more than 99% of manganese from loaded phase was easily stripped under optimal conditions. The microextraction approach greatly enhances the mass transfer while enabling a continuous and controllable extraction process within a simple structure design. When extracting spent electrode material with microextractors, the comprehensive recovery of mangenese can reach 96%. The microextraction approach has a good applicability in the spent lithium-ion battery cathode materials recycling at both bench and industrial scales.

关键词: extraction equilibrium     mass transfer coefficient     microextraction     multicomponent extraction     di-(2-ethylhexyl)phosphoric acid    

固体氧化物电解池共电解H2O/CO2研究进展

范慧,宋世栋,韩敏芳

《中国工程科学》 2013年 第15卷 第2期   页码 107-112

摘要: 本文介绍了固体氧化物电解池的结构特点及其用于H2O/CO2的共电解制备H2CO的工作原理,综述了固体氧化物电解池的组成形式,以及单片电解池和电解池堆用于H2O/CO2共电解反应的国内外研究进展,并阐述了提高固体氧化物电解池共电解效率所亟需解决的问题

关键词: 固体氧化物电解池     H2O/CO2共电解     合成气     电解效率     水电解    

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1211-1223 doi: 10.1007/s11705-022-2145-3

摘要: The one-step highly selective oxidation of cyclohexane into cyclohexanone and cyclohexanol as the essential intermediates of nylon-6 and nylon-66 is considerably challenging. Therefore, an efficient and low-cost catalyst must be urgently developed to improve the efficiency of this process. In this study, a Co3O4–CeO2 composite oxide catalyst was successfully prepared through ultrasound-assisted co-precipitation. This catalyst exhibited a higher selectivity to KA-oil, which was benefited from the synergistic effects between Co3+/Co2+ and Ce4+/Ce3+ redox pairs, than bulk CeO2 and/or Co3O4. Under the optimum reaction conditions, 89.6% selectivity to KA-oil with a cyclohexane conversion of 5.8% was achieved over Co3O4–CeO2. Its catalytic performance remained unchanged after five runs. Using the synergistic effects between the redox pairs of different transition metals, this study provides a feasible strategy to design high-performance catalysts for the selective oxidation of alkanes.

关键词: Co3O4–CeO2 composite oxides     cyclohexanone     cyclohexanol     ultrasonic-assisted co-precipitation     selective oxidation     solvent-free    

ZnFe2O4 deposited on BiOCl with exposed (001) and (010) facets for photocatalyticreduction of CO2 in cyclohexanol

Guixian Song, Xionggang Wu, Feng Xin, Xiaohong Yin

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 197-204 doi: 10.1007/s11705-016-1606-y

摘要: ZnFe O -BiOCl composites were prepared by both hydrothermal and direct precipitation processes and the structures and properties of the samples were characterized by various instrumental techniques. The samples were then used as catalysts for the photocatalytic reduction of CO in cyclohexanol under ultraviolet irradiation to give cyclohexanone (CH) and cyclohexyl formate (CF). The photocatalytic CO reduction activities over the hydrothermally prepared ZnFe O -BiOCl composites were higher than those over the directly-precipitated composites. This is because compared to the direct-precipitation sample, the ZnFe O nanoparticles in the hydrothermal sample were smaller and more uniformly distributed on the surface of BiOCl and so more heterojunctions were formed. Higher CF and CH yields were obtained for the pure BiOCl and BiOCl composite samples with more exposed (001) facets than for the samples with more exposed (010) facets. This is due to the higher density of oxygen atoms in the exposed (001) facets, which creates more oxygen vacancies, and thereby improves the separation efficiency of the electron-hole pairs. More importantly, irradiation of the (001) facets with ultraviolet light produces photo-generated electrons which is helpful for the reduction of CO to ·CO . The mechanism for the photocatalytic reduction of CO in cyclohexanol over ZnFe O -BiOCl composites with exposed (001) facets involves electron transfer and carbon radical formation.

关键词: reduction of CO2     cyclohexanol     ZnFe2O4 deposited BiOCl     facet     composite photocatalyst    

Al2O3 and CeO2-promoted MgO sorbents for CO2 capture at moderate

Huimei Yu, Xiaoxing Wang, Zhu Shu, Mamoru Fujii, Chunshan Song

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 83-93 doi: 10.1007/s11705-017-1691-6

摘要: A series of Al O and CeO modified MgO sorbents was prepared and studied for CO sorption at moderate temperatures. The CO sorption capacity of MgO was enhanced with the addition of either Al O or CeO . Over Al O -MgO sorbents, the best capacity of 24.6 mg-CO /g-sorbent was attained at 100 °C, which was 61% higher than that of MgO (15.3 mg-CO /g-sorbent). The highest capacity of 35.3 mg-CO /g-sorbent was obtained over the CeO -MgO sorbents at the optimal temperature of 200 °C. Combining with the characterization results, we conclude that the promotion effect on CO sorption with the addition of Al O and CeO can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO increased the basicity of MgO phase, resulting in more increase in the CO capacity than Al O promoter. Both the Al O -MgO and CeO -MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO sorption-desorption cycles. Compared to Al O , CeO is more effective for promoting the CO capacity of MgO. To enhance the CO capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area.

关键词: CO2 capture     MgO sorbents     Al2O3     CeO2     flue gas    

Study on a green synthetic method of TRPPMCl (M= Fe, Mn, Co)

Jing FAN, Yuanbin SHE, Aixin WANG

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 222-223 doi: 10.1007/s11705-009-0059-y

摘要: A green synthetic method using mixted solvents of di-methyl formamide(DMF) and acids instead of single DMF to synthesize metalloporphyrins(TRPPMCl) from TRPPH and MCl metallization was proposed in this paper. A series of TRPPMCl (M= Fe, Mn, Co) were synthesized through this innovative synthetic method, and these complexes were characterized with various spectroscopic techniques, including IR and UV-Vis spectroscopy. The results showed that the metallization time was markedly reduced from about 10 h to 0.5 h in contrast with the conventional synthetic methods.

关键词: TRPPMCl metalloporphyrins     green synthesis     acid    

Amino acid promoted hydrogen battery system using Mn-pincer complex for reversible CO hydrogenation to

《能源前沿(英文)》 2022年 第16卷 第5期   页码 697-699 doi: 10.1007/s11708-022-0843-7

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    

Excellent performance of Cu-Mn/Ti-sepiolite catalysts for low-temperature CO oxidation

Yong Song,Lisha Liu,Zhidan Fu,Qing Ye,Shuiyuan Cheng,Tianfang Kang,Hongxing Dai

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0908-8

摘要: Sepiolite is clay mineral with a 2:1 layered structure. Ti-pillars have an impact on physicochemical property of the sample. 30Mn5Cu/Ti-Sep shows excellent catalytic activity for the oxidation of CO. The interaction, reducibility, and oxygen mobility govern the activity. The Ti-modified sepiolite (Ti-Sep)-supported Mn-Cu mixed oxide ( Mn5Cu/Ti-Sep) catalysts were synthesized using the co-precipitation method. The materials were characterized by the X-ray diffraction scanning electron microscope, N adsorption-desorption, H -TPR, O -TPD, and XPS techniques, and their catalytic activities for CO oxidation were evaluated. It was found that the catalytic activities of Mn5Cu/Ti-Sep were higher than those of 5Cu/Ti-Sep and 30Mn/Ti-Sep, and the Mn/Cu molar ratio had a distinct influence on catalytic activity of the sample. Among the Mn5Cu/Ti-Sep samples, the 30Mn5Cu/Ti-Sep catalyst showed the best activity (which also outperformed the 30Mn5Cu/Sep catalyst), giving the highest reaction rate of 0.875 × 10 mmol·g ·s and the lowest and of 56°C and 86°C, respectively. Moreover, the 30Mn5Cu/Ti-Sep possessed the best low-temperature reducibility, the lowest O desorption temperature, and the highest surface Mn /Mn atomic ratio. It is concluded that factors, such as the strong interaction between the copper or manganese oxides and the Ti-Sep support, good low-temperature reducibility, and good mobility of chemisorbed oxygen species, were responsible for the excellent catalytic activity of 30Mn5Cu/Ti-Sep.

关键词: Ti-modified sepiolite     Supported Mn-Cu mixed oxide     Low-temperature reducibility     Strong metal-support interaction     CO oxidation    

On the monolayer dispersion behavior of Co3O4 on HZSM-5 support: designing applicable

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1741-1754 doi: 10.1007/s11705-023-2332-x

摘要: Based on monolayer dispersion theory, Co3O4/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia. Co3O4 can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m–2, equaling to a weight percentage around 4.5%. It has been revealed that the quantities of surface active oxygen (O2) and acid sites are crucial for the reaction, which can adsorb and activate NOx and NH3 reactants effectively. Below the monolayer dispersion threshold, Co3O4 is finely dispersed as sub-monolayers or monolayers and in an amorphous state, which is favorable to generate the two kinds of active sites, hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide. However, the formation of crystalline Co3O4 above the capacity is harmful to the reaction performance. 4% Co3O4/ZSM-5, the catalyst close to the monolayer dispersion capacity, possesses the most abundant active O2 species and acidic sites, thereby demonstrating the best reaction performance in all the samples. It is proposed the optimal Co3O4/ZSM-5 catalyst can be prepared by loading the capacity amount of Co3O4 onto HZSM-5 support.

关键词: Co3O4/ZSM-5     NOx-SCR by NH3     monolayer dispersion threshold effect     surface acid sites     surface active O2 anions    

标题 作者 时间 类型 操作

Effects of gradient concentration on the microstructure and electrochemical performance of LiNi

Wenming Li, Weijian Tang, Maoqin Qiu, Qiuge Zhang, Muhammad Irfan, Zeheng Yang, Weixin Zhang

期刊论文

CO2 methanation and co-methanation of CO and CO2 over Mn-promoted Ni/Al2O3 catalysts

Kechao Zhao,Zhenhua Li,Li Bian

期刊论文

Li4SiO4-coated LiNi0.5Mn1.5O4 as the high performance

Shifeng YANG, Wenfeng REN, Jian CHEN

期刊论文

Preparation and catalytic performance of La0.8Sr0.2CoO3 supported on the mullite fiber ceramic

ZENG Lingke, LIU Yanchun, LIU Ping′an, WANG Hui, SHUI Anze, DUAN Bilin

期刊论文

Large-scale synthesis of isolated Mn2O3 nanotube/fiber with ferric nitrate as catalyst

ZHANG Aifei, LIU Jiping, L? Guangshu

期刊论文

A microextraction approach for rapid extraction and separation of Mn(II) and Co(II) using saponifiedD2EHPA system

期刊论文

固体氧化物电解池共电解H2O/CO2研究进展

范慧,宋世栋,韩敏芳

期刊论文

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective

期刊论文

ZnFe2O4 deposited on BiOCl with exposed (001) and (010) facets for photocatalyticreduction of CO2 in cyclohexanol

Guixian Song, Xionggang Wu, Feng Xin, Xiaohong Yin

期刊论文

Al2O3 and CeO2-promoted MgO sorbents for CO2 capture at moderate

Huimei Yu, Xiaoxing Wang, Zhu Shu, Mamoru Fujii, Chunshan Song

期刊论文

Study on a green synthetic method of TRPPMCl (M= Fe, Mn, Co)

Jing FAN, Yuanbin SHE, Aixin WANG

期刊论文

Amino acid promoted hydrogen battery system using Mn-pincer complex for reversible CO hydrogenation to

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

Excellent performance of Cu-Mn/Ti-sepiolite catalysts for low-temperature CO oxidation

Yong Song,Lisha Liu,Zhidan Fu,Qing Ye,Shuiyuan Cheng,Tianfang Kang,Hongxing Dai

期刊论文

On the monolayer dispersion behavior of Co3O4 on HZSM-5 support: designing applicable

期刊论文