ACS Sustainable Chemistry & Engineering
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2017
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IF 5.951
Yu Guo,Junma Zou,Xiao Shi,Patrick Rukundo,Zhou-jun Wang
A nanocomposite Ni/CeO2–CDC-SiC catalyst which consists of highly dispersed Ni nanoparticles contacting intimately with CeO2 nanoparticles on a nanoporous carbide-derived carbon (CDC) layer over SiC support has been successfully designed for carbon dioxide (CO2) reforming of methane. In comparison with the Ni/CDC-SiC catalyst, the ceria-promoted Ni/CDC-SiC catalyst possessed enhanced activity and improved stability. The catalysts were systematically characterized with N2 sorption, X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectrometry elemental mapping, thermogravimetric/differential thermal analysis, temperature-programmed reduction, and X-ray photoelectron spectroscopy measurements. It was found that, after introducing CeO2 promoter, the specific surface area was increased, and a smaller Ni particle size was obtained. The smaller Ni particle size led to an enhanced reforming activity. The presence of abundant Ni–CeO2 interfaces on the CeO2-promoted catalyst accelerated the carbon removal through the lattice oxygen species, which resulted in superior carbon resistance and thus an improved stability. The outcome of the present work is expected to shed meaningful insight into the design of nanocomposite catalysts with the aid of metal–oxide interfaces.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2026
·Vol. 37
·期 14
·1107
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IF 3.2
Xu Chengjie,Shang Ning,Chen Baijun,Yang Ningtong,Song Zhi,Pan Zhigang,Tao Yaqiu,Wang Lixi
Metal–organic frameworks (MOFs) and their derivatives have attracted extensive attention due to their multiple microwave attenuation mechanisms. However, challenges such as poor impedance matching and narrow absorption bandwidth still require further research and development. In this work, we propose an in-situ growth strategy to integrate MOFs with silicon carbide nanowires (SiC NWs) using dimethyldimethoxysilane as a molecular bridge. This strategy enables the fabrication of a novel heterostructure composite inspired by Pocky biscuits, consisting of MOF and SiC nanowires, with remarkably enhanced microwave absorption properties. The unique heterostructure not only preserves the excellent dielectric properties of SiC NWs but also incorporates FeCo magnetic nanoparticles and a conductive carbon network derived from MOFs, achieving superior impedance matching and multi-polarization loss. Calcined at 700 ℃, the MOF/SiC NWs composite exhibits an effective absorption bandwidth (EAB) of 6.18 GHz, covering the 11.82 to 18 GHz range that spans the entire Ku-band at a thickness of 2.1 mm. Furthermore, it achieves full-band absorption in the X-band at 2.9 mm. The performance enhancement is ascribed to the collaborative contribution of multiple mechanisms, including interfacial polarization, magnetic resonance, and conduction loss, as revealed by experimental and theoretical analyses. The findings herein open a feasible avenue for designing MOF-based absorbing materials with precisely adjustable electromagnetic properties.
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APPLIED ENERGY
·
2022
·
IF 11.446
Boshu Jiang,Bachirou Guene Lougou,Hao Zhang,Boxi Geng,Lianxuan Wu,Yong Shuai
The solar-driven thermochemical CO 2 -to-CO conversion is an effective way to achieve the mission of carbon peaking and carbon neutrality. However, synthesizing porous reacting materials with excellent thermal stability, hardness and long-term cyclic stability, oxygen exchange capacity, and higher CO 2 -to-CO conversion are the most important challenges associated with the thermochemical CO 2 -splitting approach and technological upscaling to large-scale applications. This study presented the development of NiFe 2 O 4 oxygen carriers, the synthesis method of SiC and Si 3 N 4 supports, and solar-to-fuel processing of the newly prepared materials through CO 2 -splitting under a highly concentrated solar radiative heat flux. The newly synthesized NiFe 2 O 4 @SiC porous redox material resulted in higher solar energy absorption and CO 2 conversion capability with an instantaneous CO production of 410 μmol/g and direct CO 2 -to-CO conversion rate of 18.1 % at 1073–1273 K reaction temperature. The media composite of NiFe 2 O 4 @SiC exhibited high-temperature thermal changes, good thermochemical reaction stability, and a higher CO production rate through six redox cycles compared to NiFe 2 O 4 @Si 3 N 4 porous reacting material. The high oxidation potential and remarkably solar radiative heat flux absorption and thermochemical CO 2 -splitting capacities of the newly developed materials were demonstrated through experimental analysis. The synergistic effect of the oxygen carriers (NiFe 2 O 4 ) and substrate materials including SiC and Si 3 N 4 skeletons for CO 2 -splitting is highlighted. This study provided comprehensive and novel experimental insights that can be used as guidance for theoretical research and application in CO 2 conversion into high-value-added energy products.
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高影响因子
Journal of Materials Research and Technology-JMR&T
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2022
·
IF 6.267
Debao Liu,Zhiliang Zhou,Yiguang Wang,Baosheng Xu
SiC ceramic aerogels (CAs) with lightweight and high specific surface area have been synthesized through a sol-gel/freeze-drying technique combined with a polymer-derived ceramics (PDCs) method. The phase composition and micro-structure of the as-prepared SiC CAs were systematically characterized by a series of techniques. The results showed that the SiC CAs possess three-dimensional (3-D) network porous structure with low density, and high porosity. Meanwhile, the formation mechanism and evolution process of the SiC CAs were discussed. As applications, the electromagnetic wave (EMW) absorption properties were characterized and showed that the optimal RL can reach −26.5 dB at 11.98 GHz with thickness of 2.5 mm and its EAB is 5.4 GHz in the range of 9.6–15.0 GHz. In addition, a possible EMW absorption mechanism was also explored. The excellent EMW absorption properties endow the as-prepared SiC CAs promising materials employed in the fields of EMW absorption applications.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2022
·
IF 6.364
Sai Li,Zhongliang Lu,Haitian Zhang,Zichao Ai,Yang Ran,Yanzhen Li,Xin Deng,Dichen Li
In order to simultaneously improve both the solid loading and rheological behavior of ceramic ink during direct ink writing (DIW) process, the polyelectrolyte complexes have been used as rheological modifiers. Based on the Funk-Dinger function, the maximum solid loading of multi-sized SiC ink reached 63 vol%. The viscoelasticity of SiC inks with different [COOH]:[NH x ] molar ratios was investigated and the mechanism of polyionic chains on rheology was analyzed. When the [COOH]:[NH x ] molar ratio was 1:0.1, the SiC ink exhibited excellent thixotropic behavior and formability. The effect of particle size on rheological behavior of SiC ink was investigated to clarify the correlation between polyelectrolyte complexes and multi-sized SiC.
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jiayi Wang,Shuhang Hu,Qi Tang,Jian Xu,Nianxi Xu,Shansheng Yu,Xiaoyi Wang,Hongwei Tian
Currently, to solve the problem of electromagnetic radiation, it is imperative to develop a thin, lightweight absorber, with a wide bandwidth and an excellent absorption ability. In this study, SiC and CoFe 2 O 4 were combined on reduced graphene oxide (rGO) with immobilized rGO and SiC nanoparticles and varying amounts of CoFe 2 O 4 nanoparticles . A facile one-pot hydrothermal technique was employed to prepare four rGO/SiC/CoFe 2 O 4 composite samples with varied CoFe 2 O 4 concentrations. The electromagnetic properties of rGO/SiC/CoFe 2 O 4 composites were affected by CoFe 2 O 4 content, and CoFe 2 O 4 content was varied to change the electromagnetic properties of composites. The rGO/SiC/CoFe 2 O 4 composite samples were prepared at a graphene oxide (GO) mass of 0.5 g, SiC mass of 0.25 g, and CoFe 2 O 4 mass of 1.5 g, and this composite sample exhibited the best microwave absorption consumption. At 60 wt% of rGO/SiC/CoFe 2 O 4 composite sample, the RL min at 7.4 GHz with a thickness of 2.43 mm was −62.39 dB, and efficient absorption of broadband (EAB) was 1.4 GHz (6.8–8.2 GHz). The EAB was 3.2 GHz (11.8–15 GHz), and the RL min was −59.77 dB at 13.2 GHz with a thickness of 1.39 mm. The RL min at 17.2 GHz was −65.49 dB, and the EAB was 2.3 GHz (15.7–18 GHz), despite a thickness of only 1.06 mm. The rGO/SiC/CoFe 2 O 4 composite comprised carbon materials, magnetic metals, and semiconductors. High-performance microwave absorption was achieved by the introduction of more than one loss mechanism and coordination and supplementation of multicomponent functions. The proposed carbon/semiconductor/magnetic composite material provides a feasible solution for the preparation of excellent microwave absorbing materials in the future.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Junxian Gao,Lingling Tang,Zhizhang Shen,Yuming Dong,Zhenyu Wang,Jinze Lyu,Ji Li,Han-Qing Yu
The coupling of solar energy conversion and catalytic ozonation is an effective way to eliminate volatile organic compounds with high-efficiency and low-energy-consumption. In this work, we presented a non-noble-metal SiC/CeO 2 system for solar-light-assisted catalytic ozonation of toluene. Temperature and light-controlled experiments and atmosphere surface photovoltage measurement were conducted to evaluate photothermal and photoelectric processes. Results show that toluene removal and mineralization efficiencies of 25%SiC-CeO 2 were 69.7% and 67.1%, respectively, under full-spectrum illumination with an hourly space velocity of 6000 /h. The SiC enhanced the conversion of incident visible and infrared (IR) light to heat, thereby increasing the reaction temperature over 25%SiC-CeO 2 . Moreover, SiC transferred electrons to CeO 2 in 25%SiC-CeO 2 , generating more surface Ce 3+ sites and promoting charge carriers separation efficiency. Given these characteristics, 25%SiC-CeO 2 exhibited outstanding performance in toluene mineralization, even better than Pd-loaded CeO 2 .
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Materials
·
2022
·Vol. 15
·期 12
·4242
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IF 3.748
Xishi Wu,Qing Huang,Yunzhou Zhu,Zhengren Huang
In this study, the joining of silicon carbide (SiC) ceramics was achieved via a Si–C reaction bonding method using the phenolic resin (PF)–MgCl2system as the carbon precursor. Specifically, by adding MgCl2to the phenolic resin mixture, the average pore size of the product of carbonization of the PF resin mixture increased from 14 ± 5 nm to 524 ± 21 nm, which was beneficial for the infiltration of molten silicon at high temperature. The microstructure of the joined specimens and the effect of the inert filler on the joint strength were investigated. It was demonstrated that SiC–SiC joints with strong interfacial bonding and high flexural strength could be obtained by the Si–C reaction bonding method using a phenol formaldehyde resin/alcohol sol-gel system as the carbon precursor. The flexural strength of the joined specimens reached the highest value, i.e., 308 ± 27 MPa when the solid loading of the inert filler was 26%. Overall, stable joining of silicon carbide ceramics was achieved by the proposed method, which has significance for realizing the preparation of complex-shaped or large silicon carbide ceramic parts.Keywords:SiC ceramic;joining technology;MgCl2;phenolic resin/alcohol carbon precursor;grains and interfaces
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PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Qi Song,Zhao-Hui Zhang
As a kind of structural ceramic , ultrahigh hardness B 4 C ceramics are sensitive to flaws, especially surface flaws , which cause mechanical property degradation. The present study intended to achieve flaw self-healing with the pre-oxidation treatment method at 1073 K for 15–60 min, which effectively improved the flexural strength of the B 4 C– TiB 2 – SiC composite ceramic. The changes in surface morphology and flexural strength over pre-oxidation time were studied in detail, and schematic diagrams of pre-oxidation strengthening process were systematically proposed. The research results indicated that the pre-oxidation treatment could heal pores and cracks because glassy oxide B 2 O 3 , which has a low melting point, could flow and fill flaws on composite ceramic surfaces efficiently and, in turn, significantly improve mechanical performance. The flexural strength of the composite ceramic reached a maximum of 684 MPa at the optimum pre-oxidation time of 45 min, which was an increase of 28.77% compared with that of the untreated composite ceramic. Further increasing the pre-oxidation time resulted in a decrease in flexural strength due to pores forming on surfaces again, which was induced by the production of more CO gas and the intensive evaporation of the B 2 O 3 glass phase.
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高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2022
·
IF 4.865
Jingjing Ma,Chaoyang Cai,Jiawei Xie,Wenming Guo,Hang Qin,Jingxiong Liu,Wen Xie,Pengzhao Gao,Hanning Xiao
The low coefficient of thermal expansion (CTE) coating was designed for SiC oxidation-resistant applications by using Al 2 O 3 and LiAlSiO 4 as positive and negative expansion materials. The CTE value, relative density and flexural strength of LiAlSiO 4 -Al 2 O 3 coating were characterized. The effect of LiAlSiO 4 -Al 2 O 3 coating on the oxidation resistance and flexural strength of SiC substrate was systematically studied by cyclic oxidation tests at 1400 °C. Results showed that LiAlSiO 4 -Al 2 O 3 coating with 20 wt% LiAlSiO 4 exhibited optimal properties, featuring the excellent relative density of 93.14 %, appropriate CTE of 5.815 × 10 −6 /°C, and high flexural strength of 56.35 MPa. The weight gain of the SiC with LiAlSiO 4 -Al 2 O 3 coating was 0.49 % after 100 h of oxidation, much lower than 2.25 % of bare SiC substrate, indicating that LiAlSiO 4 -Al 2 O 3 coating effectively hindered the diffusion of oxygen and improved the oxidation resistance of SiC substrate. Moreover, the dense coating blunted defects on the SiC substrate surface, which maintained the high strength of the coated SiC after long periods of oxidation.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Guanjie Zeng,Xin Li,Yanjing Wei,Tong Guo,Xiaozhong Huang,Xuelong Chen,Xiu-Zhi Tang
Porous ceramic materials with high electromagnetic absorption capacity, low density, high thermal resistance and excellent mechanical properties are highly desirable in aerospace applications. Here, we synthesized one type of hierarchical SiC composite foams with in situ grown Si 3 N 4 nanowires via a pyrolysis process. The existence and structure of Si 3 N 4 nanowires were characterized by multiple techniques and analysis revealed that the growth of nanowires was based on a typical vapor-solid mechanism. Owing to the presence of a large amount of Si 3 N 4 nanowires, both the mechanical performance and electromagnetic absorption were significantly enhanced. The minimum Reflection loss (RL) of 1.25 mm SiC composite foam reaches −50.3 dB at 16.48 GHz with an effective bandwidth (RL < −10 dB) of 3.6 GHz (14.4–18 GHz), while the toughness and specific compressive strength increased by 356% and 126%, respectively. Especially, a ductile and steady fracture behavior was observed for the mechanically enhanced composite foam, rather than the typical catastrophic failure usually seen for ceramic materials. Owing to the excellent electromagnetic wave absorption capability and enhanced mechanical properties, as well as low density and high thermal resistance, this type of composite ceramic material may find applications in aviation, aerospace and other extreme environments.
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高影响因子
International Journal of Precision Engineering and Manufacturing
·
2021
·Vol. 22
·期 5
·951-963
·
IF 2.106
He Yan,Yuan Zewei,Song Shuyuan,Gao Xingjun,Deng Wenjuan
Photocatalysis-assisted chemical mechanical polishing, in which the photocatalysis oxidation and silica abrasives polishing are combined, is a novel finishing technique for 4H–SiC wafer. This paper characterizes the effect of pressure and abrasives on the MRR and surface quality and discusses mechanical and chemical interaction based three slurries that resulted in maximum material removal rate (1.18 μm/h) with PCMP slurry. The polished silicon carbide wafer was examined with atomic force microscope, transmission electron microscope and X-ray photoelectron spectroscopy for surface quality and material removal mechanism. The results show that an atomically smooth and flat 4H–SiC (0001) surface (Ra about 0.247 nm) was obtained by PCMP. The interface of crystal and amorphous layer of 4H–SiC wafer was flat without introducing crystallographic subsurface damage, and the atoms and lattice fringes of the crystal layer are arranged in regular order. The existence of a thin silicon oxycarbide layer, which are various forms of functional groups such as Si–C, Si–C–O, Si–O, Si 4 C 4 O 4 , C–O, and C = O, at the interface. And, it also demonstrates that the amorphous layer is composed of oxide layer (4–6 nm) and distorted layer. The silicon carbide surface is mechanically activated, oxidized and mechanically removed in turn, which is the main method of material removal.
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