检索结果-内蒙古大学图书馆

synthesis of Cr_2AlC from Elemental Powders with Modified Pressureless Spark Plasma Sintering

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(materials Science) 2019年第2期34卷 287-292页

作者：葛梦妮 WANG Xiaofan LI Gaiye LU Chen 张建峰 TU Rong College of Mechanics and Materials Hohai University State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

We introduced a modified pressureless sintering strategy by SPS with a new T-shape die and tapered punches, which helps the evaporation of melted Al and reduces the sample sticking with the inner wall of the die. Thus, the die breaking risk in the sintering process or the de-molding process is avoided at all. At a low temperature and short holding time, a high purity of Cr_2 AlC was obtained in this SPS process from the optimization of different molar ratios of raw materials. Simultaneously, the high porosity of the as-obtained sample was also a distinguishing feature worth noticing. The reaction mechanism for this process was also discussed in detail. This study presented a new venue for future development of high purity "MAX" materials and others related materials by a modified pressureless sintering strategy.

关键词： pressureless spark plasma sintering Cr2AlC reaction mechanism

Operando Selenium Treatment Towards Enhanced Cyclic Stability for Single-Crystal Ni-Rich Cathode at Ultra-High Voltage of 4.7 V

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Zhang, Zhi Ding, Xiang He, Xinyou Gong, Yang Xiao, Biaobiao Shen, Jixue Ou, Xing Hunan Provincial Key Laboratory of Water Treatment Functional Materials Hunan Provincial Key Laboratory for Control Technology of Distributed Electric Propulsion Aircraf College of Chemistry and Materials Engineering Hunan University of Arts and Science Changde415000 China Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and Environment Central South University Changsha410083 China Institute of Advanced Battery Materials and Devices Faculty of Materials and Manufacturing Beijing University of Technology Beijing100124 China Tianmu Lake Institute of Advanced Energy Storage Technologies Co. Ltd Liyang213300 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

Developing high-voltage (≥4.3 V vs Li/Li+) single-crystal Ni-rich LiNixCoyMn1-x-yO2 offers an enticing strategy to achieve high energy density for lithium-ion batteries. However, at high-voltage operation, the cathode will be vulnerable to induce the intrinsic Oα- (α 0.6Co0.1Mn0.3O2 (SC-NCM) cathode materials by introducing the surface Se element, exhibiting an "anti-aging" effect of inhibiting the escape of oxygen on SC-NCM particles during the ultra-high voltage (4.7 V) cycling. Both theoretical calculation and experimental results confirm that the outside-in nanostructure would substitute some mobile Oα- at the surface of highly charged SC-NCM particle, stabilizing the oxygen lattice and suppressing O2 release during long-term cycling. Meanwhile, the surface modification of thin Se layer will alleviate the parasitic reactions and improve the electronic conductivity. Under the synergistic strategy of surface modification and interface doping, the obtained SC-NCM exhibits boosted cyclic stability in coin half-cell and pouch full-cell simultaneously. Therefore, the reversible capacity of LiNi0.6Co0.1Mn0.3O2 at high voltage is competitive with comercial LiNixCoyMn1-x-yO2 (x ≥ 0.8), demonstrating more superior safety ability and cyclic property. It provides an effective approach for improving the long-term performance of Ni-rich cathode materials for practical application under ultra-high working voltage. © 2023, The Authors. All rights reserved.

关键词： Single crystals

Improved nitrogen reduction electroactivity by unique MoS_(2)‐SnS_(2) heterogeneous nanoplates supported on poly(zwitterionic liquids)functionalized polypyrrole/graphene oxide

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2022年第5期43卷 1341-1350页

作者： Hui Mao Haoran Yang Jinchi Liu Shuai Zhang Daliang Liu Qiong Wu Wenping Sun Xi‐Ming Song Tianyi Ma Institute of Clean Energy Chemistry Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced MaterialsCollege of ChemistryLiaoning UniversityShenyang 110036LiaoningChina Centre for Translational Atomaterials Swinburne University of TechnologyHawthornVIC 3122Australia School of Materials Science and Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027ZhejiangChina

Unique MoS_(2)‐SnS_(2)heterogeneous nanoplates have successfully in‐situ grown on poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide(PVIPS/PPy/GO).PVIPS can attract heptamolybdate ion(Mo7O246−)and Sn^(4+)as the precursors by the ion‐exchange,resulting in the simultaneous growth of 1T’‐MoS2 and the berndtite‐2T‐type hexagonal SnS_(2)by the interfacial induced effect of *** obtained MoS_(2)‐SnS_(2)/PVIPS/PPy/GO can serve as electrocatalysts,exhibiting good NRR performance by the synergistic *** semi‐conducting SnS_(2)would limit the surface electron accessibility for suppressing HER process of 1T’‐MoS_(2),while metallic 1T’‐MoS_(2)might efficiently improve the NRR electroactivity of SnS_(2)by the creation of Mo‐Sn‐Sn trimer catalytic ***,the irreversible crystal phase transition has taken place during the NRR *** 1T’‐MoS_(2)and SnS_(2)have electrochemically reacted with N_(2),and irreversibly converted into Mo^(2)N and SnxNz due to the formation of Mo−N and Sn−N bonding,meanwhile,partial SnS_(2) has been irreversibly evolved into SnS due to the reduction by the power source in the electrochemical *** would put forward a new design idea for optimizing the preparation method and electrocatalytic activity of transition metal dichalcogenides.

关键词： MoS_(2) SnS_(2) Poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide Nitrogen reduction reaction Irreversible crystal phase transition

In Situ Programming Acid-Base Pair Proton-Conductive Channels of Perfluorosulfonic Acid Membrane for Fuel Cells

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Zhang, Wenxing Zhao, Shengqiu Wang, Rui Zhang, Aojie Huang, Yi Tang, Haolin State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen Valley Foshan528200 China State Key Laboratory of Automotive Safety and Energy School of vehicle and Mobility Tsinghua University Beijing100084 China

The development of rapid and dependable proton transport channels is crucial for proton exchange membrane fuel cells (PEMFCs) operating in low humidity conditions. Herein, an NH-Zr framework rich in basic sites was constructed in situ in a perfluorosulfonic acid solution, and PFSA-NH-Zr hybrid proton exchange membranes were prepared. The introduced NH-Zr framework successfully induced proton conducting groups (-SO3H) reorganization along the NH-Zr framework, resulting in the formation of fast ion transport channels. Meanwhile, under low humidity, the acid-base pairs between N-H (N-H-Zr framework) and -SO3H (PFSA) promoted the protonation/deprotonation and the subsequent proton leap via the Grotthuss processes. Especially, the hybrid membrane PFSA-NH-Zr-1 with suitable NH-Zr content had a promising proton conductivity of 0.031 S/cm at 80°C, 40% RH, and 0.292 S/cm at 80°C, 100% RH, which were approximately 33% and 40% higher than the pristine PFSA membrane (0.023 S/cm and 0.209 S/cm), respectively. In addition, the maximum power density of the hybrid PEM was 0.726 W/cm2, which was nearly 20% higher than the pristine PFSA membrane (0.604 W/cm2) under 80°C, 40% RH. This work established a referable strategy for developing high-performance proton exchange membranes under low RH conditions. © 2022, The Authors. All rights reserved.

关键词： Proton conductivity

Operando Selenium Treatment Towards Enhanced Cyclic Stability for Single-Crystal Ni-Rich Cathode at Ultra-High Voltage of 4.7 V

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Zhang, Zhi Ding, Xiang He, Xinyou Gong, Yang Xiao, Biaobiao Shen, Jixue Ou, Xing Engineering Research Center The Ministry of Education for Advanced Battery Materials School of Metallurgy and Environment Central South University Changsha410083 China Hunan Provincial Key Laboratory of Water Treatment Functional Materials Hunan Provincial Key Laboratory for Control Technology of Distributed Electric Propulsion Aircraf College of Chemistry and Materials Engineering Hunan University of Arts and Science Changde415000 China Institute of Advanced Battery Materials and Devices Faculty of Materials and Manufacturing Beijing University of Technology Beijing100124 China Tianmu Lake Institute of Advanced Energy Storage Technologies Co. Ltd Liyang213300 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

关键词： Single crystals

Phosphorus Coordinated Co/Se2 Heterointerface Nanowires: In-Situ Catalyst Reconstruction Toward Efficient Overall Water Splitting in Alkaline and Seawater Media

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Boakye, Felix Ofori Harrath, Karim Tabish, Mohammad Yasin, Ghulam Owusu, Kwadwo Asare Ajmal, Saira Zhang, Wenbin Zhang, Haining Zhao, Wei Institute for Advanced Study Shenzhen University Shenzhen518060 China College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518060 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Department of Chemistry Guangdong Provincial Key Laboratory of Catalytic Chemistry Southern University of Science and Technology Guangdong Shenzhen518055 China College of Materials Science and Engineering Beijing University of Chemical Technology Beijing100029 China

Designing a highly efficient electrocatalyst to realize overall water splitting is vital, yet identifying the active site remains an ongoing challenge. Herein, the electrochemical in situ surface activation of P@Co/Se2-NW/CC was investigated to understand the enhanced OER activity of P@Co/Se2-NW/CC. The incorporation of phosphorus is thought to increase the number of vacancies surrounding the Co cations in the initial Co/Se2 and speed up the structural change into "active species" like cobalt oxide/oxyhydroxide. The as-synthesized P@Co/Se2-NW/CC required a low overpotential for OER (η20 = 170 and 200 mV) and HER (η10 = 52 and 82 mV), respectively, in alkaline water and alkaline seawater media. In situ FTIR and Post characterization unraveled the existence of surface-bounded Co oxide species on P@Co/Se2-NW/CC after OER catalysis, which is responsible for the enhanced electrocatalytic activity. This study offers a valuable strategy for developing noble-metal-free bifunctional catalysts for efficient hydrogen generation from alkaline seawater and alkaline water electrolysis. © 2023, The Authors. All rights reserved.

关键词： Oxygen

Tunable Interlayer Spacings Ti3c2tx Mxene@Ni for Enhanced Electromagnetic Microwave Absorption

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Song, Jingyu Shen, Yongqian Zhang, Guibin Sun, Mingxuan Han, Mengyao Du, Xueyan School of Materials Science & Engineering State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of Technology Lanzhou730050 China Shouhang Hi-TechEnergy Technology Co. Ltd. Lanzhou730000 China

While two-dimensional lamellar materials, specifically Ti3C2Tx MXenes, have shown great promise as wave-absorbing materials, the precise design of interlayer spacing poses a persistent challenge. In this study, Ti3C2 layers with adjustable interlayer spacings were crafted using a straightforward molecular welding technique. Through the incorporation of Ni nanoparticles onto the Ti3C2 layers using a combination of simple mechanical stirring and carbonation reactions, we successfully developed MXene@Ni composites featuring a distinct lamellar structure. A uniform dispersion of Ni nanoparticles on the surface of the Ti3C2 nanosheets was found with some of the nanoparticles intercalated into the layers. The MXene@Ni composites exhibited a maximum reflection loss (RL) value of −42.3 dB at 12.3 GHz, accompanied by an impressive effective absorption bandwidth (EAB) of 5.6 GHz. This outstanding absorption performance could be attributed to various factors, including the dielectric loss of the Ti3C2 lamellae, reflections and scattering of multiphase heterostructures, the magnetic loss of the Ni nanoparticles, and their synergistic attenuation. Furthermore, Ni nanoparticles with high electrical conductivity induced vortex currents under the alternating influence of electromagnetic waves (EMWs), resulting in a substantial depletion. This study introduces an innovative approach for synthesizing MXene@Ni composites with tunable interlayer spacing, showing their potential for applications in microwave absorption (MA). © 2024, The Authors. All rights reserved.

关键词： Welding

Computational screening of O‐functional MXenes for electrocatalytic ammonia synthesis

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2022年第7期43卷 1860-1869页

作者： Yijing Gao Shijie Zhang Xiang Sun Wei Zhao Han Zhuo Guilin Zhuang Shibin Wang Zihao Yao Shengwei Deng Xing Zhong Zhongzhe Wei Jian‐guo Wang Zhejiang Engineering Laboratory for Green Syntheses and Applications of Fluorine‐Containing Specialty Chemicals Institute of Advanced Fluorine‐Containing MaterialsZhejiang Normal UniversityJinhua 321004ZhejiangChina Institute of Industrial Catalysis College of Chemical EngineeringState Key Laboratory Breeding Base of Green‐Chemical Synthesis TechnologyZhejiang University of TechnologyHangzhou 310032ZhejiangChina Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Institute of Physical ChemistryZhejiang Normal UniversityJinhua 321004ZhejiangChina

The nitrogen reduction reaction(NRR)using new and efficient electrocatalysts is a promising al‐ternative to the traditional Haber‐Bosch ***,it remains a challenge to design efficient catalysts with improved catalytic ***,various O‐functional MXenes were investigated as NRR catalysts by a combination of density functional theory calculations and least absolute shrinkage and selection operator(LASSO)***_(3)C_(2)O_(X) has been regarded as a promising catalyst for the NRR because of its stability,activity,and *** poten‐tial‐determining step is*NH_(2) hydrogenation to*NH3 with a limiting potential of-0.45 ***‐more,via LASSO regression,the descriptors and equations fitting the relationship between the properties of O‐functional MXenes and NRR activity have been *** work not only pro‐vides a rational design strategy for catalysts but also provides machine learning data for further investigation.

关键词： Electrocatalytic ammonia synthesis O‐functional MXenes Density functional theory Least absolute shrinkage and selection operator regression Gibbs free energy

Programmable Ceramic 4d Printing Via Multi-Material Vat Photopolymerization

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Zhao, Pengcheng Hu, Kehui Wang, Qing Lu, Zhigang State Key Laboratory of Tribology in Advanced Equipment Tsinghua University Beijing100084 China Department of Mechanical Engineering Tsinghua University Beijing100084 China Tsinghua University China Key Laboratory of Advanced Materials Processing Technology Ministry of Education Tsinghua University Beijing100084 China State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Tsinghua University Beijing100084 China

Based on conventional 3D printing, 4D printing enables self-deformation of materials in the time dimension, thus greatly improving the forming capacity for complex structures. However, compared with soft materials such as polymers, ceramics are difficult to 4D print owing to their brittle and stiff properties. Here, by combining multi-material vat photopolymerization and a one-step shape/material transformation at high temperature, we develop a ceramic 4D printing technology with significant geometrical flexibility. The self-deformation during sintering is induced by shrinkage mismatch, which is attributed to the generation of a dense Al2O3-SiO2 mixed area under the fused SiO2 infiltration. In addition, self-deformation can be controlled by programming the SiO2 pattern on the Al2O3 substrate. Finally, through a series of complex 4D printed structures from "line" to "plane", the excellent forming ability of this technology is demonstrated. This research on ceramic 4D printing is expected to broaden the applications of aerospace components, electronic devices, and high-temperature microelectromechanical systems. © 2024, The Authors. All rights reserved.

关键词： Silica