CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xiao-Hui Yang,Yu Wang,Guo-Hua Zhang,Kuo-Chih Chou
Tungsten and molybdenum borides are widely used in ultra-high temperature ceramics (UHTCs) and electrode material. In this research, ultra-fine and ultra-coarse binary borides (WB, W 2 B 5 , MoB, Mo 2 B 5 ) and MoAlB powders were prepared with W/Mo and B 4 C as raw materials and Ca/Al as the decarbonization agent. The feasibility of using Ca and Al as decarburizing agents was assessed by thermodynamic calculations. Meanwhile, the effects of reaction temperature, decarbonization agent type and its additional amount on the phase, morphology and size distribution of the powder products were thoroughly investigated. The results revealed that single phase products with carbon content of less than 1 wt% could be prepared. Moreover, the morphology and particle size of products were significantly affected by the reaction temperature and type of decarburization agent. When using Ca as the decarburizing agent, ultra-fine WB and MoB powders were effectively prepared, probably owing to the fact that W/Mo are essentially insoluble in Ca melt. However, the great solubility of W/Mo in Al makes it easily to synthesize ultra-coarse borides at high temperatures via the dissolution-precipitation mechanism. Additionally, ultra-fine borides particle can also be prepared by lowering the temperature and amount of Al to weak the dissolution-precipitation mechanism.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Xu Huang,Xuezhang Xiao,Xuancheng Wang,Zhendong Yao,Jiahuan He,Xiulin Fan,Lixin Chen
Li–Mg–B–H reactive hydride composite (RHC) has attracted extensive attention over the past decades for its extremely high hydrogen storage capacity (11.5 wt%). But the sluggish desorption kinetics for the second step dehydrogenation reaction need to be further improved. Herein, short rod-like TMTiO 3 (TM = Co, Ni) bimetallic oxides , which contain two kinds of transition metal elements, were synthesized and introduced into Li–Mg–B–H RHC for the first time. The NiTiO 3 exhibits excellent catalytic effect on the hydrogen desorption kinetic performance of Li–Mg–B–H RHC, and the incubation period for the second step dehydrogenation reaction is eliminated completely by reducing the apparent activation energy for the generation of MgB 2 from 296 kJ/mol to 269 kJ/mol. The NiTiO 3 doped Li–Mg–B–H RHC can desorb about 9.0 wt% H 2 without obvious attenuation of kinetic performance in five cycles. Mechanism analyses reveal that the in-situ generated nano-sized MgNi 3 B 2 and TiB 2 species (∼5 nm) both meet the critical value ( < 10%) of the edge-to-edge matching model (5.77% for MgNi 3 B 2 and 2.22% for TiB 2 ), which play a significant role in supporting the nucleation of MgB 2 . Meanwhile, the extremely fine MgNi 3 B 2 and TiB 2 heterogeneous nucleation sites can inhibit the excessive growth for a single crystal nucleus of MgB 2 . The heterogeneous nucleation and grain refinement mechanisms caused by the novel bimetallic oxide could provide alternative insights into designing an in-situ generated nano-sized catalytic hydrogen storage system with enhanced kinetics and cyclic stability for hydrogen-fueled applications.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Yu Wang,Guo-Hua Zhang,Xin-Bo He,Bai-Jun Yan
This paper provides a new method for preparing refractory metal diboride by reducing refractory metal oxide with Calcium hexaboride (CaB 6 ), which is prepared using B 4 C and calcium as raw materials. For refractory metal powders (M = Ti, Zr, Hf, V, Nb, Ta, Cr) which are expensive and hard to be produced by a simple route, it is more cost-effective to directly use refractory metal oxide to prepare its boride. After reacting at 1473 K for 4 h, CaB 6 and refractory metal oxide could completely react to form MB 2 , CaO and B 2 O 3 . The single-phase product with the particle size of sub-micron was obtained after acidic leaching, filtration and drying. CaB 6 could be used as a universal reducing agent to prepare metal boride.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 105
·期 3
·1954-1966
·
IF 3.784
Yu Wang,Kuo-Chih Chou,Guo-Hua Zhang
Due to strong anti-poisoning ability, good emission stability, high emission current density, lanthanum hexaboride (LaB 6 ) and cerium hexaboride (CeB 6 ) have been maturely applied in electron emission emitter. In this paper, a new manufacturing method for LaB 6 (or CeB 6 ) powder was proposed by using La 2 O 3 (or CeO 2 ), B 4 C, and Al as raw materials. After high-temperature reaction in the range of 1673–1773 K and the following alkaline leaching at 90°C, LaB 6 or CeB 6 powder with particle size of about 10 μm was obtained. Furthermore, by Al metal flux method, the obtained powder was used to manufacture single crystal block with size of several millimeters.
研究领域:
材料科学
·
电子发射材料
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Xinyu Zhu,Yang Li,Xuan Tian,Runde Wang,Shanshan Wang,Huining Wang,Jiemei Yu,Taizhong Huang
Transition metal borides have great potential to be low-cost, high-performance catalysts for novel energies despite the synthesis is rather difficult. In this paper, the reduced graphene oxide (rGO) supported iron boride (Fe 2 B/rGO) based catalysts are synthesized by a facile reduction method. The successful synthesis of Fe 2 B is confirmed by X-ray diffraction, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photo-electron spectroscopy (XPS) and other tests. HRTEM tests showed that the constructed Fe 2 B was embedded in the rGO, where B played the role of coordination atoms which could regulate the electronic structure of the catalysts and improve the catalytic performance towards oxygen reduction reaction (ORR). The electrochemistry tests showed that the peak current intensity of the Fe 2 B/rGO catalyzed ORR could be reached up to 7.6 mA/cm 2 , which surpassed that of the Pt/C (20 wt%) catalyst. The current intensity can be kept at 82.47% after continuous running 20,000 s, which is higher than the Pt/C catalyst (79.4%). The onset potential reaches up to 0.95 V, which is only 0.06 V lower than that of Pt/C (20 wt%) catalyst. Both RDE and RRDE tests confirmed that the Fe 2 B/rGO catalyzed ORR major happed through 4-electron pathway. The redistributed electron between iron and boron atoms promoted the happening of ORR on Fe 2 B/rGO catalysts. The results of this work provide a novel way to develop high performance transition metal boride based catalysts for ORR.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yu Wang,Zhi-Bo Li,Kai-Fei Wang,Guo-Hua Zhang
Tungsten borides are special compounds with potential applications in superhard materials, anti-friction materials, and catalytic materials. In this study, a new synthetic method for tungsten boride is proposed using tungsten (W) and boron carbide (B 4 C) as raw materials. First, the boronization reaction between W and B 4 C was carried out at a high temperature; then, the boronization products were reacted with calcium to generate CaC 2 for decarburization. After acidic leaching of the CaC 2 and Ca, pure tungsten boride could be prepared. By investigating the reaction between different ratios of W and B 4 C, it was found that only pure W 2 B and WB were synthesized in the current method, and W 2 B 5 could react rapidly with Ca to form WB and CaB 6 . However, in the absence of a decarburization treatment after the boronization process, carbon-containing WB (C content = 1.2 wt%) and W 2 B 5 (C content = 3.4 wt%) could also be prepared. In addition, it was concluded that the prepared tungsten boride roughly maintained the morphology and particle size of raw W, and ultra-fine tungsten boride could be synthesized with ultra-fine W powder at a low boronization reaction temperature.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 9
·3031
·
IF 3.748
Shijing Zhao,Wenju Zhou,Xiaojun Xiang,Xuyan Cao,Ning Chen,Weifeng Chen,Xiaohui Yu,Bingmin Yan,Huiyang Gou
The precise determination of atomic position of materials is critical for understanding the relationship between structure and properties, especially for compounds with light elements of boron and single or multiple transition metals. In this work, the single crystal X-ray diffraction is employed to analyze the atomic positions of Co2MoB4and Fe2MoB4with a Ta3B4-type structure, and it is found that the lengths of B-B bonds connecting the two zig-zag boron chains are 1.86 Å and 1.87 Å, but previously unreported 1.4 Å. Co and Fe atoms occupy the same crystallographic position in lattice for the doped samples and the valence is close to the metal itself, and Co/Fe K-edge X-ray Absorption Fine Structure(XAFS) spectra of borides with different ratios of Co to Fe are collected to detect the local environment and chemical valence of Co and Fe. Vickers hardness and nano indentation measurements are performed, together with the Density Functional Theory (DFT) calculations. Finally, Co2MoB4possess better thermal stability than Fe2MoB4evaluated by Thermogravimetric Differential Thermal Analysis (TG-DTA) results.Keywords:transition metal boride;hardness;XAFS;thermal stability
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 4
·2399-2406
·
IF 3.094
Yu Wang,He Zhang,Shuqiang Jiao,Kuo-Chih Chou,Guo-Hua Zhang
Molybdenum boride is an ideal hard and wear-resistant material. In this study, a new method is proposed for preparing molybdenum boride, by which Mo first reacts with B 4 C to generate the mixture of molybdenum boride and C, and then the product is decarburized by molten Ca to generate CaC 2 . Pure molybdenum boride could be obtained after acid leaching to remove the by-product CaC 2 . According to the experimental and thermodynamic calculation results, it is concluded that the single-phase MoB could be successfully prepared, while Mo 2 B, Mo 2 B 5 , and MoB 4 could not be synthesized by this method. Moreover, it was found that the particle size of finally prepared MoB is determined by particle size of raw Mo powder. The residual carbon content of the product could be decreased to 0.10 wt% after first reaction at 1673 K for 6 hours and then decarburization reaction at 1673 K for 6 hours.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Chao Gu,Xuefeng Zhou,Dejiang Ma,Yusheng Zhao,Shanmin Wang
Boron-rich tungsten borides such as WB2+x and WB3+x have been highly expected to be superhard with many advantages over conventional superhard materials. However, because the formation of boron-rich tungsten borides is thermodynamically unfavorable at ambient pressure, their crystal structures, compositions, and properties are largely unexplored, which have impeded the rational design of functional materials in the W–B family. In this work, using unique high-pressure reactions, we report a systematic synthesis study of challenging compounds of tungsten borides including WB, WB2+x, and WB3+x. The use of pressure, combined with the controllable temperature, heating duration, and ratios of starting reactants, leads to different compositions and structures of final products with largely tunable crystallite size from nanocrystalline to single-crystal forms. In addition, the optimal conditions for the formation of WB3+x are well investigated by tuning the temperature and starting ratio of reactants, as well as by adding a solvent material. Phase diagrams and stabilities of the involved W–B compounds are also well depicted, which would provide an important guidance for future exploratory synthesis and study of the family of transition-metal borides.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Shixin Zhao,Lei Zhuang,Hulei Yu,Yanhui Chu
High-entropy diboride (HEB) microfibers are in great demand for structural and functional applications in extreme conditions. Here, we synthesize (Hf, Ta, Nb, Mo, Ti)B 2 HEB microfibers through a two-step technique involving thermal decomposition of polymers and subsequent boro/carbothermal reduction for the first time. Specifically, polymer precursor microfibers are first decomposed at a moderate temperature of 773 K, followed by a high-temperature calcination at 2273 K to promote boro/carbothermal reduction. The resulting HEB microfibers, with a diameter of approximately 1 µm, exhibit a polycrystalline structure and high-compositional uniformity from nanoscale to microscale. This work opens up a new way to synthesize innovative HEB microfibers.
研究领域:
材料科学
·
陶瓷工程
·
纳米技术
·
无机合成
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yixiang Zhu,Rui Chen,Yixuan Yang,Yu Liu,Xuyu Wang,Hongbing Ji
The catalytic oxidation dehydrogenation of propane to propylene, achieved at low temperatures and with high selectivity on catalysts supported by non-noble metals, exhibits significant potential for a wide range of applications. The performance of boron-based catalysts in ODHP is remarkable; however, there is a dearth of research on their low-temperature range performance. The present study employed a straightforward impregnation method to synthesize a range of Mo/h-BN-γ-Al 2 O 3 catalysts with varying molybdenum loadings, focusing on the comparison between commercial h-BN and h-BN-γ-Al 2 O 3 mixed support. The Mo/h-BN-γ-Al 2 O 3 catalyst demonstrates remarkable low-temperature ODHP activity, with an initial conversion rate of 2.36 % and a propylene selectivity of 96 % at a reaction temperature of 260 ℃, exhibiting good stability over 50 h, the catalytic performance of Mo/h-BN-γ-Al 2 O 3 in the low-temperature range surpasses that of commercial h-BN by a significant margin. Comparative experiments, along with physical and chemical characterization techniques, demonstrate that the incorporation of an appropriate quantity of Mo enhances the catalyst's acidity and redox capability. Furthermore, the synergistic effect between MoO x and BO x promotes low-temperature ODHP. The mechanism underlying the catalyst's low-temperature reaction was investigated using in-situ infrared spectroscopy technology.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Yingxue Du,Qihao Wang,Xingchao Zang,Weiping Xiao,Yingxia Zong,Xuyun Guo,Zexing Wu,Lei Wang
The development of efficient and durable bifunctional electrocatalysts for overall water splitting remains a key challenge for sustainable hydrogen production. In this study, a novel strategy is proposed to synergistically design boron vacancies and integrate Ru species into NbB 2 (Ru/RuO 2 -NbB 2 -v) by calcination and immersion methods. NbB 2 with its intrinsic high conductivity facilitates to electron transport and improves the reaction kinetics of the catalyst. The strategic introduction of abundant B vacancy and Ru species can expose numerous active sites and lower the reaction energy barriers in the materials, thereby enhancing the reactivity of the catalysts. Impressively, Ru/RuO 2 -NbB 2 -v exhibited superior hydrogen evolution reaction (HER) activity in wide pH range. In addition, Ru/RuO 2 -NbB 2 -v also exhibits good oxygen evolution reaction (OER) performance in acidic and alkaline. A self-assembled electrolyzer driven by simulated solar energy enables the conversion of solar energy into hydrogen energy. The work pioneers a defect-engineering and noble-metal-decoration strategy to transform metal borides into versatile electrocatalysts, offering a scalable pathway for clean energy technologies.
研究领域:
材料科学
·
能源技术
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）