APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2024
·Vol. 130
·期 4
·1-14
·
IF 2.5
Guo Chenxi,Yang Xin,Zhang Xiaxiang,Li Hongtao,Liao Mingdong,Huang Qizhong
To shorten the manufacturing process and enhance the ZrC content, C/C-SiC-ZrC composites were prepared using the nano-filler slurry infiltration method in combination with precursor infiltration and pyrolysis method. The effect of ZrC filler sizes on densification, microstructure, and properties of composites was studied. Results revealed that the ZrC content and density of the C/C-SiC-ZrC composites are inversely correlated to the filler size. The composites with nano-fillers reach the highest density of 2.67 g cm −3 as well as the lowest open porosity of 1.21%. After being ablated under oxyacetylene flame for 60 s, the composites with nano-fillers owns the lowest linear ablation rate and surface temperature, with 10 μms −1 and 2700 °C. Due to the highest ZrC content and best film-forming ability of nano-fillers, ZrO 2 outer layer with the densest structure can provide an enhanced protective effect, and the thickness of the oxide layer decreases from 509 to 264 μm as compared with micron fillers. Therefore, the oxidation damage of the composites is reduced, and the thickness of the SiC depletion layer decreases simultaneously. The above results further demonstrate that introducing ZrC nano-filler to the C/C-SiC-ZrC composites can considerably improve their ablative properties at 2700 °C.
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Cuiyan Li,Siyi Qi,Haibo Ouyang,Tianzhan Shen,Zihao Chen,Yanlei Li,Jiaqi Liu
To develop active thermal protection for ultra-high temperature ceramics, C/C-ZrC-CuNi composites were fabricated using a PIP method. This study systematically studied the influence of CuNi alloy content on the microstructure, mechanical properties, thermal conductivity, and ablation resistance of the composites. The incorporation of CuNi alloy significantly enhanced the sintering of the ZrC-C matrix, resulting in improved densification of the composites. Furthermore, the presence of CuNi alloy promoted the graphitization of the carbon matrix, thereby enhancing the thermal conductivity. The composites with the highest CuNi alloy content (ZCN4 sample) exhibited the greatest density（2.26 g/cm 3 ） and thermal conductivity（32.3 W/m·k）, along with superior ablation resistance, with mass and line ablation rates of 2.09 mg/s and 2.06 μm/s. This enhanced ablation resistance can be primarily attributed to the sweating cooling effect of the CuNi alloy, which effectively reduces the ablation temperature. Additionally, the formation of Cu 2 O and NiO during ablation acts as sintering aids, facilitating the development of a compact ZrO 2 scale that resists flame erosion. The increased thermal conductivity of the composite further mitigates the temperature rise on the ablation surface.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Chen Xie,Shaolei Song,Guanzhong He,Zhihui Mao,Cuncheng Ma,Tong Zhang,Pengfei Hu,Qiang Zhen
Poor antioxidant and thermal-shock capacities of C/C composites thermal barrier coating (TBC) caused by cracking and shedding of coatings has been a major obstacle blocking the development of C/C composites. Herein, in-situ growth of whisker reinforced silicon carbide transition layer and inter-embedding mechanism of multi-gradient coatings were brought into the design of TBC to enhance the antioxidant and thermal-shock capacities. A three-layer gradient coating SiC-SiC w /ZrB 2 -SiC/ZrSiO 4 -aluminosilicate glass (ZAG) from inside to outside, in which ZrB 2 -SiC/ZAG serve as oxygen barrier layers with self-healing ability and SiC-SiC w provides thermal stress buffering and bonding against cracking and shedding of coatings, is designed. The ZAG mainly forms a dense oxygen blocking frontier with self-healing ability through fluidized glass, while the ZrB 2 -SiC can react actively with infiltrated oxygen in a way of self-sacrifice, preventing oxygen erosion to C/C matrix and SiC-SiC w transition layer. As a result, the collaborative work among layers endows this coating with excellent high temperature service performance. This work provides a new insight for the design of excellent TBC.
✓ 已验证
DOI
高影响因子
Materials Today Energy
·
2026
·
IF 8.1
Yipeng Nie,Longquan Deng,Zipei Cui,Zhao Jiang,Wenchao Sheng
Coupling hydrogen evolution reaction (HER) with glycerol oxidation reaction (GOR) in a hybrid electrolyzer represents a highly promising approach for green hydrogen production and glycerol upgrading. However, the limited activity and stability of existing GOR catalysts restrict the energy efficiency of the coupled system. In this study, Pd/C and Pd 4 Ag x /C catalysts were synthesized to investigate the impact of Ag on the activity and stability of Pd-based catalysts for GOR. The optimized Pd 4 Ag 8 /C demonstrated a specific activity of 17.4 ± 0.1 mA cm −2 Pd and a mass activity of 13.2 ± 0.3 A mg −1 Pd , both being more than 10 times higher than those of Pd/C. Combined results of ultra-performance liquid chromatography and density functional theory calculations revealed that the introduction of Ag promotes C−C cleavage in glyceric acid on Pd sites, facilitating electron transfer in GOR and thereby enhancing the GOR activity. The GOR coupled HER hybrid electrolyzer using Pd 4 Ag 8 /C as the GOR catalyst achieved a significant reduction of ∼1.07 V in cell voltage compared to conventional water electrolysis system at a current density of 10 mA cm −2 with a favorable operational stability, and realized the production of high-value-added chemicals, demonstrating the promising potential in both hydrogen production and upgrade of glycerol.
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2026
·
IF 13.6
Du Ruiqi,Guo Na,Zhang Yinan,Chen Zemao,He Junliang,Zhang Chun,Cheng Yi
The oxidative cleavage of C–C bonds is a key reaction pathway in the electrocatalytic valorization of biomass-derived alcohols. However, the influence of molecular branching on this process remains poorly understood. Herein, we establish a nucleophilic hydroxide-mediated C–C cleavage mechanism on Ni(OH) 2 catalyst using isobutanol as a model β-branched primary alcohol. Combining 18 O isotope labeling with in situ mass spectrometry, we demonstrate that isobutyraldehyde is the key intermediate and that hydroxide anions (OH – ), rather than surface-adsorbed *OH, act as the active species driving C–C cleavage. Density functional theory (DFT) studies reveal that the β-branching creates steric hindrance that suppresses C–H dehydrogenation while simultaneously strengthening the van der Waals adsorption of the isobutyraldehyde intermediate. This enhanced adsorption lowers the energy barrier for nucleophilic attack by OH – . This work establishes a fundamental structure–reactivity relationship, offering a strategic blueprint for modulating reaction pathways in biomass upgrading.
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2026
·
IF 4
Yuzhen Hu,Ruiying Xiong,Xin Qu,Taras Nagornyy,Zhenlong Song,Xingye Zeng,Ning Li,Qi Zhang,Longlong Ma
Selective C-C bond cleavage in lignin is a pivotal step toward its efficient utilization, enabling the production of diverse and valuable chemicals from this abundant and renewable resource. Among the catalysts reported for oxidative cleavage of C-C bond in lignin β-O-4 ketones, CeO₂-supported Pd catalysts have demonstrated outstanding activity. However, the exact nature of the active Pd sites responsible for C-C bond cleavage remains poorly understood, limiting mechanistic insights into this transformation. In this study, CeO₂ supports with four distinct morphologies including rods (R), spheres (S), cubes (C), and polyhedrons (P) were synthesized to investigate their influence on the catalytic activity of Pd/CeO₂ catalysts in the oxidative cleavage of β-O-4 ketones. The catalytic performance was found to depend strongly on the morphology of CeO₂, with Pd/CeO₂-P exhibiting the highest activity for C-C bond cleavage. This catalyst possessed the lowest Pd⁴⁺ content and the highest Pd⁰/Pd²⁺ ratio among the series. By systematically tuning this ratio, a volcano-type relationship between Pd⁰/Pd²⁺ ratio and catalytic activity was established, indicating a dual-site mechanism in which Pd⁰ facilitates the formation of reactive oxygen species, while Pd²⁺ serves as the active center for C-C bond cleavage.
✓ 已验证
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2026
·
IF 7.3
Yuanxia Lv,Zhihao Zhao,Shijiao Chen,Ru Ma,Ziqin Lu,Zhimin Zhang,Qian Wu,Hongmei Lu
Spatially resolved profiling of lipid carbon–carbon double bond (C═C) isomers, especially for poorly ionizable glycosphingolipids, remains a significant challenge in mass spectrometry imaging (MSI). Herein, we report a novel MSI method that leverages a diselenide-functionalized covalent organic framework (COF–Se2) by integrating its heterogeneous catalysis and selective surface capture capabilities for on-tissue lipid capture-epoxidation, enabling the differentiation of C═C position isomers with significantly enhanced coverage for glycosphingolipids. In a finely tuned solvent environment, neutral glycosphingolipids were selectively captured and catalytically epoxidized on the COF–Se2 surface with near-quantitative efficiency (∼100%), thereby achieving their separation from epoxidized phospholipids and largely reducing ion suppression. The subsequent desorption of epoxidized glycosphingolipids for mass spectrometry (MS) analysis was allowed by switching the solvent to ammonia-methanol. Epoxidized lipids generate diagnostic fragments for the C═C position in MS/MS, with glycosphingolipids showing distinct patterns from the reported phospholipids and fatty acids. By coating COF–Se2 onto slides for tissue thaw-mounting, on-tissue capture-epoxidation was completed within 5 min. With a two-step ambient liquid extraction MS/MS imaging workflow, epoxidized phospholipids and glycosphingolipids on tissue were imaged separately in each step. Compared with the conventional method, this strategy substantially improved the lipid coverage of isomer-differentiated MSI by 7-fold in brain tissue, especially for glycolipids or sphingolipids (27 vs 0). This work illuminates the inaccessible spatial landscape of glycosphingolipid C═C isomers, opening new avenues for understanding their roles in brain function and disease.
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Yingying Qian,Houyu Yu,Qihuan He,Dandan Fan,Gerben J. Zylstra,Hancheng Wang,Xing Huang
The extensive application of cyhalofop-butyl, an aryloxyphenoxypropionate (AOPP) herbicide, for weed control in rice fields inevitably results in environmental pollution and ecological toxicity. Microbial degradation of cyhalofop-butyl is garnering immense research attention. This study revealed that Sphingobium yanoikuyae B1 can efficiently degrade the cyhalofop-butyl, completely breaking down 30 mg/L within 12 h via ester bond hydrolysis, forming cyhalofop acid. A novel hydrolase gene cbeH (37.39% identity) was identified in B1. CbeH exhibited catalytic activity by hydrolyzing the ester bond (C-O) in cyhalofop-butyl and other AOPP herbicides, yielding AOPP acids. Additionally, it catalyzed the cleavage of the C-N bond in amide herbicides propanil and diuron, as well as the C-C bond in the aromatic compound 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid. Sequence alignments and site-directed mutagenesis indicated the catalytic triad Ser-His-Asp in CbeH serves as active center cleaving C-O, C-C, and C-N bonds. Comparative analysis revealed the gene cbeH , highly conserved within Sphingomonads , was located within multiple insertion sequences on the plasmid of Rhodococcus strains. CbeH was widespread in Proteobacteria and Actinobacteria, with its host strains prevalent in aromatic-polluted environments. This study provides novel enzyme resources for remediating combined pollution and enhances our understanding of the genetic organization and environmental distribution of trifunctional pollutant-degrading genes.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2026
·
IF 10.6
Yuguo Dong,Puyan Bai,Hongyu Yang,Lin Dong,Xiaoli Gu,Changle Zhao,Zupeng Chen
Photocatalytic depolymerization of lignin into aromatic compounds is of great significance but extremely challenging, hindered by the stable interunit C-C bonds with high dissociation energies. Herein, we develop a novel oxidation acetalization strategy for the phtocatalytic cleavage of C-C bond in lignin model compounds while simultaneously reducing aldehyde condensation. Phosphorus-doped carbon nitride (Px-CN) was synthesized for the selective cleavage of Cα-Cβ bonds under visible light at room temperature. This approach achieves a nearly complete conversion (>99.9%) of 2-phenoxy-1phenylethanol, along with high yields of benzaldehyde dimethyl acetal (91.1%) and benzyl formate (56.3%). Mechanistic investigations reveal that the activation of the Cβ-H bond by photogenerated holes is crucial for the transformation to occur.Meanwhile, the introduction of phosphorus accelerates the separation efficiency of charge carriers, thereby enhancing the photocatalytic performance of the Px-CN. This work demonstrates the potential of phosphorus-doped carbon nitride for the high-selectivity photocatalytic cleavage of the C-C bond in lignin to aromatic chemicals.
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2022
·
IF 9.224
Jiayuan Sun,Shanshan Shao,Xinggang Hu,Xiaohua Li,Huiyan Zhang
The aqueous fraction of bio-oil from biomass fast pyrolysis mainly contains low-molecular-weight oxygenates such as carboxylic acids, ketones, aldehydes, phenols, and furans. In this study, the full components of aqueous bio-oil are directionally converted into carbonyl groups such as aldehydes and ketones, and then the oxygen-containing precursors of aviation fuel are prepared through coupling, focusing on exploring the mechanism of carbonylation and C–C coupling. Studies have revealed that propionic acid, furfural, and phenol can be directionally converted into ketones, in which reaction 3-pentanone, cyclopentanone, and cyclohexanone were formed via ketonization and hydrogenation in the aqueous phase. Then the two components of 3-pentanone, cyclopentanone, cyclohexanone, acetone, and acetaldehyde were subjected to aldol condensation to explore the C–C coupling mechanism in the preparation of the C7–C18 precursor of aviation fuel. The mechanism in the high-quality utilization of all components of the aqueous phase bio-oil fraction was explored, which was favorable for the synthesis of biomass-based aviation fuel.
✓ 已验证
产品关联
DOI
高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2019
·
IF 2.338
Li-ping RAN,Fei RAO,Ke PENG,Huan YIN,Mao-zhong YI
Ultrahigh-temperature ceramics were added to C/C composites to meet their application requirement in a high-temperature oxidizing environment. C/C−ZrB 2 −SiC composites were fabricated by high-solid-loading slurry impregnation with polymer infiltration and pyrolysis. The dispersion and rheological behavior of ZrB 2 slurry and the microstructural, mechanical, and ablation properties of the C/C−ZrB 2 −SiC composites were investigated. Results indicated that a well-dispersed and low-viscosity ZrB 2 slurry was obtained using 0.40 wt.% polyethyleneimine as a dispersant at pH 5. Ceramics were uniformly distributed in the short-cut fiber layer and needle-punched area. The flexural strength of the C/C−ZrB 2 −SiC composites was 309.30 MPa. The composites exhibited satisfactory ablation resistance under the oxyacetylene flame of 2500 °C, and the mass and linear ablation rates were 0.40 mg/s and 0.91 μm/s, respectively. A continuous and compact ZrO 2 layer, which could effectively reduce the diffusion rate of oxygen and protect the composites from being ablated, was formed.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2023
·
IF 6.1
Wenwen Yang,Xiaoping Zhang,Jun Zhang,Guoshuan Wang,Hailong Liang,Xinglei Zhang,Konstantin Chingin,Huanwen Chen
The positions of C═C bonds in unsaturated fatty acids (FAs) are one of the main factors determining the quality of food flavor. Herein, we developed an approach for the determination of C═C bonds of FAs by online epoxidation reaction with water dimer radical cations. The limit of detection for octenoic acid isomers was ∼9 μg/L. The positions of C═C bonds in trans-2/3-hexenoic acid, trans-2/3-octenoic acid, oleic acid, linoleic acid, and linolenic acid in black tea or olive oil samples were directly determined by the established method. These results indicate that the established method allows the rapid determination of unsaturated FAs in black tea and olive oil. The advantages of this approach include the analysis speed (∼1 min per sample), simple device, and no need for complex pretreatment. This study not only provides a strategy for the determination of C═C positions but also offers new possibilities for applications in the field of food chemistry.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）