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

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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

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Domain Evolution, Dielectric and Piezoelectric Response in Bent Freestanding PbTiO3 Ferroelectric Nanowires

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SSRN 2024年

作者： Zhou, Meng-Jun Peng, Kun Tan, Yueze Yang, Tiannan Chen, Long-Qing Nan, Ce-Wen State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center of Smart Materials and Devices School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China Department of Materials Science and Engineering Materials Research Institute The Pennsylvania State University University ParkPA16802 United States School of Mechanical Engineering Shanghai Jiao Tong University Shanghai200240 China School of Materials Science and Engineering State Key Lab of New Ceramics and Fine Processing Tsinghua University Beijing100084 China

Ferroelectric oxides with excellent flexibility are of significant practical and theoretical interests in recent studies. With most up-to-date research efforts, the effect of large bending on properties of nano-scale ferroelectric materials is still to be investigated. In this work, we elucidate the effect of bending angle on ferroelectric domain structures and material properties of bending PbTiO3 nanowires using phase-field simulations and thermodynamic modeling. We find non-monotonic dependencies of the coercive fields, dielectric responses and piezoelectric properties on the bending angle. A maximum enhancement of 462% and 226% in the dielectric constant and piezoelectric coefficient, respectively, is achieved at an 18° bending angle for the PbTiO3 nanowire with a radius of R = 10 nm and length L=100 nm, which is attributed to the formation of strong-response zones within the nanowire as illustrated by both the phase-field and thermodynamic analysis. The current work provides useful theoretical insights for the experimental explorations into ferroelectric functionalities of nanomaterials and potential applications of high-performance flexible ferroelectric-based nanodevices. © 2024, The Authors. All rights reserved.

关键词： Piezoelectricity

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Modulation of the Octahedral Structure and Potential Superconductivity of La3Ni2O7 through Strain Engineering

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arXiv 2024年

作者： Huo, Zihao Luo, Zhihui Zhang, Peng Yang, Aiqin Liu, Zhengtao Tao, Xiangru Zhang, Zihan Guo, Shumin Jiang, Qiwen Chen, Wenxuan Yao, Dao-Xin Duan, Defang Cui, Tian Key Laboratory of Material Simulation Methods & Software of Ministry of Education State Key Laboratory of Superhard Materials College of Physics Jilin University Changchun130012 China MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Advanced Functional Materials and Mesoscopic Physics School of Physics Xi’an Jiaotong University Xi’an710049 China Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat-Sen University Guangzhou510275 China Institute of High Pressure Physics School of Physical Science and Technology Ningbo University Ningbo315211 China

The recent transport measurement of La3Ni2O7 uncover a "right-triangle" shape of the superconducting dome in the pressure-temperature (P-T) phase diagram. Motivated by this, we perform theoretical first-principles studies of La3Ni2O7 with the pressure ranging from 0 to 100 GPa. Notably, we reveal a pressure dependence of the Ni-dz2 electron density at the Fermi energy (nzEF) that highly coincides with such shape. On this basis, we further explore the electronic structure under uniaxial stress. By tracking the stress response of nzEF , we propose that superconductivity can be achieved by applying only ~ 2 GPa of compression along the c axis. The idea is further exemplified from the perspectives of lattice distortion, band structure, Fermi surface and superconducting phase coherence. We also discuss the possible charge modulation under the stress and provide an insight to the relation between nzEF and the superconducting Tc in La3Ni2O7 system. Our study provides a helpful guide to the future experiment. © 2024, CC BY.

关键词： Band structure

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Directional transport for efficient catalysis

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Matter 2023年第3期6卷 674-676页

作者： Jie Ying Mark D. Symes Xiao-Yu Yang School of Chemical Engineering and Technology Sun Yat-sen University Zhuhai 519082 China WestCHEM School of Chemistry University of Glasgow University Avenue Glasgow G12 8QQ UK State Key Laboratory of Advanced Technology for Materials Synthesis and Processing & Shenzhen Research Institute & Joint Laboratory for Marine Advanced Materials in National Laboratory for Marine Science and Technology (Qingdao) Wuhan University of Technology Wuhan 430070 China School of Engineering and Applied Sciences Harvard University Cambridge MA 02138 USA

Directional transport is a common phenomenon in nature that underpins the efficient completion of a number of complex and elaborate processes. However, its application to the design of catalysts is challenging as a result of a lack of understanding of the basic design principles in operation. To this end, it has now been demonstrated that a porous covalent organic framework material with a mesoporous aperture substantially promotes the transport ability of oxygen and consequently increases the catalytic activity of commercial Pt/C catalysts in a fuel cell.

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Hierarchical porous nanofibers of carbon@nickel oxide nanoparticles derived from polymer/block copolymer system

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Chinese Chemical Letters 2020年第9期31卷 2202-2206页

作者： Wen Shang Huanzhou Du Yage Wu Jianlin Xu Fen Ran State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals School of Material Science and EngineeringLanzhou University of TechnologyLanzhou 730050China BaiYin Research Institute of Novel Materials Lanzhou University of TechnologyLanzhou 730050China

The triblock copolymer(PAA-b-PAN-b-PAA) iSs prepared by reversible addition-fragmentation chaintransfer polymerization,and then blended with polymer(PAN) and metal hydroxide(Ni(OH)2) as a precursor for heat-treatment.A composite material of hierarchical porous nanofibers and nickel oxide nanopa rticles(HPCF@NiO) is prepared by electrospinning combined with high-tempe rature *** effects of the ratio of PAA and PAA-b-PAN-b-PAA on the internal structure of nanofibers and their electrochemical properties as positive electrode materials are *** experimental results show that when the ratio of PAA to PAA-b-PAN-b-PAA is 1.3 to 0.4,it has good pore structure and excellent electrochemical *** the current density of 1 A/g,the specific capacitance is 188.7 F/g and the potential window is -1 V to 0.37 *** asymmetric supercapacitor assembled with activated carbon as the negative electrode materials has a specific capacitance of 21.2 F/g in 2 mol/L KOH and a capacitance retention of 85.7% after 12,500 cycles at different current density.

关键词： Electrospinning Block copolymer Nickel oxide Hierarchical porous carbon fiber Supercapacitors

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Ultra-Fine Grained Tungsten Heavy Alloy Prepared by High-Pressure Spark Plasma Sintering

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SSRN 2022年

作者： Zhang, Shuaihao Ji, Wei Zhu, Qiqi Li, Qiunan Wang, Weimin Fu, Zhengyi State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Hanjiang Hongyuan Xiangyang Silicon Carbide Special Ceramics Co. Ltd. Xiangyang441000 China

Tungsten heavy alloy (WHA) is an ideal material employed for kinetic energy penetrators due to its high density and excellent mechanical properties. However, it is difficult to obtain ultra-fine grained tungsten alloy with excellent properties by traditional powder metallurgy method because of severe grain growth at high sintering temperature with long soaking time. In this study, highly dense 93W-5.6Ni-1.4Fe (wt.%) WHA was successfully fabricated at low temperature of 950 °C with high pressure of 150 MPa by spark plasma sintering. The as-sintered tungsten alloy possesses high relative density (98.6%), ultra-fine grain size (271 nm) and high dislocation density (2.6×1016 m-2 ), which results in excellent properties such as high hardness (1079 HV1). © 2022, The Authors. All rights reserved.

关键词： Spark plasma sintering

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Machine Learning for Battery Research

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SSRN 2022年

作者： Zhao, Yan Wei, Zheng He, Qiu International School of Materials Science and Engineering State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei430070 China The Institute of Technological Sciences Wuhan University Wuhan Hubei430072 China

Batteries are vital energy storage carriers in industry and in our daily life. There is continued interest in the developments of batteries with excellent service performance and safety. Traditional trial-and-error experimental approaches have the limitations of high-cost and low-efficiency. Atomistic computational simulations are relatively expensive and take long time to screen massive materials. The rapid development of machine learning (ML) has brought innovations in many fields and has also changed the paradigm of the battery research. Numerous ML applications have emerged in the battery community, such as novel materials discovery, property prediction, and characterization. In this review, we introduced the workflow of ML, where the task, data, feature engineering, and evaluation were involved. Several typical ML models used in batteries were highlighted. In addition, we summarized the applications of ML for the discovery of novel materials, and for property and battery state prediction. The challenges for the application of ML in batteries were also discussed. © 2022, The Authors. All rights reserved.

关键词： Machine learning

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The Effects of Diatom Frustules Shapes and Purity on the Performance of Diatom-Based Lithium Ion Silicon Carbon Anode materials

SSRN

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SSRN 2022年

作者： Liu, Yuhang Ren, Zijie Zhou, Liang Jiang, Yuqian Gao, Huimin An, Qinyou Xu, Longhua School of Resources and Environmental Engineering Wuhan University of Technology Hubei Wuhan430070 China Key Laboratory of Hubei Province for Mineral Resources Processing Environment Wuhan430070 China State Key Laboratory of Environment-friendly Energy Materials Sichuan Mianyang621010 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Southwest University of Science and Technology China

Diatomite has been widely studied as a silicon source. Three kinds of diatomite with different diatom frustules or different purities were reduced to porous silicon. The porous silicon coated carbon was prepared into positive electrode materials for battery cycle performance test. The test results showed that the Si/C composites anode material obtained by the reduction of diatomite with high purity of SiO2 has a high initial capacity, 2491mAhg-1, while that with low SiO2 purity is only 1412mAhg-1. The capacity retention rate of Si/C material prepared by columnar diatomite structure is higher than that of discoid diatomite. The battery made of high purity diatomite with discoid diatom has serious attenuation after 40 cycles. It could only retain 1/10 of the initial capacity, while the attenuation of the battery prepared by cylindrical diatomite is much better. The reason was that the specific surface area of macro porous silicon was much smaller than that of mesoporous silicon and less lithium ions were consumed in the irreversible process of forming solid electrolyte membrane for the first time. It could also be known that an appropriate amount of impurities in porous silicon can effectively reduce the volume expansion of silicon during the battery charge and discharge. The main reason was that the impurities occupied the internal space to alleviate the volume expansion of silicon or the excess carbon was coated on the impurities. © 2022, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Local amorphization in boron carbide at finite temperature: Strategies toward improved ductility

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Physical Review B 2021年第13期104卷 134105-134105页

作者： Jun Li Qi An Lisheng Liu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Chemical and Materials Engineering University of Nevada-Reno Reno Nevada 89557 USA

Boron carbide (B4C) is superhard, but its engineering applications are limited by the abnormal brittle failure arising from amorphous shear band formation. Mitigating the local amorphization is essential to improve the ductility of B4C. Here, we carried out ab initio molecular dynamics (AIMD) simulations to examine the response of B4C to shear along two plausible slip systems (001)/[100] and (111)/[112¯] at finite temperature. We found that the icosahedra of B4C gradually deconstruct at finite temperature, resulting in local amorphization, thereby giving rise to a lower stress barrier than that of density functional theory simulations at zero temperature. The deconstruction of the icosahedral clusters arises from the interaction with the neighboring chains. The failure mechanism at the finite temperature suggested that the local amorphization can be suppressed by altering the structure of the 12-atom icosahedron and the 3-atom chain of B4C. To demonstrate this, we replaced the B11CP icosahedron in B4C with B12 icosahedron to form boron-rich boron carbide (B13C2) and then performed the same shear deformations. We found that local amorphization significantly decreases, which results from the modified icosahedral interaction. We also altered the 3-atom C-B-C chain to the 2-atom P-P chain and found that the accumulated shear stress can be released through icosahedral slipping, which is achieved by breaking the chains. The icosahedral slipping then prevents the destruction of icosahedra under shear deformations, expected to improve the ductility. Our results demonstrate two design strategies toward improved ductility of B4C: (1) boron enrichment can alleviate amorphous shear band formation in boron carbide, and (2) altering the 3-atom chain to a 2-atom chain and meanwhile decreasing the strength of the chain to make it less stable than the icosahedron cage may lead to an icosahedral-slipping-dominated mechanism, thereby avoiding icosahedral fracture.

关键词： material failure Mechanical & acoustical properties Phase transitions Shear deformation

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Effective Strengthening and Toughening in Zn-1mg Alloy with Bimodal Grain Structure Achieved by Conventional Extrusion

SSRN

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SSRN 2022年

作者： Li, Ruimin Ding, Yutian Zhang, Hongfei Lei, Jian Shen, Yue State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology Lanzhou730050 China School of Materials Science and Engineering Lanzhou University of Technology Lanzhou730050 China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology School of Material Science and Engineering Lanzhou University of Technology No.287 langongping Road Qilihe district Lanzhou China

To better solve the problem that the inadequate mechanical performance of pure Zn and its as-cast alloys restricted the further clinical implant applications owing to its coarse grain size and HCP structure, some attempts at microstructure manipulation have been made by researchers. Interestingly, architecting heterogeneous structures is a promising strategy for overcoming the trade-off between strength and ductility in metallic materials. Herein, we reported a simple extrusion pathway for fabricating Zn-1Mg alloy with bimodal structure. Results revealed that the developed Zn alloy exhibited microstructural heterogeneities, including both bimodal grain structure and reforcement phase particles, which endowed the Zn-1Mg alloy with a satisfactory combination of yield strength (YS) of ~289 MPa, ultimate tensile strength (UTS) of ~320 MPa and fracture elongation (EL) of ~32%, superior to most Zn alloys reported so far. The strengthening-toughening mechanisms were systematically analyzed and the quantitative relationships between the yield strength and grain structure with a bimodal size distribution, as well as the second phase were established in this work. Additionally, the microstructure of the as-cast alloy consisted of the primary α- Zn dendrites and a three-component eutectic structure: α- Zn+Mg 2 Zn 11 +MgZn 2 . In as-extruded alloy, broken phase particles were effective sites for dynamic recrystallized (DRXed) grains nucleation via particle-stimulated nucleation (PSN) mechanism. This work would provide valuable insights for the design and production of high strength-ductility zinc alloys. © 2022, The Authors. All rights reserved.

关键词： Extrusion

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