International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Mingde Tong,Xinhao Shi,Tao Feng,Ying Dai,Pengfei He
To achieve the repeatability of aerospace thermal components, C/TaC‒SiC composites were fabricated. Cycle ablation and bending tests were carried out. After 3 × 60 s of ablation beyond 2100°C, the mechanical property retention rate was 80.9%. Interestingly, a reaction similar to “ouroboros ring,” in which the cyclic reactions of “TaC being oxidized to Ta 2 O 5 and Ta 2 O 5 being reduced to TaC,” occurred in the central ablation region of C/TaC‒SiC composites. On the one hand, the continuous generation of TaC could prevent liquid state Ta 2 O 5 from being blown off central ablation region, playing a similar role in “water and soil conservation.” On the other hand, liquid Ta 2 O 5 covered the surface of C/TaC‒SiC composites during ablation process, contributing to block the inward permeation of oxidized gases. In addition, novel “Grotto” structures were detected in the transitional ablation region of C/TaC‒SiC composites. The formation reason of the “Grotto” structure has also been discussed.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Cuiyan Li,Guibiao Li,Haibo Ouyang,Jianfeng Huang,Xianghui Hou
Carbon fiber reinforced carbon matrix containing ZrC (C/C–ZrC) composites were prepared by hydrothermal deposition combined with carbothermal reduction. The submicron ZrC particles (100–300 nm) were dispersed in the matrix. The stress-strain curves of the composites presented a typical pseudo-plastic fracture behavior . The mass and linear ablation rates of the composites were 3.7 × 10 −3 g/s and 4.2 × 10 −3 mm/s, respectively. The formation of ZrO 2 glass layer reduced erosion of the composites in the ablation center. The continuous C–ZrC–ZrO 2 skeleton layer generated from the oxidation of ZrC can protect the composites from erosion at the ablation brim region. The obtained C/C–ZrC composites present a promising potential as ablation resistance materials.
研究领域:
材料科学
·
复合材料工程
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Zhixiu Yang,Xiaoxuan Guo,Yong Chen,Lijing Gao,Ruiping Wei,Guomin Xiao
Modulating the surface microenvironment is crucial in strengthening C C coupling, leading to increasing selectivity in the production of multi-carbon (C 2+ ) products during CO 2 electroreduction. Herein, we have concentrated on investigating how to control the effect of surface distribution of active components of a series of Ag-decorated CuO , denoted as xAg/yCuO. These catalysts with similar chemical elements and morphology are designed, but they exhibit different selectivity in the CO 2 electroreduction process. As a result, the Ag particles in 3Ag/CuO aggregates, while the Ag in 2Ag/2CuO and Ag/3CuO is uniformly distributed on the flower-like CuO nanosphere . Besides, 3Ag/CuO has the highest Faraday efficiency (FE) of CO with a value of 30.9 % at 0.8 V vs. RHE, demonstrating rich-Ag catalysts are beneficial to produce CO. 2Ag/2CuO shows excellent FE C2H4 of 51.4 % at -1.2 V vs. RHE due to the highly dispersed distribution of Ag on the flower-like CuO and higher vacancy O. Ag/3CuO exhibits higher FE H2 compared to other catalysts across a wide potential range, and its minimal impedance is attributed to its exceptional performance in the hydrogen evolution reaction . The proposed reaction pathway for the most effective catalysts 2Ag/2CuO, as determined by in-situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), involves the following steps: CO 2 →*CO 2 − → *COOH → *CO→ *CHO→ *OCHCHO→ *OCHCH 2 → C 2 H 4 . These findings demonstrate that controlling the surface structure can influence the local environment to enhance the efficiency of CO 2 electroreduction.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Energy Storage Materials
·
2023
·
IF 20.4
Chengyao Zhao,Yiming Lin,Qiaoyan Lin,Qi Liu,Yujing Liu,Zhongqiu Liu,Anguo Ying
Aqueous zinc-ion hybrid capacitors (ZIHCs) are a promising new type of energy storage device, but there is a plight that the unsatisfactory Zn 2+ storage capability of carbonaceous cathodes limits further application. To address this issue, desolvation strategy is employed to tailor the solvation sheath of Zn 2+ in the ultra-micropores (0.59 nm) nanospheres , where H 3 PO 4 acts as phosphorus source for forming C-P bonds and enhancing C=O bonds to further reduce the desolvation energy barrier. In practical application, a quasi-solid-state flexible ZIHC is constructed, which provides a battery-level energy density (293.4 Wh kg −1 ) at a power density (180 W kg − 1 ) and a remarkable capacity retention of 93.4 % after 10 000 cycles. Electrochemical analyses, DFT calculations and structural characterization reveal that ultra-microporous is proved to be a prerequisite for C-P/C=O that are expected to further deplete solvent molecules within a Zn 2+ solvation sheath. Also, the coupling effect between the strong adsorption of Zn 2+ by C-P/C=O and the hydrophobic effect of C-P play an important role in facilitating desolvation process. This work creates a precedent for the application of ultra-microporous carbon materials in ZHICs and provides a brand-new approach for breaking the bottleneck of the low energy density and poor lifespan of ZHICs.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2025
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IF 6.6
Yuanming Zhou,Zhenxiao Tang,Ruizhi Liu,Zhe Zhou,Maozhong Yi,Ke Peng
To further enhance the ablation resistance of C/C composites, solid solution ceramic Ta 0.2 Zr 0.8 C was used to replace traditional ultra-high-temperature ceramic carbides for matrix modification of C/C composites. The C/C-Ta 0.2 Zr 0.8 C-SiC composite was fabricated by a high-solid-loading slurry impregnation combined with the precursor infiltration and pyrolysis process. The comparative samples of C/C-ZrC-SiC and C/C-TaC-SiC were also prepared using these same technologies. The microstructure, flexural properties, and ablation performance of the composite were investigated. Results showed that the C/C-Ta 0.2 Zr 0.8 C-SiC exhibited excellent overall flexural properties. During the ablation test under an oxyacetylene flame with high heat flux, the ablation resistance of C/C-Ta 0.2 Zr 0.8 C-SiC improved with prolonged ablation time, reaching mass and linear ablation rates of 0.67 mg/s and 0.18 μm/s after 120 s of ablation. Compared to the C/C-ZrC-SiC and C/C-TaC-SiC, the mass ablation rate of the composite was reduced by 49.24% and 68.70%, and the linear ablation rate was reduced by 97.22% and 97.71%, respectively. The enhanced ablation resistance was primarily attributed to the formation of the Ta-Zr-O oxide layer, composed of TaZr 2.75 O 8 , ZrO 2 , and Ta 2 O 5 , on the composites surface. In the oxide layer, the Ta-rich oxides served as a binder, filling gaps in the interface. Meanwhile, the Zr-rich oxides formed the skeleton that pinned the molten liquid oxides. The combined effects of Ta-rich and Zr-rich oxides made the Ta-Zr-O oxide layer more compact and strongly bonded to the matrix.
研究领域:
材料科学
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航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Fuhai Liu,Maozhong Yi,Liping Ran,Yicheng Ge,Zhe Zhou,Ke Peng
C/C-BN-SiC composite was prepared by ceramic slurry infiltration combined with resin impregnation and carbonization, and the matrix with continuous distributed self-healing phase was obtained. In this study, the kinetic characteristics and oxidation behavior of the composites with various h-BN/SiC ratios in the temperature range of 600∼1300°C were studied by combining the isothermal oxidation test with the kinetic model. The optimal h-BN/SiC ratio balances the thermal stability and fluidity of the oxidized product, which not only has high thermal stability and low oxygen permeability to acts as an oxygen diffusion barrier but also has a certain fluidity to seal defects.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·Vol. 34
·期 44
·2405922
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IF 18.5
Minmin Ma,Ran Wang,Li Shi,Ronghua Li,Jie Huang,Zhuo Li,Peng Li,Elena Yu. Konysheva,Yanbo Li,Gang Liu,Xiaoxiang Xu
Photocatalytic carbon-carbon (C─C) coupling of benzyl alcohol is a promising means to coproduce the value-added chemicals with H 2 but is generally subject to low efficiency in terms of photon utilization. Here, efficient benzyl alcohol C─C coupling is achieved over Zn 2 In 2 S 5 containing a tunable content of Zn vacancies ( V Zn ). The V Zn tends to form shallow defect states below the conduction band that can expedite photocarrier separation by collecting the photo-generated electrons. The V Zn -collected electrons are essential for a high selectivity of the C─C coupling reactions because they enable a fast elimination of the byproduct benzaldehyde by catalyzing its reduction back to the ketyl radicals. Under simulated sunlight, the V Zn -containing Zn 2 In 2 S 5 accomplishes ≈100% conversion of benzyl alcohol for merely 1 h and attains ≈100% selectivity for the C─C coupling compounds for 2 h, delivering an apparent quantum yield as high as 7.7% at 420 ± 20 nm. The benefits of V Zn have also been verified by the theoretical calculations that indicate reduced energy barriers for various surface reactions in the presence of V Zn . This work brings fresh mechanistic insights into the role of V Zn and can serve as a useful guideline in the design of efficient photocatalysts.
研究领域:
材料科学
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光催化化学
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
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IF 21.1
Wei Wei,Zhenyao Li,Jitao Shang,Chenxi Xia,Xuli Hu,Yangshun Hu,Junchen Xu,Yan Zhao,Mingyue Ding
The selective electrochemical reduction of CO to valuable multi-carbon (C 2 + ) products is a key strategy for mitigating global warming and addressing the energy crisis. Nevertheless, the activity and selectivity of CO-to-C 2+ products conversion remain low due to the lack of effective catalysts. In this study, bimetallic CuPd was grown in situ on Cu nanoparticles via a seed-mediated approach, constructing a stable CuPd/Cu interface for the CO reduction reaction (CORR). The CuPd alloy promotes CO adsorption and hydrogenation, resulting in abundant and stable *COH intermediates over catalytic sites. Consequently, a stable asymmetric coupling is established at the CuPd/Cu interface, lowering the reaction energy barrier and facilitating C-C coupling. A high acetate selectivity of 49 % was achieved at –1.0 V versus the reversible hydrogen electrode (RHE) with a current density of 349 mA/cm². This study highlights the critical role of constructing CuPd/Cu asymmetric sites for C–C coupling, paving the way for designing highly selective catalysts that enhance C 2+ product formation and acetate production.
研究领域:
材料科学
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电化学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2013
·Vol. 27
·期 6
·337-340
·
IF 2.011
Junyu Dong,Tianbin Li,Chuan Dai,Wen Weng,Xinghua Xue,Yuyu Zhang,Qingle Zeng
A straightforward, protecting-group-free protocol for the synthesis of chiral 6-substituted and 6,6’-disubstituted binols (binol = 1,1’-bi-2-naphthol) by palladium-catalyzed hydroxylation, C–N and C–O coupling of chiral 6-bromo- and 6,6’ -dibromo-1,1’-binaphthols is developed. The protecting group free palladium-catalyzed hydroxylation, C–O and C–N cross-coupling protocol affords a straightforward and general method for the synthesis of chiral 6-substituted and 6,6’-disubstituted binols with good yields, avoiding the tedious procedures of introduction and removal of protecting groups. Copyright © 2013 John Wiley & Sons, Ltd.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Yunjia Wei,Qi Hao,Xingce Fan,Mingze Li,Lei Yao,Guoqun Li,Xing Zhao,Hao Huang,Teng Qiu
The implementation of plasmonic materials in heterogeneous catalysis was limited due to the lack of experimental access in managing the plasmonic hot carriers. Herein, we propose a liquid-state surface-enhanced Raman scattering (SERS) technique to manipulate and visualize heterogeneous photocatalysis with transparent plasmonic chips. The liquid-state measurement conquers the difficulties that arise from the plasmon-induced thermal effects, and thus the plasmon based strategies can be extended to investigate a wider range of catalytic reactions. We demonstrated the selection of reaction products by modulating the plasmonic hot carriers and explored the mechanisms in several typical C–C coupling reactions with 4-bromothiophenol (4-BTP) as reactants. The real-time experimental results suggest brand new mechanisms of the formation of C–C bonds on plasmonic metal nanoparticles (NPs): the residue of 4-BTP, but not thiophenol (TP), is responsible for the C–C coupling. Furthermore, this technique was extended to study the evolution of the Suzuki–Miyaura reaction on nonplasmonic palladium metals by establishing the charge transfer channels between palladium and Au NPs. The cleavage and formation of chemical bonds in each individual reaction step were discerned, and the corresponding working mechanisms were clarified.
研究领域:
催化化学
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材料科学
·
光化学
✓ 已验证
DOI
高影响因子
MONATSHEFTE FUR CHEMIE
·
2014
·Vol. 145
·期 12
·1925-1931
·
IF 1.347
Tu Xingzhao,Zhou Lihong,Li Zhijie,Lei Ning,Zeng Qingle
Abstract The carbon-heteroatom bond formation is an important research field. Transition-metal-free synthesis of medicinally important heterocycles avoids products of transition metal contamination, and thus it is an environmentally friendly and cost-saving process. A transition-metal-free domino C-S/C-N formation for the synthesis of imidazobenzothiazines from 2-mercaptobenzimidazoles and 2-halobenzyl bromides is developed. The desired products were obtained in good to excellent yields. The mechanism of domino nucleophilic substitution (S N 2) and nucleophilic aromatic substitution (S N Ar) is proposed. Graphical abstract
研究领域:
有机化学
·
药物化学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED COMPOSITE MATERIALS
·
2022
·Vol. 29
·期 6
·2147-2163
·
IF 2.368
Wang Pei,Guo Yonggang,Du Sanming,Jia Yunchao,Zhang Hongbo,Yin Jian
Taking the advantages of porous ceramic (C/C-SiC composite) and transpiration cooling (Copper alloy), C/C-SiC-Cu composite was fabricated to attain a novel anti-ablation material for high temperature structure application of aerospace systems, via chemical vapor deposition and infiltration technologies. The effects of SiC content on microstructure, thermal conductivity, mechanical and ablation properties of C/C-SiC-Cu composite were investigated. As the SiC content increases from 0 vol% to 25.12 vol%, thermal conductivity, flexural strength and ablation resistance are improved by 84.99%, 78.76% and 53.68%, respectively. Thermal conductivity and thermal diffusivity exhibit proportional linear correlation with SiC content. The high SiC content could shorten the yield stage and increase the breaking strength during the flexural fracture process. When the SiC content is 25.12 vol%, the formation continuous and compact anti-ablation (SiO 2 ) layer is formed by oxidizing and melting fluidity processes during oxyacetylene ablation test, and the protective layer covers the ablation surface and slows down the oxidative ablation, which combines with the transpiration cooling effect of copper alloy to further improve ablation resistance of C/C-SiC-Cu composite.
研究领域:
航空航天材料科学
·
高温结构材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）