Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 18
·8604-8611
·
IF 9.931
Yuyu Bu,Jun Ren,Huawei Zhang,Dongjiang Yang,Zhuoyuan Chen,Jin-Ping Ao
Point defects, such as oxygen vacancies in semiconductors, have been widely proven to influence the separation and transfer processes of the photogenerated hot charges. Besides point defects, to date, scarcely any study has focused on expounding the functions of line defects (such as dislocations) in the crystal of semiconductor photoanodes and influencing the photogenerated hot charge separation process. Herein, a nanoflower (NF)-like WO3 single-crystal thin film photoanode with edge dislocations is reported. The dislocation induces mismatch of the (002) and (020) facets. Further photoelectrochemical (PEC) performance and DOS calculation results indicate that a heterojunction system could be formed along the edge dislocations due to the energy difference between the mismatched (002) and (020) facets. Therefore, this present study provides an understanding of the line defect in the photogenerated hot carrier separation process and a novel method to improve the properties of photoelectrodes and photocatalytic materials in the near future.
研究领域:
材料科学
·
光电化学
·
纳米材料
·
半导体物理
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·
IF 3.5
Yingying Zeng,Hao Liang,Jieru Pu,Lei Liu,Xiaolong Pan,Hao Luo,Zhenwei Niu,Wei Zhang,Liang Bian
Tungsten disilicide (WSi 2 ) is a promising material for high-temperature applications due to its excellent mechanical properties and superior thermal stability. This study aims to investigate the mechanisms underlying the performance enhancement of polycrystalline WSi 2 and tungsten silicide (W-Si) composites synthesized by high-temperature and high-pressure (HPHT) strategies, focusing on their phase composition and microstructure. The results show that high pressure can effectively reduce the synthesis temperature of the tungsten silicide system, with the phase composition and microstructure of the products being dominated by the treatment temperature. The high intergranular strain resulting from the reactive process and the HPHT environment facilitated the formation of high-density dislocations, including dislocation arrays and networks with multiple orientations, especially near the grain boundaries. Additionally, a 3-nm thick amorphous ribbons were identified between these boundaries. This microstructure, characterized by high-density dislocations and amorphous ribbons, confers exceptional mechanical properties and oxidation resistance. The differences in oxidation behavior between powder and bulk WSi 2 samples underscore the complex relationship between phase stability and material properties under varying processing conditions. These findings indicate that dislocations and amorphous ribbons can achieve in high-temperature ceramics with strong covalent bonding, which is essential for the design and synthesis of advanced W-Si-based ceramics.
研究领域:
材料科学
·
固体力学
✓ 已验证
产品关联
DOI
高影响因子
NATURE MATERIALS
·
2025
·
IF 38.5
Li Zhe,Wang Yueshuai,Liu Hui,Feng Yi,Du Xiwen,Xie Zhiheng,Zhou Jihan,Liu Yang,Song Yun,Wang Fei,Sui Manling,Lu Yue,Fang Fang,Sun Dalin
Precious metals such as Pt are favoured as catalysts for the hydrogen evolution reaction (HER) due to their excellent catalytic activity. However, the scarcity and high cost of precious metals have prompted researchers to explore cheaper alternatives such as Cu. Nevertheless, Cu shows poor catalytic performance due to weak binding with intermediates. Here the catalytic activity of pure Cu is activated via electroreduction-driven modification of the local structure, achieving a HER catalytic performance superior to commercial Pt/C catalysts for working current densities greater than 100 mA cm −2 in acid electrolyte. Activation involved two steps. First, polycrystalline Cu 2 O nanoparticles were prepared via pulsed laser ablation, resulting in grain boundaries within the Cu 2 O particles as observed using electron microscopy. Next, the Cu 2 O particles were electroreduced to pure Cu, inducing the formation of distorted nanotwins and edge dislocations. These local structures induce high lattice strain and decrease the Cu coordination number, enhancing the interaction between Cu and intermediates—as calculated using density functional theory—leading to the excellent catalytic activity and durability of the catalyst. Our observations show that low-cost pure Cu can be a promising HER catalyst for large-scale industrial applications.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Energy Materials
·
2024
·
IF 24.4
Zhanxiang Yin,He Zhang,Yaqiang Wang,Yi Wu,Youbo Xing,Xue Wang,Xufei Fang,Yuan Yu,Xin Guo
Dislocations as line defects in crystalline solids play a crucial role in controlling the mechanical and functional properties of materials. Yet, for functional ceramic oxides, it is very difficult to introduce dense dislocations because of the strong chemical bonds. In this work, the introduction of high-density dislocations is demonstrated by ultrahigh-pressure sintering into a typical ceramic oxide, BiCuSeO, for thermoelectric applications. The ultrahigh-pressure induces shear stresses that surpass the critical strength for dislocation nucleation, followed by dislocation glide and profuse multiplication, leading to a high dislocation density of ≈9.1 × 10 16 m −2 in Bi 0.96 Pb 0.04 CuSeO ceramic. These dislocations greatly suppress the phonon transport to reduce the lattice thermal conductivity, reaching 0.13 Wm −1 K −1 at 767 K and resulting in a record-high zT of 1.69 in this oxide thermoelectric ceramic. This study demonstrates the feasibility of generating dense dislocations in ceramic oxides via ultrahigh-pressure sintering for tuning functional properties.
研究领域:
材料科学
·
物理学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Xingzhan Yuan,Shi Hong,Jing Wang,Bing Ma,Yifan Zhang,Man Niu,Laima Luo,Yucheng Wu
In this study, we propose a model to evaluate the ductile-to-brittle transition (DBT) of W based alloy using small tensile test and dislocation density measurement. The new model is built upon the high correlation between the DBT and the dislocation multiplication. Compared the measured results from the typical testing methods such as small tensile test, three-point bending test, it reveals that the new model is close to the bending test results. Interestingly, the equivalent transition temperature (ETT) of W-Y 2 O 3 alloy measured by three-point bending test and the new model is lower than that of pure W. The effect of grain boundary and Y 2 O 3 particles on DBT were discussed, and the lower transition temperature of W-Y 2 O 3 alloy is attributed to the easier dislocation multiplication near grain boundary as well as the increase of small angle grain boundary.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
·
2023
·
IF 9.4
Xudong Rong,Dongdong Zhao,Xiaofeng Chen,Xiang Zhang,Di Wan,Chunsheng Shi,Chunnian He,Naiqin Zhao
Dense intragranular distribution of nanoscale reinforcements is highly desirable since it is effective in reconciling the strength-ductility trade-off in Al matrix composites (AMCs). Herein, we report a systematic investigation on the work hardening and strain delocalization in Al-5 wt.% CuO (Al-5CuO) composite with strength-ductility synergy contributed by in-situ dense intragranular nanoscale Al 2 O 3 . Results reveal that Al-5CuO exhibits prominent hetero-deformation induced (HDI) strengthening as indicated by its larger HDI stress than effective stress. We showcase that the notable pile-ups of geometrically necessary dislocations (GNDs) at intragranular Al 2 O 3 result in the prevailing kinematic hardening. While the plastic relaxation dislocations (PRDs) around Al 2 O 3 generated by the release of GND-induced internal stress produce isotropic hardening. Both contribute to the pronounced work hardening of Al-5CuO. Comprehensive characterizations suggest the GND distribution with marked intragranular feature in Al-5CuO during straining, which implies the effective provoking of grain interior rather than grain boundary (GB)/interfacial zone to take plastic strain. On basis of the well-described storage and annihilation of GNDs and PRDs at the intragranular Al 2 O 3 , the microstructure-based strain-hardening model enables an in-depth understanding of the kinematic and isotropic hardening contributions by Al 2 O 3 in Al-5CuO. Systematic analysis further confirms the important roles of intragranular Al 2 O 3 in improving the strain partitioning, strain/stress transfer and strength matching across different domains of Al-5CuO, which significantly contributes to strain delocalization and hence strength-ductility synergy. This work sheds important insights on the innovative design of strong and ductile AMCs with intragranular nanoscale reinforcements for structural applications.
研究领域:
材料科学
·
机械工程
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Letters
·
2024
·
IF 8.6
Yang Zhao,Xiaobin Lin,Xudong Rong,Xiang Zhang,Dongdong Zhao,Chunnian He,Naiqin Zhao
Aluminum matrix composites (AMCs) reinforced with intragranular nano-sized Al2O3 were used as model material to investigate the effects of intragranular nano reinforcement on the mechanical properties at macro- and meso- levels. The results revealed that intragranular Al2O3 effectively facilitates the dislocation multiplication, which in turn enables the grain interior to endure high levels of plastic strain and consequently alleviates stress concentration at the grain boundary. Furthermore, intragranular Al2O3 leads to a collective enhancement in the intrinsic mechanical properties across domains of varying sizes, thereby contributing to the coordinated plastic deformation of heterogeneous grains, and enhancing the creep resistance of composite.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 17
·11596-11603
·
IF 3.442
Shen Hongxia,Nan Ruihua,Jian Zengyun,Li Xiaojuan
Perovskite MAPbBr 3 (MA = CH 3 NH 3 + ) single crystals were grown via the anti-solvent vapor-assisted crystallization method. The crystal growth process was optimized by adjusting the solution concentration and diluting the anti-solvent. The maximum size of the obtained crystal was 9 × 9 × 3 mm 3 . It shows that the MAPbBr 3 single crystal is a cubic structure, the space group is Pm \( \bar{3} \) m , and the lattice constant is 0.59062 nm. Furthermore, its energy band gap is approximately 2.23 eV. The atomic force microscopy results demonstrated that the growth process of MAPbBr 3 single crystal followed the defect step growth mechanism, which was controlled by the screw dislocations within the crystal. Based on the curling growth of a screw dislocation on the crystal surface, a spiral step was formed. After the step was rotated around the entire mesa, a higher step was generated. Repeatedly, the step growth of screw dislocation within the crystal came into being. Besides, some small pits were also observed on (100) plane of the MAPbBr 3 crystal. These pits hindered the movement of steps and affected the lattice arrangement around them, causing the structural mismatch and more defects within the crystals.
研究领域:
材料科学
·
晶体学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Guoqing Wang,Pengxing Cui,Gang Qin,Longfei Jiang,Fengjun Zhang,Xiaobing Zhou
In this study, a purity of up to 98.36 wt. % GdB 6 with screw dislocation growth morphology were successfully fabricated using an in-situ reaction approach. The terraced-like structure of the GdB 6 enhanced the interfacial polarization and multiple interface scattering of the electromagnetic waves. As a result, the as-obtained high purity GdB 6 powder presented superior electromagnetic wave absorption performance. The minimum reflection loss value can be −49.24 dB at the frequency of 13.12 GHz with a thin matching thickness of 1.44 mm. In addition, the widest effective absorption bandwidth can be up to ∼4 GHz (14–18 GHz) with a thin matching thickness of 1.25 mm. The remarkable electromagnetic wave absorption performance of GdB 6 ceramics could be attributed to conductance loss and polarization loss enhanced by the screw dislocation growth defects, as well as synergistic effects with magnetic loss. The as-obtained GdB 6 with synergistic dielectric loss and magnetic loss is to be a novel single-phase with excellent electromagnetic wave absorbing material, which will pave the way on the investigation of rare earth hexaborides for the ultra-high temperature environment applications.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2022
·Vol. 51
·期 9
·4846-4854
·
IF 2.047
Bo Lin,Wang Lei,Hou Yangbo,Li Fujin,Liu Sida,Zhang Ruipeng,Zuo Min,Zhao Degang
Ternary Cu 3 SbSe 4 thermoelectric material with a diamond-like structure exhibits good thermoelectric performance in the middle-temperature region. In this study, Cu 2.98 Co 0.02 SbSe 4 material with intrinsically low thermal conductivity was prepared by a melting–ball milling–hot pressing process. The maximum zT value for the Cu 2.98 Co 0.02 SbSe 4 sample was 0.7 at 650 K, which was about 190% higher than that of the pristine sample. The improvement in thermoelectric performance was ascribed to the realization of multi-scale features induced by ball milling. It was found that multiple scattering centers of phonons were formed via interfacial engineering, including dislocations, nano-holes and grain boundaries, which offers an applicable pathway for the reduction of lattice thermal conductivity. Graphical
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
能源材料
·
半导体物理
✓ 已验证
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2022
·
IF 11.322
Kan Liu,Yishi Su,Xiaozhen Wang,Yunpeng Cai,He Cao,Qiubao Ouyang,Di Zhang
The incorporation of micro- and nano-sized SiC particles (micro- & nano-SiCps) into Al matrix constituted the micro- & nano-SiCp/Al composites through powder metallurgy . A unique ultrafine-grained (UFG) microstructure with micro-SiCps distributed among Al grains and most of nano-SiCps dispersed in grain interiors is characterized. Based on this, the synergetic constraint of dual-scale reinforcements on deformation of Al matrix is employed to enhance dislocation accumulation through increased SiCp/Al interface area and Orowan pinning effect, resulting in an improved strain hardening capacity. Compared with 10 vol% micro-SiCp/Al composites, the composites with 1 vol% nano-SiCps and 9 vol% micro-SiCps exhibit notable tensile properties of 285 MPa in yield strength , 374.7 MPa in ultimate strength and 11.3% in total elongation, increased by 32.6%, 28.7% and 37.8%, respectively, while remain a comparable Young's modulus of 94.6 GPa. Theoretical analysis proves that the dominant strengthening mechanism in micro- & nano-SiCp/Al composites is dislocation strengthening, different from the load transfer in individual micro-SiCp/Al composites. Our work provides inspirations for fabricating high-modulus Al matrix composites with simultaneously enhanced strength and ductility.
研究领域:
材料科学
·
力学
✓ 已验证
DOI
高影响因子
Small
·
2023
·Vol. 19
·期 15
·2206404
·
IF 13.3
Jialin Zhang,Yuan Ji,Huating Liu,Ningyan Cheng,Siqi Guo,Ming Yang,Long Ren,Binghui Ge
Atomic understanding of a chemical reaction can realize the programmable design and synthesis of desired products with specific compositions and structures. Through directly monitoring the phase transition and tracking the dynamic evolution of atoms in a chemical reaction, in situ transmission electron microscopy (TEM) techniques offer the feasibility of revealing the reaction kinetics at the atomic level. Nevertheless, such investigation is quite challenging, especially for reactions involving multi-phase and complex interfaces, such as the widely adopted carbothermal reduction (CTR) reactions. Herein, in-situ TEM is applied to monitor the CTR of Co 3 O 4 nanocubes on reduced graphene oxide nanosheets. Together with the first-principle calculation, the migration route of Co atoms during the phase transition of the CTR reaction is revealed. Meanwhile, the interfacial edge-dislocations/stress-gradient is identified as a result of the atomistic diffusion, which in turn can affect the morphology variation of the reactants. Accordingly, controllable synthesis of Co-based nanostructure with a desirable phase and structure has been achieved. This work not only provides atomic kinetic insight into CTR reactions but also offers a novel strategy for the design and synthesis of functional nanostructures for emerging energy technologies.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）