CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jiangang Chen,Meixia Cai,Ying Liu,Panpan Yang,Jiping Wang
This paper develops a novel adhesive for in-situ joining C/C composites to C/C-SiC composites using a phenolic resin modified with inert fillers (SiC and graphite powders). The primary phase of the reaction bonding joint layer is SiC, which matches the thermal expansion coefficient of the matrix better than metallic phases, making it an improvement over traditional brazing. The effect of filler content on joint strength, oxidation resistance, and thermal shock resistance has been systematically investigated. The results show that increasing the filler content from 0 to 50 wt% increases shear strength up to a maximum of 25.97 MPa at 15 wt% SiC and 15 wt% graphite powder. The oxidation and thermal shock tests reveal that the joints exhibit a decrease in shear strength due to oxidation at temperatures above 600 °C, with a significant reduction occurring between 600 °C and 700 °C. After seven thermal shock cycles at 800 °C, the shear strength of the joints remains relatively high, indicating the good thermal shock resistance of the bonding layer. The method proposed in this study provides a new approach for controlling residual silicon and enhancing the properties of C/C-SiC joints.
研究领域:
材料科学
·
复合材料
·
连接技术
·
热分析
·
陶瓷基复合材料
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2022
·
IF 13.7
Xuliang Lin,Xing Fei,Dalang Chen,Yi Qi,Quanzhou Xu,Yinchun Liu,Qian Zhang,Sha Li,Tiejun Wang,Yanlin Qin,Xueqing Qiu
The conversion of renewable bioethanol into high-energy-density higher alcohols has become essential for meeting the increasing global demand to achieve carbon neutrality. In this study, Zn- and nitrogen-codoped Ni-based lignin-derived carbon catalysts (NiZn@NC) were prepared by solvent volatile self-assembly and in situ reductive carbonization using pulp and paper waste stream alkali lignin as the carbon source. Lignin amphipathic derivatives with −COOH and −NH2 groups would coordinate with metal ions to form a stable lignin–metal framework; thus, the lignin-derived carbon layer disperses the NiZn bimetallic catalyst and prevents from corroding. At an amination reagent/lignin mass ratio of 1:2, an ethanol conversion of 75.2% and a high alcohol yield of 41.7% were achieved over the Ni20Zn1@NC catalyst. Experimental results and density functional theory calculations showed that Zn doping improved the electronic environment and defect structures of metallic Ni and carbon carrier, which effectively inhibited C–C cleavage and suppressed the byproduct formation, such as methane. Thereby, the synergetic effect between Ni and Zn facilitated the efficient conversion of aqueous ethanol into higher alcohols by the Guerbet reaction. This work provides a strategy of in situ pyrolytic doping and stabilizing of renewable biomass macromolecules as the frameworks for the construction of highly active and cost-efficient catalysts for ethanol upgrading.
研究领域:
催化化学
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可再生资源利用
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材料科学
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Xiaohui Leng,Xin Zhou,Lu Ma,Yonghua Du,Ouwen Peng,Zhongxin Chen,Jinhui Pan,Ming-Yu Qi,Jian-Hui Zheng,Yi-Jun Xu,Kian Ping Loh
Visible light induced oxidative C–C and C–N coupling provides a milder alternative to the current synthetic strategies. However, the photochemical C–C coupling of benzylamine and chromoselective C–C/C–N conversion are not widely reported. Herein, we demonstrate that the introduction of indium vacancies in ZnIn2S4 improves the catalytic activity for C–C coupling of benzylamine and imparts a strong chromoselectivity for C–C or C–N coupled products. A high C–C selectivity of ∼80% is achieved with a benzylamine conversion of ∼80%. Mechanistic studies unveil the switchable reaction routes between kinetically favored C–C coupling and thermodynamically favored C–N coupling under specific illumination conditions.
研究领域:
化学
·
材料科学
·
光催化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Zhizhou Cai,Ning Cao,Fanxing Zhang,Xiangzhou Lv,Ke Wang,Yi He,Yao Shi,Hao Bin Wu,Pengfei Xie
Electrocatalytic CO 2 reduction into ethanol driven by renewable energy represents a promising strategy for energy storage and mitigation of global warming, but it has remained challenging to gain high activity and selectivity of ethanol. Here we take advantage of atomic arrangement in immiscible Ag-Cu composite during annealing and establish hierarchical interfaces in the obtained core-shell catalyst. The atomic Ag-Cu interactions increase electrochemical surface area and expedite charge dynamics, resulting in an unprecedented electrocatalytic performance with the faradaic efficiency of C 2+ products, ethanol as 80.2 %, 52.6 % and the current density of ∼320 mA cm −2 at −1.0 V (versus reversible hydrogen electrode). Moreover, the Ag-Cu catalyst exhibits a notable stability for ∼60 h. Mechanism studies reveal that local CO intermediates preferentially accumulate on the core, then migrate to the continuous Cu surface for C-C coupling energy-favorably toward ethanol. Our work highlights a novel design principle as interface engineering for advanced tandem electrocatalysts.
研究领域:
材料科学
·
电化学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2019
·
IF 12.221
Huifang Liu,Hongji Li,Nengchao Luo,Feng Wang
Lignin is the largest carrier of aromatics on earth, and its depolymerization can afford value-added aromatic products. Direct cleavage of the C–C bonds in lignin linkages is significant, but it is challenging to obtain low-molecular-weight aromatic monomers. Herein, using vanadium catalysts under visible light, we selectively cleave the C–C bonds in β-1 and β-O-4 interlinkages occluded in lignin models and extracts by an oxidative protocol. Visible light irradiation triggered single electron transfer between the substrate and the catalyst, which further induced the selective Cα–Cβ bond cleavage and generated the final aromatic products through radical intermediates. Using this photocatalytic chemistry, the reactivity of lignin models and the selectivity of Cα–Cβ bond cleavage were significantly improved. More importantly, this protocol affords aromatic monomers through the fragmentation of organosolv lignins even at room temperature, indicating the potential of photocatalytic C–C bond cleavage of lignin linkages under ambient conditions.
研究领域:
化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-11
·
IF 14.7
Yang Ruixin,Cai Yanming,Qi Yongbing,Tang Zhuodong,Zhu Jun-Jie,Li Jinxiang,Zhu Wenlei,Chen Zixuan
C–C coupling is of utmost importance in the electrocatalytic reduction of CO 2 , as it governs the selectivity of diverse product formation. Nevertheless, the difficulties to directly observe C–C coupling pathways at a specific nanocavity hinder the advances in catalysts and electrolyzer design for efficient high-value hydrocarbon production. Here we develop a nano-confined Raman technology to elucidate the influence of the local electric field on the evolution of C–C coupling intermediates. Through precise adjustments to the Debye length in nanocavities of a copper catalyst, the overlapping of electrical double layers drives a transition in the C–C coupling pathway at a specific nanocavity from *CHO–*CO coupling to the direct dimerization of *CO species. Experimental evidence and simulations validate that a reduced potential drop across the compact layer promotes a higher yield of CO and promotes the direct dimerization of *CO species. Our findings provide insights for the development of highly selective catalyst materials tailored to promote specific products.
研究领域:
催化化学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Wen Zhang,Yingxiu Zhao,Jiayi Li,Yu Miao,Pengkai He,Zexing Wu,Yang Zhang,Guang-Rui Xu,Lei Wang
The capacity of C‒C bond cleavage determines the pathway selectivity during the ethanol oxidation process. Herein, ultra-thin monodisperse PdCo nanosheets with an average diameter of 33 nm are successfully synthesized and the interface of Pd-O-Co is further constructed due to the introduction of lattice oxygen. Due to their ultra-thin nanosheet structure, unique surface electronic structures driven by lattice oxygen, and alloying effect, the prepared PdCo/Pd-O-Co nanosheets (PdCo/Pd-O-Co NSs) show excellent ethanol oxidation reaction (EOR) activity and stability. The mass activity and specific activity of PdCo/Pd-O-Co NSs are 12.43 A mg −1 and 22.01 mA cm −2 for EOR, which exceeded PdCo nanosheets, Pd nanosheets and commercial Pd black. In situ FTIR spectroscopy and theoretical calculation identified that lattice oxygen introduced after square-wave potential treatment can promote the cleavage of the C‒C bond. Through the introduction of lattice oxygen combined with lattice strain engineering, the PdCo/Pd-O-Co NSs surface is optimized to promote the generation of strong p-d orbital hybridization, which led to the upward shift of the d-band center and the electron delocalization effect, effectively promoting the C‒C bond cleavage and improving the anti-poisoning ability.
研究领域:
材料科学
·
催化化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Zhenxiao Tang,Maozhong Yi,Zhe Zhou,Huang Wu,Yuanming Zhou,Ke Peng
A C/C-TaB 2 -SiC composite was successfully prepared by high-solid-loading slurry impregnation combined with polymer infiltration and pyrolysis. The composite had a density of 3.46 g/cm 3 and consisted of pyrolyzed carbon, carbon fibers, TaB 2 particles, and precursor-derived SiC with their mass fractions of 7.8 %, 13.0 %, 58.6 %, and 20.6 %, respectively. The C/C-TaB 2 -SiC composite possessed a flexural strength of 248.2 ± 16.8 MPa and a fracture toughness of 13.7 ± 1.6 MPa·m 1/2 , and demonstrated a non-brittle fracture behavior . After exposure to oxyacetylene flame with a heat flux of 4.18 MW/m 2 for 120 s, the ablation temperature of the sample surface reached a maximum of 2263 °C, and the mass and line ablation rates were 2.24 mg/s and 12.92 µm/s, respectively. The ablation resistance mainly comes from the hindrance of oxygen diffusion by the oxide layer composed of tantalum oxide and a small amount of SiO 2 .
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2012
·
IF 4.805
Yuewu Zhao,Huile Jin,Huan Zhou,Juanjuan Lin,Shun Wang,Jichang Wang
Te@Pd core–shell hybrids were prepared in this study, in which a pine leaf-shaped microstructure was obtained through controlling the synthesis kinetics of single crystal Te. The as-prepared Te was subsequently utilized as the substrate for Pd coating. These core–shell particles were characterized with scanning and transmission electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. When being applied as a catalyst in bromobenzene and phenylboronic acid reaction, 100% conversion of bromobenzene was achieved in less than 3 h, which was much shorter than that required by the reactions using graphene oxide supported Pd catalyst (4 h) or the commercial Pd/C catalyst (>6 h). The Te@Pd core–shell catalyst could be easily recovered from the reaction solution and be used repeatedly. The high catalytic activity of Te@Pd hybrids is attributed to their unique microstructure.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
·
2023
·Vol. 120
·期 44
·e2307320120
·
IF 11.1
Yangyang Yu,Ye He,Ping Yan,Shengyao Wang,Fan Dong
The selective photocatalytic conversion of CO2 and H2O to high value-added C2H4 remains a great challenge, mainly attributed to the difficulties in C–C coupling of reaction intermediates and desorption of C2H4* intermediates from the catalyst surface. These two key issues can be simultaneously overcome by alloying Ag with Cu which gives enhanced activity to both reactions. Herein, we developed a facile stepwise photodeposition strategy to load Cu–Ag alloy sub-nanoclusters (ASNCs) on TiO2 for CO2 photoreduction to produce C2H4. The optimized catalyst exhibits a record-high C2H4 formation rate (1110.6 ± 82.5 μmol g−1 h−1) with selectivity of 49.1 ± 1.9%, which is an order-of-magnitude enhancement relative to current work for C2H4 photosynthesis. The in situ FT-IR spectra combined with DFT calculations reveal the synergistic effect of Cu and Ag in Cu–Ag ASNCs, which enable an excellent C–C coupling capability like Ag and promoted C2H4* desorption property like Cu, thus advancing the selective and efficient production of C2H4. The present work provides a deeper understanding on cluster chemistry and C–C coupling mechanism for CO2 reduction on ASNCs and develops a feasible strategy for photoreduction CO2 to C2 fuels or industrial feedstocks.
研究领域:
化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Xuhui Wang,Jianying Wang,Zihe Chen,Kai Yang,Zexian Zhang,Zhuoxun Shi,Tao Mei,Jingwen Qian,Jinhua Li,Xianbao Wang
Herein, yolk-double shell Fe 3 O 4 @C@C nanospheres (YDS-FCCNs) were designed and synthesized via solvothermal and following heat management. The as-obtained yolk-shell morphology consisted by two parts: one for the Fe 3 O 4 @C nanosphere (diameter about 100 nm) as core, and the other for nitrogen-doped carbon (thickness about 50 nm) as the shell. The YDS-FCCNs composite exhibited preeminent cycling stability of 780 mAh/g at 0.5 A/g after 500 cycles, even at higher current density of 2 A/g, it still retained a reversible capacity of 559 mAh/g after 500 cycle. The good electrochemical performance could attribute to the following factors: First, the hierarchical double carbon shell could prevent the agglomeration of the Fe 3 O 4 , meanwhile largely enhance the electrical conductivity . Second, the synergistic effects for multilayered structure and atomic doping could improve the comprehensive electrochemical performance.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
ChemSusChem
·
2020
·Vol. 13
·期 19
·5248-5255
·
IF 7.962
Rui Zhu,Gongyu Zhou,Jia-nan Teng,Xinglong Li,Yao Fu
Graphical Oxidative cleavage : A heterogeneous metal-free photocatalytic system is developed for oxidative cleavage of C−C bonds in 1,2-diols at mild conditions (visible light, room temperature, no base, O 2 balloon). The reaction mechanism is studied through a series of control experiments and DFT calculations. In addition, the catalytic system has a broad substrate scope, including aliphatic, benzylic, alkenyl 1,2-diols, and α-hydroxy acids such as lactic acid. The preparation of carbonyl compounds by the aerobic oxidative cleavage of C−C bonds in 1,2-diols under mild reaction conditions is a very significant reaction and is widely employed in various scenarios. Avoiding the use of harmful stoichiometric oxidants and adopting a greener chemical process remain a challenge for this reaction to date. In this manuscript, a heterogeneous metal-free photocatalytic strategy without any additive was developed for aerobic oxidative cleavage of C−C bonds in 1,2-diols at ambient conditions with visible light. The reaction mechanism was further studied through a series of control experiments and density functional theory (DFT) calculations. In addition, the catalytic system showed a broad substrates scope, including aliphatic (linear or cyclic) 1,2-diols, benzylic, alkenyl 1,2-diols, and α-hydroxy acids (such as lactic acid). Thus, this strategy could serve as a method for the transformation of 1,2-diols to corresponding carbonyl compounds by the aerobic oxidative cleavage of C−C bonds.
研究领域:
有机化学
·
催化化学
·
环境化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）