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1. chinaXiv:202008.00083 [pdf]

Delocalized Electrochemical Exfoliation toward High-throughput Fabrication of High-quality Graphene

Penglei Zhang; Peng Heng; Qingkai Yu; Gang Wang; Tao Huang; Siwei Yang; Xiaosong Liu; Zhi Liu; Xiaoming Xie; Guqiao Ding
Subjects: Materials Science >> Materials Science (General)

Graphene has well demonstrated its unique properties and advantageous performances in lots of fields during the last 16 years. However, its industrial applications are still impeded by inefficient mass fabrication of high-quality graphene because of the great challenge in deep yet non-destructive graphite exfoliation. Herein, we demonstrated a delocalized electrochemical exfoliation (DEE) technique to efficiently fabricate high-quality graphene. Importantly, chemically transmitting the electric potentials was firstly proposed to spatially extend the exfoliation capability of electric potentials and electrochemically exfoliate every graphite particle dispersed in the electrolyte. The resulting graphene possesses ultralow defect density (ID/IG~0.07) and extremely high carbon-to-oxygen ratio (~28). Remarkably, high yields (~98.4%, 1-10 layers) and record high production rates (~72.7 g h?1) are realized in up-scaled batch of DEE. Further mechanism investigation revealed that the exfoliation capability of the electric potentials was transmitted to the whole electrolyte system by a dynamically favorable pathway. This pathway includes electrochemical oxidation, intercalation and interlayer bubble generation reactions, which makes deep and non-destructive exfoliation possible for every dispersed graphite particle in a scalable and reproducible manner. This way of using electric potentials differs from existing electrochemical methods and guarantees high throughput as well as high quality. The strategy of delocalized electrochemical exfoliation and the underlying concept of chemically transmitting the electric potentials would accelerate the commercialization of graphene and inspire more efficient fabrication of two-dimensional materials.

submitted time 2020-08-12 Hits10751Downloads1395 Comment 0

2. chinaXiv:202001.00046 [pdf]

A general self-consistent framework for studying cumulative displacement damage in nanostructured metals based on parameter passing and structural feedback between atomic and coarse-grained techniques

Xiangyan Li; Yange Zhang; Yichun Xu; Xuebang Wu; Xianping Wang; B.C. Pan; C.S. Liu; Q.F. Fang; Jun-Ling Chen; G.-N. Luo; Zhiguang Wang; X. Liu
Subjects: Materials Science >> Materials Science (General)

Nano-crystalline metals (NCs) exhibit radiation-tolerance due to the sink of grain boundaries (GBs) for radiation-induced defects such as self-interstitial atoms (SIAs) and vacancies (Vs). However, the relevant mechanisms for the radiation damage accumulation and GB structural relaxation under high radiation field in NCs are still not well understood due to the lack of self-consistent across-scale techniques for simulating radiation-induced microstructures evolution. In this article, by combining coarse-grained and atomistic simulations, we proposed a coupling method to investigate the evolution of the microstructure and SIA/V-GB interaction under cumulative irradiation in NC iron. The SIA overloaded effect was revealed in iron GBs at a high radiation dose rate and/or low temperature. Two types of GB structural response were observed to cumulative irradiation. With the SIA accumulated at the GB, the new GB phase formed and then a critical concentration of the SIA at the GB transited to the small quantity of the V during the GB structural recovery, accompanied by the local GB motion. Consequently, the GB’s role for Vs nearby alternated between the trapping and annihilation center with radiation dose. Alternatively, GB developed to a disordered structure after trapping abundant SIAs. The GB response pattern to cumulative irradiation that is related to the SIA formation energy at the GB or the GB thermal stability is well manifested in the cumulative distribution function of the defects formation energy and its energy level density. The present work reveals the dynamic healing picture for radiation damage near the GB under cumulative irradiation.

submitted time 2020-01-07 Hits24145Downloads1496 Comment 0

3. chinaXiv:201809.00002 [pdf]

Pressure-Induced Indirect-Direct Bandgap Crossover and Bandgap Engineering in Ductile Semiconductor Ag3PO4 with Negative Linear Compressibility

Lu, Yang; Zhu, Shengcai; Huang, Eugene; He, Yu; Ruan, Jiaji; Yan, Hao
Subjects: Materials Science >> Materials Science (General)

Silver orthophosphate (Ag3PO4) has aroused widespread interest since the discovery of visible-light-driven photocatalysis activity. However, its indirect bandgap nature at ambient becomes an obstacle to improve the photocatalysis efficiency and use in other application fields. In this study, the indirect-to-direct bandgap crossover was found during the pressure-induced phase transition from cubic to trigonal phase in Ag3PO4. The observed bandgap narrowing could be partially retained after pressure was released to ambient conditions, accelerating to efficiently utilize the solar spectrum. Moreover, Ag3PO4 was ductile like metals. Unexpectedly, this ion-conducting and ductile semiconductor photocatalyst further exhibited the negative linear compressibility (NLC) at pressure range of 7.5-25 GPa. This work, combining experimental and theoretical tools, provides an insight into the modulation mechanism of the electronic structure for silver-based semiconductors, and may broaden the applications of Ag3PO4.

submitted time 2018-09-03 Hits21928Downloads2049 Comment 1

4. chinaXiv:201711.02640 [pdf]


刁加加,; 常春蕊,; 张志明,; 张好强,; 孙红婵,; 安立宝
Subjects: Materials Science >> Materials Science (General)


submitted time 2017-11-21 From cooperative journals:《材料研究学报》 Hits45550Downloads2457 Comment 0

5. chinaXiv:201711.02643 [pdf]


赵思勰,; 晏华,; 李云涛,; 汪宏涛,; 胡志德
Subjects: Materials Science >> Materials Science (General)


submitted time 2017-11-21 From cooperative journals:《材料研究学报》 Hits45662Downloads2360 Comment 0

6. chinaXiv:201711.02644 [pdf]


侯书亮,; 卢慧宫,; 顾逸凡,; 马小亮,; 吴一楠,; 王颖,; 李风亭
Subjects: Materials Science >> Materials Science (General)

以氧化铝、氢氧化铝、勃姆石为水不溶性金属源,用水热法合成了金属有机骨架MIL-53(Al)。使用SEM、XRD、氮气吸附和TGA表征了产物的形貌和结构,并与用传统水溶性硝酸铝合成的MIL-53(Al)对比。结果表明:使用三种水不溶性金属源都能合成典型的金属有机骨架材料MIL-53(Al)。用水热法制备的MIL-53(Al)产物的BET比表面积都在700~1000 m2/g。结果还表明,使用三种水不溶性金属源合成的MIL-53(Al)骨架的柔性(flexibility)与用常规铝硝酸盐合成的MIL-53(Al)不同。使用氧化铝合成的MIL-53(Al)常温下的孔道主要呈现大孔(lp)结构且骨架刚性较强。与使用其他铝源合成的MIL-53(Al)相比,用氧化铝合成的MIL-53(Al)对洛克沙胂有较好的吸附去除效果,吸附过程符合二级动力学模型。

submitted time 2017-11-21 From cooperative journals:《材料研究学报》 Hits42444Downloads2340 Comment 0

7. chinaXiv:201711.02646 [pdf]


卢秋影,; 姜宏伟
Subjects: Materials Science >> Materials Science (General)

在聚氧化丙烯多元醇(PPG)和二苯基甲烷二异氰酸酯(MDI)组成的交联聚氨酯(CPU)体系的基础上添加聚醚改性MQ树脂(E-MQ),制备出E-MQ树脂增强的浇注型聚氨酯弹性体。结果表明:E-MQ树脂与CPU有良好的相容性,制备出的E-MQ增强弹性体具有良好的力学性能。当E-MQ树脂用量为8%(E-MQ树脂占聚氨酯弹性体总质量分数)时增强聚氨酯弹性体的拉伸强度可达20.8 MPa,比CPU基础样提高22.4%,撕裂强度为82 kNm-1,邵尔A硬度为82度。

submitted time 2017-11-21 From cooperative journals:《材料研究学报》 Hits43213Downloads2132 Comment 0

8. chinaXiv:201711.02645 [pdf]


应彩虹,; 陈立佳,; 刘天龙,; 郭连权
Subjects: Materials Science >> Materials Science (General)


submitted time 2017-11-21 From cooperative journals:《材料研究学报》 Hits43304Downloads2098 Comment 0

9. chinaXiv:201711.02439 [pdf]


刘葛亮; 马冰洋; 尚海龙; 陈凡; 李荣斌; 李戈扬
Subjects: Materials Science >> Materials Science (General)

研究了溅射Al对Si3N4的润湿作用和Al及Al-Ni合金薄膜钎料对Si3N4陶瓷的钎焊。结果表明,高能量溅射Al粒子的直接撞击可以实现Al对Si3N4的“润湿”,使Al和Al-Ni合金薄膜熔化后即可对Si3N4陶瓷进行钎焊。所获得接头的钎缝致密饱满,与陶瓷形成无反应过渡层的良好冶金结合,纯Al钎焊接头的剪切强度为106 MPa,Al-1.0 at.% Ni亚共晶钎焊接头的强度提高到148 MPa,Al-3.0 at.% Ni接头的强度因钎缝形成共晶组织而略有降低,为132 MPa。相对于以上各接头的剪切断裂均产生于钎缝之中,当溅射Al粒子因Ni层阻挡不能直接撞击Si3N4表面时,Al-1.0 at.% Ni薄膜钎料熔化后不能润湿Si3N4,所得接头的剪切断裂发生在钎缝与陶瓷的界面,强度也降低为81 MPa。

submitted time 2017-11-21 From cooperative journals:《金属学报》 Hits48149Downloads3950 Comment 0

10. chinaXiv:201711.02440 [pdf]


荣凤鸣; 王誉; 张霞
Subjects: Materials Science >> Materials Science (General)

应用锌盐与氨水以及单氰胺水溶液间配体交换反应,制备了氰胺锌(ZnNCN)颗粒。并通过在前驱体盐溶液中共混银盐,利用相同的配体交换反应过程,制备了氰胺银(Ag2NCN)/ZnNCN复合颗粒。利用XRD、SEM、红外光谱(FT-IR)和紫外-可见(UV-Vis)吸收光谱对光催化剂的结构进行表征。结果表明,单一ZnNCN为花瓣状颗粒,宽禁带半导体材料(Eg=4.66 eV)。Ag2NCN/ZnNCN复合颗粒形貌与单一ZnNCN和Ag2NCN相比较有很大变化,两种金属氰胺化物以弱的物理作用力结合形成异质结构,复合颗粒的光谱响应范围扩展至可见光区,禁带宽度Eg=2.05 eV。以罗丹明B为光催化降解对象,研究了ZnNCN、Ag2NCN/ZnNCN复合颗粒在氙灯激发下的光催化活性。与单一ZnNCN以及Ag2NCN、ZnNCN机械混合物相比,Ag2NCN/ZnNCN复合颗粒表现出增强的光催化性能,表现为一级反应动力学特征。

submitted time 2017-11-21 From cooperative journals:《金属学报》 Hits43633Downloads2297 Comment 0

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