CATALYSIS TODAY
·
2018
·
IF 4.667
Lingcong Li,Xiaojun Liu,Hong He,Ningqiang Zhang,Ziwen Liu,Guizhen Zhang
The MgO-doped hexagonal boron nitride (MgO-h-BN) nanomaterials were designed as a support for Palladium (Pd) catalysts for CO oxidation reaction. The catalytic properties of Pd/MgO(5)-h-BN catalyst was investigated and compared with Pd/h-BN catalyst. Transmission electron microscopy (TEM) results suggested that the PdO nanoparticles with small grain sizes (ca. 8 nm) were effectively dispersed on the surface of MgO, and the MgO were deposited on the h-BN nanosheets in the Pd/MgO(5)-h-BN catalyst. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed that a small amount of Mg 2+ embedded into the B vacancies of h-BN nanosheets in the Pd/MgO(5)-h-BN catalyst. More significantly, a large amount of adsorbed oxygen appeared near the B vacancies of Pd/MgO(5)-h-BN catalyst. The experiments outcomes of diffuse reflectance fourier transform spectra analysis of CO (CO-DRIFT) indicated that the carbonate/formate species were easily decomposed to CO 2 on the Pd/MgO(5)-h-BN catalyst than Pd/h-BN catalyst, which might be a reason why the Pd/MgO(5)-h-BN catalyst had high CO oxidation activity. According to above analyses, we provide a new insight for the MgO-h-BN nanomaterials for Pd catalysts for application in CO oxidation reaction.
研究领域:
催化
·
材料科学
·
化学
·
纳米技术
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DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Ziyi Li,Li Huang,Xiaoyang Yu,Kun Huang,Wenbo Cui,Hong Zhang
The development of stable and efficient ODS catalysts for achieving room-temperature catalytic oxidation desulfurization is one of the challenges in the field of catalytic oxidation desulfurization. This work successfully synthesized and evaluated a new type of composite catalyst, Mo8/h-BN, using the wet impregnation method to investigate its desulfurization performance under various conditions. ODS tests were conducted on DBT, BT, and 4,6-DMDBT using Mo8/h-BN as the catalyst, H2O2 as the oxidant, and [BMIM]PF6 as the extractant. Characterization and testing revealed that Mo8/h-BN exhibited excellent ODS activity, converting DBT completely at 60 °C in 10 min. This study not only explored the optimal desulfurization conditions but also investigated the desulfurization performance of the catalyst at room temperature. Additionally, it is speculated that there may be an electron transfer between Mo8 and h-BN, which enhances the stability of the catalyst. Finally, possible CODS mechanisms were inferred through GC-MS and free radical trapping experiments. In conclusion, the composite catalyst Mo8/h-BN provides a new pathway for developing low-energy consumption, sustainable, cost-effective, and efficient desulfurization catalysts.
研究领域:
催化化学
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能源化学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Shuquan Yang,Lan Zhang,Meihui Xiao,Lin Chen,Jun Sun,Jianjun Ding,Xiaoxiao Li,Yi Gong,Kang Zheng,Xian Zhang,Xingyou Tian
Microwave devices with reduced dielectric loss and electronic components with increased integration density necessitate the higher performance of electronic packaging materials. The h-BN/AlN/CaCO 3 -MgO-B 2 O 3 -SiO 2 -Li 2 CO 3 glass composites were prepared via tape-casting and then sintered by pressureless and hot-pressing, respectively. The thermal conductivity of pressureless sintered composite was increased to 6.55 W/(m·K) by incorporating 3 wt% h-BN, and the thermal expansion of 4.47 ppm/K was achieved along with low dielectric constant of 5.76 and dielectric loss of 7.02 × 10 −4 at 24 GHz. In contrast, the hot-pressing sintered composite containing 4 wt% h-BN exhibited higher thermal conductivity of 10.3 W/(m·K) and lower dielectric loss of 4.77 × 10 −4 . The microstructure characterization indicated the construction of heat conduction networks, and XRD analysis illustrated the formation of crystallization in the glass. Such low-temperature co-fired ceramic (LTCC) with high thermal conductivity and low dielectric loss would be a promising candidate for electronic packaging and 5G communication applications.
研究领域:
材料科学
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电子工程
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陶瓷工程
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通信技术
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产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Zixuan Li,Dequan Bao,Wei Zhao,Wenxuan Xu,Yingheng Huang,Xiyong Chen,Hao Zhang,Xuhui Sun
Gel polymer electrolytes (GPEs) have emerged as a highly promising alternative to conventional liquid electrolytes for stable lithium-metal batteries (LIBs). However, their inherent poor mechanical properties and limited interfacial compatibility with lithium metal usually lead to unexpected growth of lithium dendrites , hindering commercial viability. Herein, an asymmetric polymer electrolyte with h-BN (HGPE) as protective layer was fabricated via a facile one-step coating strategy. Compared to pure GPE, the asymmetric polymer electrolytes exhibit significantly enhanced mechanical strength from 4.4 MPa to 7.4 MPa, effectively suppressing lithium dendrite growth. Furthermore, the HGPE improves interfacial compatibility with the anodes by preventing direct contact between GPE and lithium metals. The addition of h-BN also enhances the lithium-ion transfer number (t Li+ ), reaching 0.87 compared to 0.53 for pure GPE, attributed to the hindrance of anion movement by the protective layer. Consequently, the Li symmetric battery assembled with HGPE demonstrate exceptional long-term stability, maintaining performance over 1600 h at 0.1 mA cm −2 . Furthermore, the assembled Li|LiFePO 4 battery can deliver a high-capacity retention rate of 93.8 % after 500 cycles at room temperature, showcasing the promising potential of asymmetric polymer electrolytes for high-performance LMBs.
研究领域:
材料科学
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电化学
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能源存储
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DOI
高影响因子
POLYMER COMPOSITES
·
2022
·Vol. 43
·期 6
·3846-3857
·
IF 3.531
Wenhao Luo,Jinling Zeng,Yanrong Chen,Wenbin Dai,Yingbang Yao,Bing Luo,Fuzeng Zhang,Tingting Wang
Hexagonal boron nitride (h-BN) micro-platelets were surface-functionalized by sulfuric acid (SA). Such modified h-BN powders were mixed with thermoplastic polyether imide (PEI) to prepare flexible composite films using a solution casting method. After surface modification, the h-BN powders were uniformly dispersed in the PEI matrix. The thermal conductivity of the flexible composite materials was significantly improved, with a 60% increase over that of pure PEI. The mechanical properties of the composites were also measured and discussed. The Young's modulus of the h-BN/PEI composites was increased from 1.15 GPa for pure PEI to 1.62 GPa for the h-BN/PEI composite with a filling ratio 10 vol%. As compared to pure PEI film, the electrical breakdown strength of the composites with 5 vol% h-BN increased from 45.3 to 55.3 kV/mm. Our results show that the surface-modified h-BN filler is effective in improving the thermal conductivity and insulation performance of PEI-based composites.
研究领域:
材料科学
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热管理材料
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高分子复合材料
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2024
·
IF 5.1
Song Wu,Yongfeng Xia,Ming Zhu,Jun Zhao,Dongxu Yao,Yu-Ping Zeng
Si 3 N 4 ceramics now face new applications and challenges in the semiconductor field. The preparation of h-BN/Si 3 N 4 machinable ceramics incorporating 5–30 vol% h-BN via hot-pressing was carried out. This study systematically explored how the varying h-BN content influenced the composite's microstructure, mechanical attributes, and machinability . The results showed that some of the h-BN was encapsulated by growing Si 3 N 4 grains to form an intragranular structure during the process of hot-pressing, while the remaining h-BN exhibited uniform distribution along grain boundaries. The Si 3 N 4 phase transition in composites was inhibited by excessive h-BN, accompanied by a higher decrease in densification. The sample containing 20 vol% h-BN exhibited the best comprehensive performance, with high mechanical strength and excellent machinability. The bending strength and fracture toughness remained high at 862 MPa and 10.3 MPa m 1/2 , and could be effortlessly machined with cemented carbide drills. Additionally, the machinability of the composites was systematically characterized through observations of crack propagation paths, fitting of R-curves, and mechanical drilling tests.
研究领域:
材料科学
·
陶瓷工程
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产品关联
DOI
高影响因子
Applied Materials Today
·
2026
·
IF 7
Xian Wu,Xiu Wang,Yiwen Chen,Yifei Qu,Hao Zhang,Tingting Xu,Huiyang Bian,Guigan Fang,Hongqi Dai,Chen Su
Pore structures and interface issues have long impeded significant improvements in the thermal conductivity of biphasic composites. This work introduced a calendering technique, adapted from the traditional papermaking industry, to address these challenges in hexagonal boron nitride/tempo-oxidized cellulose nano-fiber (h-BN/TOCNF) composites. Calendering effectively reduced porosity, enhanced compactness, and improved the interface between the two phases. The results indicated that without calendering, the thermal conductivity of the composites increased with higher h-BN loading. At 50 wt% h-BN content, the through-plane thermal conductivity reached 0.82 W/m·K, which was 116% higher than that of a pure TOCNF film (0.38 W/mK). Contrary to expectations, higher calendering pressure did not yield better performance. The optimal balance was achieved with the composites containing 30 wt% h-BN processed at 2 MPa (h-BN30/TOCNF-2 composites), achieving a high thermal conductivity of 0.71 W/m·K coupled with the highest mechanical strength (40.21 MPa). This synergistic enhancement was attributed to the molecular slippage of TOCNF and preferential orientation of h-BN induced by appropriate calendering pressure, leading to tighter bonding and the formation of a “brick-mortar-brick” structure conductive to phonon transfer and mechanical reinforcement. This work demonstrates that calendering, a simple and scalable post-processing technique, can effectively engineer the microstructure of biphasic composites, leading to simultaneous enhancement in thermal and mechanical properties.
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产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2024
·
IF 8.3
Sijia Sun,Shuai Zhang,Mingzhu Pan
Intelligent fire warning system is a crucial protective equipment reduce fire hazards . A recent increasing concern is the development of sensitive fire warning materials that can be integrated with combustible materials to provide real-time alarms in the fire. However, current research on improving the sensitivity of fire warning sensors based on temperature-resistance response focuses on constructing continuous conductive networks. The effect of the heat transfer process is ignored, which limits the further improvement of alarm sensitivity. Here, we developed a strategy to improve thermal conductivity . Based on the chitosan (CS) conductive network in Ti 3 O 5 -based fire sensing system, aminated 2D h-BN nanosheets with high temperature resistance and ultrahigh in-plane thermal conductivity were further introduced. The h-BN improves the thermal conductivity of the fire warning coating from 1.43 W/m·K to 2.29 W/m·K. Intelligent fire warning sensors with ultra-sensitivity (1.16 s), low response temperature (170 °C), duration time (12 min) and durability (100 cycles) were successfully prepared by improving thermal conductivity to rapidly transfer heat to Ti 3 O 5 , which leads to a rapid decrease in resistance as the core mechanism. This work proposed an ingenious strategy for the construction of high fire safety and thermal conduction fireproof coatings, which revealed enticing prospects in the field of intelligent coatings.
研究领域:
材料科学
·
传感技术
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产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2019
·Vol. 26
·期 12
·1-9
·
IF 1.53
Chen Jiewei,Shang Jingqi,Xue Feng,Wei Qiushi,Xu Ning,Ding Enyong
This article reports on the high-efficiency preparation of few layers h-BN nanosheets (BNNSs) by a high-pressure homogenizer. Then, the BNNSs/chitosan microspheres (BN-CS-M) are finally prepared by mixing BNNSs with chitosan under alkaline conditions. The BNNSs dispersion is investigated by UV-vis spectrophotometer and Transmission Electron Microscopy. In addition, we use Scanning Electron Microscopy and Laser particle size analyzer to characterize the microscopic and macroscopic morphology of BN-CS-M composites. Raman spectroscopy and Specific surface area testing are also used to explore the intrinsic properties of BN-CS-M. Thermal gravimetric analysis shows that composites with high content of BNNSs possess higher thermal stability. The results show that BNNSs is dispersed in the network of chitosan microspheres, and the higher the rate of centrifugation, the fewer BNNSs dispersed in the microspheres. The chitosan microspheres composite with pore diameters in the range of 1.7–2.9 nm belongs to the type IV adsorption curve.
研究领域:
材料科学
·
纳米技术
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Yuehan Cao,Ruiyang Zhang,Tianli Zhou,Shengming Jin,Jindi Huang,Liqun Ye,Zeai Huang,Fang Wang,Ying Zhou
Limited by the chemical inertness of CO2 and the high dissociation energy of the C═O bond, photocatalytic CO2 conversion is highly challenging. Herein, we prepare ultrathin oxygen-modified h-BN (O/BN) nanosheets containing B–O bonds. On the O/BN surface, CO2 can be chemically captured and is bonded with the B–O bond, leading to the formation of an O–B–O bond. This new chemical bond acting as an electron-delivery channel strengthens the interaction between CO2 and the surface. Thus, the reactants can continuously obtain electrons from the surface through this channel. Therefore, the majority of gaseous CO2 directly converts into carbon active species that are detected by in situ DRIFTS over O/BN. Moreover, the activated energies of CO2 conversion are significantly reduced with the introduction of the B–O bond evidenced by DFT calculations. As a result, O/BN nanosheets present an enhanced photocatalytic CO2 conversion performance with the H2 and CO generation rates of 3.3 and 12.5 μmol g–1 h–1, respectively. This work could help in realizing the effects of nonmetal chemical bonds in the CO2 photoreduction reaction for designing efficient photocatalysts.
研究领域:
材料科学
·
环境科学
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DOI
PubMed
高影响因子
Cell Reports Physical Science
·
2022
·
IF 7.832
Tangyou Sun,Jie Tu,Zhiping Zhou,Rong Sun,Xiaowen Zhang,Haiou Li,Zhimou Xu,Ying Peng,Xingpeng Liu,Peihua Wangyang,Zhongchang Wang
Two-dimensional materials resistive random-access memories (RRAMs) are known to exhibit excellent nonvolatile resistive switching (NVRS) performance. However, most two-dimensional materials are produced as monocrystal films with little attention paid to their stacked, discontinuous, and loose polycrystal states, which may allow for more facile atomic diffusion. Here, we propose a liquid-phase self-assembly (LPSA) method to fabricate stacked hexagonal boron nitride (h-BN) polycrystal film (SHPF) and demonstrate its NVRS behavior. Three device architectures with different electrodes are studied, all of which exhibit resistive switching behaviors. The Al/h-BN/Pt device shows 120 current-voltage (I-V) sweeps without degradation, and the Al/h-BN/ITO device exhibits an on/off ratio of ∼10 4 . The proposed LPSA method can serve as a facile and low-cost way to fabricate memory materials on arbitrary substrates. Moreover, stacked, discontinuous, and loose polycrystal film can facilitate the study of NVRS, which opens up an additional avenue for many potential functional applications.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 21
·
IF 3.057
Lijuan He,Junji Zeng,Yuewu Huang,Xiong Yang,Dawei Li,Yu Chen,Xiangyu Yang,Dongbo Wang,Yunxiao Zhang,Zhendong Fu
Low-density polyethylene (LDPE), as an excellent dielectric insulating material, is widely used in electrical equipment insulation, whereas its low thermal conductivity limits its further development and application. Hexagonal boron nitride (h-BN) filler was introduced into LDPE to tailor the properties of LDPE to make it more suitable for high-voltage direct current (HVDC) cable insulation application. We employed melt blending to prepare h-BN/LDPE thermally conductive composite insulation materials with different contents. We focused on investigating the micromorphology and structure, thermal properties, and electrical properties of h-BN/LDPE composites, and explained the space charge characteristics. The scanning electron microscope (SEM) results indicate that the h-BN filler has good dispersibility in the LDPE at a low loading (less than 3 phr (3 g of micron h-BN particles filled in 100g of LDPE)), as well as no heterogeneous phase formation. The results of thermal conductivity analysis show that the introduction of h-BN filler can significantly improve the thermal conductivity of composites. The thermal conductivity of the composite samples with 10 phr h-BN particles is as high as 0.51 W/(m·K), which is 57% higher than that of pure LDPE. The electrical performance illustrates that h-BN filler doping can significantly inhibit space charge injection and reduce space charge accumulation in LDPE. The interface effect between h-BN and the substrate reduces the carrier mobility, thereby suppressing the injection of charges of the same polarity and increasing the direct-current (DC) breakdown strength. h-BN/LDPE composite doped with 3 phr h-BN particles has excellent space charge suppression effect and high DC breakdown strength, which is 14.3% higher than that of pure LDPE.
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DOI
高影响因子
危险品化学品经营许可证（带存储）