RSC Advances
·
2014
·Vol. 4
·期 51
·26804-26809
·
IF 3.708
Liang Ren,Fan Yang,Yongfeng Li,Ting Liu,Liqiang Zhang,Guoqing Ning,Zhichang Liu,Jinsen Gao,Chunming Xu
We report an environmentally-friendly approach to the synthesis of hybrids based on porous graphene and metal nanoparticles. The nitrogen-doped porous graphene (N-PG) and Pd nanoparticles decorated N-PG (Pd/N-PG) was synthesized by a plasma method. The N-PG was characterized by X-ray photoelectron spectroscopy and Raman spectroscopy, and the results clearly indicate that the amount of nitrogen doping was 6.65 wt%. The synthesized Pd/N-PG hybrid materials were confirmed by transmission electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy mapping. The hybrid material based on Pd/N-PG as a new catalyst was applied in Suzuki reaction. This catalyst offers a number of advantages such as high stability, easy removal from the reaction mixture and reusability with minimal loss of activity, showing better performance than the well-known commercial Pd/C catalyst.
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Journal of Materials Research and Technology-JMR&T
·
2025
·
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.
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Surfaces and Interfaces
·
2024
·
IF 5.7
Wenhao Du,Fanhao Zeng,Yafang Gao,Ziwei Wang,Meiyan Chen,Zhi Li
Increasing the high-temperature anti-oxidation time of Carbon/carbon(C/C) composites faces significant challenges for conventional coatings. Herein, a unique bi-layer coating of HfC-TaC-B 4 C-SiC(HTBS)/ZrSiO 4 -glass(ZA) was proposed and prepared through slurry sintering method, and their oxidation behavior and mechanism were investigated. The results show that after oxidation at 1673 K in air for 750.5 h, the mass loss of the coated C/C was only 3.48% with about 720 h of weight gain oxidation, indicating that the anti-oxidation time has increased by two or three times compared to traditional coatings. The improved oxygen resistance performance was mainly attributed to the hinder layer of Si/Hf-Ta-Si-O during oxidation, which grew with the simultaneous carbothermal reduction reaction of SiO near matrix and oxidation reaction of HTBS. This is beneficial to lowering the thermal mismatch of coating system, reducing the connected thermal stress cracks as oxygen permeation channels. Our findings provide a new insight on improving the long-time thermal protection performance of C/C composites.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Fei-Feng Mao,Yi-An Wang,Yan Zhou,Ming-Shuai Sun,Wei Hui,Duan-Jian Tao
The efficient and selective conversion of biomass-derived vicinal diols into high-value-added chemicals represents a pivotal area of research that has garnered substantial interest within the scientific community. In this work, three ultralow loading Fe supports on N-doped carbon nanosphere catalysts (Fe@NC-T) were successfully prepared using the hard template method with acid etching. The selective conversion of vicinal diols into aldehydes, ketones, and amines over the Fe@NC-800 nanosphere catalyst was achieved through an anaerobic cleavage of C–C bonds and successfully utilized autologous hydrogen resources. The exceptional catalytic activity of the Fe@NC-800 nanosphere catalyst may be credited to the presence of highly dispersed Fe species at the active sites, which has been verified through several characterization techniques, control tests, and density functional theory calculations. In addition, the Fe@NC-800 nanosphere catalyst also demonstrated its wide applicability and excellent reusability under the operating conditions. We believe that this study presents an auspicious scheme for the highly selective conversion of vicinal diols into high value-added carbonyl compounds and amine products.
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ANALYTICAL CHEMISTRY
·
2017
·
IF 6.32
Yaoyao Zhao,Hansen Zhao,Xu Zhao,Jia Jia,Qiang Ma,Sichun Zhang,Xinrong Zhang,Hitoshi Chiba,Shu-Ping Hui,Xiaoxiao Ma
Unsaturated fatty acids (FAs) serve as nutrients, energy sources, and signaling molecules for organisms, which are the major components for a large variety of lipids. However, structural characterization and quantitation of unsaturated FAs by mass spectrometry remain an analytical challenge. Here, we report the coupling of epoxidation reaction of the C═C in unsaturated FAs and tandem mass spectrometry (MS) for rapid and accurate identification and quantitation of C═C isomers of FAs in a shotgun lipidomics approach. Epoxidation of the C═C leads to the production of an epoxide which, upon collision induced dissociation (CID), produces abundant diagnostic ions indicative of the C═C location. The total intensity of the same set of diagnostic ions for one specific FA C═C isomer was also used for its relative and absolute quantitation. The simple experimental setup, rapid reaction kinetics (<2 min), high reaction yield (>90% for monounsaturated FAs), and easy-to-interpret tandem MS spectra enable a promising methodology particularly for the analysis of unsaturated FAs in complex biological samples such as human plasma and animal tissues.
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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.
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JOURNAL OF MATERIALS SCIENCE
·
2023
·Vol. 58
·期 22
·9196-9209
·
IF 4.5
Tang Zhen-xiao,Yi Mao-zhong,Zhou Yuan-ming,Liu Rui-zhi,Peng Ke
A three-dimensional orthogonal woven C/C-SiC composite was successfully prepared by high-solid-loading slurry impregnation combined with precursor infiltration and pyrolysis. The microstructure, mechanical properties and ablation behavior of the C/C-SiC composite were investigated. The slurry impregnation and the precursor infiltration and pyrolysis acted as fast filling and supplementary densification, respectively. Based on a three-dimensional orthogonal woven C/C preform, the C/C-SiC composite had excellent mechanical properties with bending strength and fracture toughness of 364.46 and 22.86 MPa·m 1/2 . The mass and linear ablation rates of the C/C-SiC composite were 3.21 mg/s and 4.93 μm/s, respectively, after ablation under an oxyacetylene flame for 300 s. The good ablation performance was attributed to the passive oxidation of SiC at high temperature and high oxygen partial pressure, and the pitting caused by SiO 2 accelerated the failure of carbon fibers.
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CHINESE JOURNAL OF CATALYSIS
·
2026
·
IF 17.2
Yixin Li,Jianhao Qiu,Guanglu Xia,Qiying Liu,Biyao Fang,Meng Liu,Chen Chen,Jianfeng Yao
The selective cleavage of C α –C β bonds is of great significance to lignin valorization, and photocatalysis offers an eco-friendly pathway to achieve this process. Here, graphitic carbon nitride (g-C 3 N 4 ) modified with hollow tubular In 2 O 3 was constructed via the calcination method for the photocatalytic cleavage of lignin C α –C β bonds. MIL-68(In) was used as the precursor of In 2 O 3 , imparting a unique hollow tubular structure and a relatively large specific surface area. The hollow tubular structure is helpful for light penetration and scattering, as well as rapid migration of the lignin substrate. The Z-scheme g-C 3 N 4 /In 2 O 3 heterojunction exhibited 92.1% conversion (corresponding benzaldehyde yield: 82.4%) of the lignin model compound 2-phenoxy-1-phenylethanol (PP-ol), outperforming pure In 2 O 3 and g-C 3 N 4 by 40- and 2.3-fold, respectively, under 395 nm light illumination. By varying the illumination wavelength, the conversion and yields of the g-C 3 N 4 /In 2 O 3 composites were found to follow wavelength-dependent reactivities. Additionally, photogenerated holes are capable of converting PP-ol into benzoic acid, whereas 1 O 2 mainly converts PP-ol into benzaldehyde. This work could encourage the application of metal-organic frameworks in biomass conversion and provide insight into photocatalytic lignin valorization.
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PubMed
高影响因子
Polymers
·
2026
·Vol. 18
·期 11
·1398
·
IF 5.8
Jianing Zong,Kaize Si,Jingjing Li,Xiaomei Wang,Xu Zhang
SiOxanodes are highly promising for next-generation lithium-ion batteries due to their superior theoretical capacity. However, issues such as drastic volume expansion and low initial Coulombic efficiency (ICE) impede their practical use. While macroporous architectures can mitigate these challenges, traditional fabrication often depends on tedious hard templating methods and significant organic solvent consumption. In this work, we report a sustainable, emulsion-self-templated and organic solvent-free strategy to synthesize a carbon-coated 3D macroporous SiOx/C composite (3DM-SiOx/C@C). Our approach uniquely integrates radical polymerization with a water-in-oil emulsion and sol–gel process, followed by chemical vapor deposition (CVD). The 3D macroporous framework is generated via in-situ emulsion droplets acting as self-templates, effectively eliminating the need for external sacrificial templates and toxic etchants. Notably, this organic solvent-free process achieves an exceptional precursor to (precursor + organic solvent) mass ratio of 1.0, contrasting sharply with conventional methods (0.0044–0.17). The resulting hierarchical structure, characterized by interconnected macropores and a uniform carbon coating, significantly enhances structural integrity and electronic conductivity. Electrochemical evaluations reveal that 3DM-SiOx/C@C exhibits an improved ICE of 74.32% and long-term cycling stability even at a high current density of 1.0 A g−1compared to non-porous and uncoated counterparts. This integrated synthesis offers a green and scalable pathway for developing high-performance silicon-based anodes for large-scale energy storage.
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ANALYST
·
2022
·Vol. 147
·期 7
·1341-1347
·
IF 5.227
Chen-Chen Jiang,Xiao-Chong Li,Jian-Ang Fan,Jia-Ying Fu,Xu-Nan Huang-Fu,Jia-Jie Li,Ju-Fang Zheng,Xiao-Shun Zhou,Ya-Hao Wang
The electroreductive cleavage of carbon–halogen bonds has attracted increasing attention in both electrosynthesis and pollution remediation. Herein, by employing the in situ electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) technique, we have successfully investigated the electroreductive dehalogenation process of aryl halides with the thiol group on a smooth Au electrode in aqueous solution at different pH values. The obtained potential-dependent Raman spectra directly reveal a mixture of the reduction products 4,4′-biphenyldithiol (BPDT) and thiophenol (TP). The conversion ratios of the C–Cl and C–Br bonds at pH = 7 are 37% and 55%, respectively. Furthermore, quantitative analysis of the intensity variations of ν(C–Cl), ν(C–Br) and aromatic ν(CC) stretching modes suggests electroreductive dehalogenation via both direct electron transfer reduction and electrocatalytic hydrodehalogenation. Molecular evidence for the C–C cross coupling process through TP reaction with benzene free radical intermediates is found at negative potentials, which leads to the increasing selectivity of biphenyl products.
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CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Chen Zeng,Mingyu Zhang,Hanwei He,Xiaodong Wang,Kai Tong,Yafeng Wang,Ping Xu,Lei Zheng,Guang Zeng,Zhean Su,Qizhong Huang
Sol-gel is a promising technology to prepare the C/C–ZrC–SiC composites. However, carbon fiber erosion caused by carbothermal reduction severely degrades properties of the composites. At present study, the addition order of carbon source during sol-gel process was optimized to improve the microstructure, mechanical property and ablation resistance of the composites. Results show that adding phenolic resin before gelation combined with deposited pyrocarbon interlayer around the carbon fibers can greatly alleviate the degradation of the C/C–ZrC–SiC composites by reducing the carbon fiber erosion. The composites thus prepared delivered the flexural strength , mass and linear ablation rates are 162.58 MPa, 0.147 mg/(cm 2 ⋅s) and 0.0098 mm/s, respectively, which are 449% higher, 9.26% lower and 38.36% lower than those of the counterpart that added phenolic resin after gelation. The excellent performance is attributed to little erosion of the carbon fibers and the dense matrix of ZrC–SiC ceramics obtained from adding carbon source before gelation during the sol-gel process.
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Small
·
2023
·Vol. 20
·期 3
·2304990
·
IF 13.3
Na Ye,Wenchao Sheng,Riguang Zhang,Binhang Yan,Zhao Jiang,Tao Fang
The splitting of the C–C bonds of ethanol remains a key issue to be addressed, despite tremendous efforts made over the past several decades. This study highlights the enhancement mechanism of inexpensive NbN-modified Pd 1 Sn 3 -NbN/C towards the C–C bonds cleavage for alkaline ethanol oxidation reaction (EOR). The optimal Pd 1 Sn 3 -NbN/C delivers a catalytic activity up to 43.5 times higher than that of commercial Pd/C and high carbonate selectivity (20.5%) toward alkaline EOR. Most impressively, the Pd 1 Sn 3 -NbN/C presents good durability even after 25 200 s of chronoamperometric testing. The enhanced catalytic performance is mainly due to the interfacial interaction between PdSn and NbN, demonstrated by multiple structural characterization results. In addition, in situ ATR-SEIRAS (Attenuated total reflection-surface enhanced infrared absorption spectroscopy) results suggest that NbN facilitates the C–C bonds cleavage towards the alkaline EOR, followed by the enhanced OH adsorption to promote the subsequent oxidation of C1 intermediates after doping Sn. DFT (density functional theory) calculations indicate that the activation barriers of the C–H bond cleavage in CH 3 CH 2 OH, CH 3 CHOH, CH 3 CHO, CH 3 CO, CH 2 CO, and the C–C bond cleavage in CH 3 CO, CH 2 CO, CHCO are evidently reduced and the removal of adsorbed CH 3 CO and CO becomes easier on the PdSn-NbN/C catalyst surface.
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