APPLIED CATALYSIS B-ENVIRONMENTAL
·
2016
·
IF 8.328
Lun Pan,Tahir Muhammad,Lu Ma,Zhen-Feng Huang,Songbo Wang,Li Wang,Ji-Jun Zou,Xiangwen Zhang
ZnO is an important semiconductor that has been widely applied in solar cell, photocatalysis, environmental remediation. Doping and morphology control are important approaches to improve its photocatalytic performance. Herein, a facile two-step calcination method was developed to fabricate carbon(C)-doped cubic ZnO with porous structure from zeolite imidazolate frameworks (ZIF-8). Compared with one-step pyrolysis, the approach of two-step calcination not only retains the cubic morphology with inter-connected ZnO nanoparticles and porous structure but also introduces C doping in ZnO lattice effectively. This morphology has advantage in charge transfer, optical absorption and mass transfer during the photoreaction, and C doping results in high charge-separation efficiency. The sample C350-400 (C-doped ZnO, firstly calcined at 350 °C for 2 h from ZIF-8, then 400 °C for 1 h) shows the maximum photoactivity, which is ca . 3-fold and 4-fold higher than ZnO (C450) in photodegradation and PEC water splitting (under UV–vis irradiation), respectively. It is expected that the preparation of metal oxide from MOF is a very promising way to fabricate highly efficient photocatalyst.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2018
·
IF 2.593
Pengfei Hu,Changchun Chen,Jiawei Song,Zhonghai Tang
Specific surface area of photocatalyst usually has an important influence on its photocatalytic performance. Herein, mesoporous ZnFe 2 O 4 /ZnO nanocomposites were successfully fabricated by facile calcination methods using ZnFe 2 O 4 /ZIF-8 as the precursor. The structure, morphology, optical and adsorption properties of the as-prepared samples were detailedly characterized, and photocatalytic performances of these samples were mainly evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 400 nm). The results demonstrated that the ZnFe 2 O 4 /ZnO hybrids are of enhanced visible-light photocatalytic performances among all the samples, indicating that the heterojunction structure between ZnFe 2 O 4 and ZnO efficiently inhibited the the recombination of photogenerated electron-hole pairs. Wherein, the ZFO/C6A4 sample prepared via two-step calcination method (600 °C in Ar and then 400 °C in air ambient) possessed higher visible light photocatalytic activity than the ZFO/A6 sample prepared via one-step calcination (600 °C in air ambient). This phenomenon was probably ascribed to the lager pore volume and average pore size of ZFO/C6A4 sample. Moreover, the potential carbon doping in ZnO particles during two-step calcination process was inferred by the XRD analysis , which further facilitated the separation of photogenerated electron-hole pairs in the ZFO/C6A4 sample. On the other hand, the composite sample also exhibited good magnetic recovery property and photochemical stability. These results indicated that the ZnFe 2 O 4 /ZnO nanocomposite prepared via two-step calcination method would be quite promising for the degradation of organic pollutants.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Zhiyang Li,Yuning Mao,Qinghua Tian,Wei Zhang,Li Yang
As the concept of promoting environmental protection and energy conservation becomes more and more popular, reasonably green approaches for preparing high-performance nanostructured Fe 2 O 3 anodes will be well received. Herein, porous Fe 2 O 3 quasi-clusters assembled by smaller secondary nanoparticles have been successfully prepared by direct calcination of commercial ferric citrate in air atmosphere. Comparing with the traditionally hydrothermal methods of preparing various nanostructured Fe 2 O 3 , our approach are more facile and green because of no use of various solvents and reagents, and additional time- and power-consuming hydrothermal treatment. More importantly, the as-prepared Fe 2 O 3 quasi-clusters show excellent electrochemical performance, delivering high capacities of 1187.1 and 448.3 mAh g −1 at 200 and 3000 mA g −1 after 350 and even 1500 cycles, respectively. Even comparing with the reported state-of-the-art nanostructural Fe 2 O 3 anodes, the performance of as-prepared Fe 2 O 3 quasi-clusters is competitive and even better. Thus, due to the relatively green and extremely facile preparation process, and excellent electrochemical performance, the as-achieved Fe 2 O 3 quasi-clusters are expected as a promising candidate for advanced anode materials of lithium-ion batteries.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
Magnetochemistry
·
2022
·Vol. 8
·期 10
·118
·
IF 3.336
Yujie Yang
W-type hexaferrites were discovered in the 1950s and are of interest for their potential applications. In this context, many researchers have conducted studies on the partial substitution of Fe sites in order to modify their electric and magnetic properties. In this study, W-type SrYb hexaferrites using Al3+as substitutes for Fe3+sites with the nominal composition Sr0.85Yb0.15Zn1.5Co0.5AlxFe16−xO27(0.00 ≤ x ≤ 1.25) were successfully synthesized via the two-step calcination method. The microstructures, spectral bands of characteristic functional groups, morphologies, and magnetic parameters of the prepared samples were characterized using XRD, FTIR, SEM, EDX, and VSM. The XRD results showed that, compared with the standard patterns for the W-type hexaferrite, the W-type SrYb hexaferrites with the Al content (x) of 0.00 ≤ x ≤ 1.25 were a single-W-type hexaferrite phase. SEM images showed the flakes and hexagonal grains of W-type hexaferrites with various Al content (x). The saturation magnetization (Ms) and magneton number (nB) decreased with Al content (x) from 0.00 to 1.25. The remanent magnetization (Mr) and coercivity (Hc) decreased with Al content (x) from 0.00 to 0.25. Additionally, when the Al content (x) ≥ 0.25,MrandHcincreased with the increase in the Al content (x). The magnetic anisotropy field (Ha) and first anisotropy constant (K1) increased with the Al content (x) increasing from 0.00 to 1.25. Al-substituted W-type SrYb hexaferrites with soft magnetic behavior, highMs, and lowerHcmay be used as microwave-absorbing materials.Keywords:two-step calcination method;W-type hexaferrites;magnetic properties;X-ray diffraction
研究领域:
材料科学
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磁学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 4
·676
·
IF 4.324
Siyang Ji,Yanling Yang,Xing Li,Hang Liu,Zhiwei Zhou
A novel heterogeneous Fenton-like photocatalyst, Fe-doped graphitic carbon nitride (Fe-g-C3N4), was produced by facile two-step calcination method. This Fe–g–C3N4catalyzed rhodamine B degradation in the presence of H2O2accompanied with visible light irradiation. transmission electron microscopy(TEM), x-ray diffraction (XRD), FT-IR, x-ray photoelectron spectroscopy (XPS), and photoluminescence fluorescent spectrometer (PL) characterization analysis methods were adopted to evaluate the physicochemical property of samples. It can be observed that the Fe-g-C3N4exhibited excellent photocatalytic Fenton-like activity at a wide pH range of 3–9, with rhodamine B(RhB) degradation efficiency up to 95.5% after irradiation for 45 min in the presence of 1.0 mM H2O2. Its high activity was ascribed to the formation of Fe–N ligands in the triazine rings that accelerated electron movement driving the Fe(III)/Fe(II) redox cycle, and inhibited photo-generated electron hole re-combinations for continuous generation of reactive oxygen species by reactions between Fe(II) and H2O2. The main active oxygen species were hydroxyl radicals, followed by superoxide radicals and hole electrons. This produced catalyst of Fe–g–C3N4shows excellent reusability and stability, and can be a promising candidate for decontamination of wastewater.Keywords:Fenton-like photocatalysis;graphitic carbon nitride;two-step calcination;composite materials
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Environmental Science-Nano
·
2020
·Vol. 7
·期 12
·3814-3823
·
IF 7.683
Hanfeng Zhou,Zhibo Deng,Tianbao Liu,Tao Liu,Lijuan Zhang,Xintai Su,Zhang Lin
The science linking thermochemical conversion of large-scale industry oily sludge with applied materials has been improved in the last ten years. However, with the traditional converting methods it is hard to precisely control the composition and structure of oily sludge-based products during pyrolysis due to the complexity of the composition of the oily sludge. Here, a chlorinating calcination method using sodium chloride (NaCl) as a chlorinating salt and template was first developed to prepare porous Fe–N–C materials (FCN-500) through pyrolysis of oily sludge containing iron-bearing minerals and pyridine. The formation mechanism of FCN-500 was proposed, where iron ions (Fe3+) from the inorganic component (anorthite) in the sludge were rapidly dissociated with the assistance of NaCl, followed by coordination with the organic component (pyridine nitrogen) in the oily sludge to form the pyridine nitrogen–iron ((C5H6N)n–Fe) complex, and then carbonization. As-obtained FCN-500 exhibited higher specific capacitance (286.3 F g−1 at a current density of 0.5 A g−1), enhanced energy density (33.5 W h kg−1 at a power density of 606.1 W kg−1) and more excellent stability and durability (more than 80.1% capacitance retention after 10 000 cycles) compared with two other electrodes. The reasonably better performance of the obtained FCN-500 in supercapacitors (SCs) is attributed to its large surface area, hierarchically porous channels, high conductivity, and unique Fe–N–C structure. Therefore, this work not only provides a feasible way to solve the bottleneck problem in sludge pyrolysis, but also provides a method to design large scale porous Fe–N–C materials for practical applications.
研究领域:
环境科学
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材料科学
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能源科学
✓ 已验证
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2024
·
IF 6.1
Lisheng Deng,Shusen lin,Linfa Xiao,Mitsuhiro Kubota,Hongyu Huang,Jun Li,Dezhen Chen
The application of MgO/Mg(OH) 2 in heat storage technology has been limited due to slow hydration rate and easy agglomeration. In this paper, nanoporous carbon particle (NCP) as a carrier was used to prepare NCP/MgO chemical heat storage composite materials by impregnation and calcination methods, respectively. The microstructure characterization, hydration reaction, and simultaneous thermogravimetric analysis experiments were carried out on the prepared composite materials. The results showed that the internal distribution of MgO in the composite material prepared by calcination method was more uniform, and the particle size of MgO was smaller. Under the conditions of 110 ℃ hydration temperature and 57.8 kPa water vapor partial pressure, the hydration conversion ratio of the composite material prepared by calcination method after 120 min of hydration conversion ratio reached 93 %, which was 17.7 % higher than that of the impregnated composite material and 50 % higher than that of pure MgO. Under the comprehensive influence of specific surface area, pore structure, and active component particle size, compared with pure materials and impregnated composite materials, the dehydration rate of the composite material prepared by calcination method at 300 ℃ was twice that of impregnated method and 6 times that of pure MgO, and the heat storage density reached 1039kJ/kg. After 10 cycles, the heat storage density still maintained an initial state of 95.8 %. Compared with pure materials and impregnated composite materials, NCP/MgO composite materials prepared by calcination method had better heat storage performance and higher cyclic stability.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ciwang Quan,Xianjun Yang,Jiajun Luo,Ziqiao Wang,Yushuai Feng,Jianjun Zhang,Weihua Chen,Bingliang Liang
MoSi 2 is a promising candidate for high-temperature, structural materials. However, their oxidation resistance is poor below 600 °C. To prevent MoSi 2 from being oxidized at low temperatures, core-shell structured MoSi 2 @ZrO 2 powder were prepared by hydrothermal-calcination approach. First, MoSi 2 @Zr(OH) 4 core-shell composite powder with nano-sized Zr(OH) 4 shell particles were synthesised using a hydrothermal method . Subsequently, the MoSi 2 @ZrO 2 core-shell structured powder were obtained by calcination of the MoSi 2 @Zr(OH) 4 powders at 900 °C for 2h. Finally, microstructure and oxidation behaviour of the MoSi 2 @ZrO 2 powder at 400 °C–600 °C in air were investigated systematically. Microstructural analysis revealed that all samples had a distinct core-shell structure, and the ZrO 2 shells coated the surface of the MoSi 2 core. Oxidation behaviour studies showed that the dense ZrO 2 shell layer could isolate the MoSi 2 surface from oxygen, improving the low-temperature oxidation resistance and providing better low-temperature antioxidant properties than those of the MoSi 2 and MoSi 2 @Zr(OH) 4 core-shell structures.
研究领域:
材料科学
·
高温材料
·
氧化行为研究
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2022
·Vol. 103
·期 1
·125-138
·
IF 2.606
Ma Yunzhu,Peng Shaoheng,Liu Wensheng,Yao Shuwei,Wang Juan
Controlling the density and the nanograin size is challenging but essential to prepare continuous alumina fibers with excellent performance. In this study, the continuous alumina fibers were prepared using the sol-gel method. The fibers calcined under different conditions were characterized to reveal the effect of calcining conditions on the fiber microstructure evolution. The results show that the phase transformation from amorphous Al 2 O 3 to γ-Al 2 O 3 and then to α-Al 2 O 3 takes place during the calcining process. The fiber, prepared using a single-step calcining method, cannot obtain a fully dense and nanocrystal microstructure through optimizing the calcination conditions. Thus, a novel two-step calcining process was proposed, through which an almost fully dense α-Al 2 O 3 fiber with an average grain size of ~150 nm was prepared and the tensile strength of fibers reaches 2.2 GPa. Based on the results, the effect mechanism of residual organics, phase transformation, densifying, and grain growth on the fiber microstructure evolution was discussed in depth.
Graphical abstract
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Micromachines
·
2024
·Vol. 15
·期 7
·828
·
IF 3
Ji Li,Yu Wang,Xinyuan Pei,Chunhe Zhou,Qing Zhao,Ming Lu,Wenjuan Han,Li Wang
The ZnMn2O4/V2CTxcomposites with a lamellar rod-like bond structure were successfully synthesized through high-temperature calcination at 300 °C, aiming to enhance the Li storage properties of spinel-type ZnMn2O4anode materials for lithium-ion batteries. Moreover, even though the electrode of the composites obtained at 300 °C had a nominal specific capacity of 100 mAh g−1, it exhibited an impressive specific discharge capacity of 163 mAh g−1after undergoing 100 cycles. This represents an approximate increase of 64% compared to that observed in the pure ZnMn2O4electrode (99.5 mAh g−1). The remarkable performance of the composite can be credited to the collaborative impact between ZnMn2O4and V2CTx, leading to a substantial improvement in its lithium ion storage capacity. Therefore, this study offers valuable insights into developing cost-effective, safe, and easily prepared anode materials.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 105
·86387-86392
·
IF 3.84
F. Wang,H. L. Zhu,H. P. Zhang,H. Y. Tang,J. Y. Chen,Y. H. Guo
This study aims at manipulating the surface microstructure of polytetrafluoroethylene (PTFE) microporous materials via a novel casting–lyophilization–calcining (CLC) process. In the CLC process, the emulsion consisting of polyvinylidene fluoride (PVDF), sodium dodecyl benzene sulfonate (SDBS) and distilled water was firstly poured onto the surface of the PTFE microporous materials and then the PTFE materials covered by the emulsion were sintered after removal of the distilled water by lyophilization. The results indicate that a compact thin PVDF layer can be easily constructed on the surface of the PTFE microporous materials by controlling the wetting state transition, which can be easily handled by regulating the SDBS concentration in the CLC process. The bubble point is enhanced owing to the compact PVDF layer on the surface, leading to a higher collection efficiency. In addition, the average pore size, porosity and thickness can be easily manipulated by controlling the SDBS concentration and PVDF mass fraction. Finally, the filtration mechanism changes from depth filtration to surface filtration, which brings about a higher air flux recovery. We hope such a novel process could be potentially useful in the surface microstructure regulation of polymer microporous materials with low surface energy.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Yaru Shang,Tianxing Liu,Gang Chen,Yu Wang
In this study, nitrogen-doped carbon dots (NCDs) modified ultrathin carbon nitride (g-C 3 N 4 ) nanosheets were synthesized by a simple secondary calcination method, which realizes efficient photocatalytic hydrogen production . The secondary calcination process can not only thermally exfoliate g-C 3 N 4 into ultrathin nanosheets , but also uniformly anchor NCDs (∼3 nm) on the surface of g-C 3 N 4 . The photocatalytic results manifested that a very small amount of NCDs (0.5 wt%) loading on g-C 3 N 4 could achieve a high photocatalytic hydrogen production rate (5.21 mmol g −1 h −1 ). The reasons for the enhanced photocatalytic activity were analyzed. The ultrathin g-C 3 N 4 nanosheets facilitated the migration of photogenerated carriers . Moreover, NCDs/g-C 3 N 4 exhibited enhanced visible light absorption owing to the up-conversion fluorescence effect of NCDs and the narrow band gap caused by the decoration of NCDs. Furthermore, NCDs as electron acceptors can promote carrier separation. This combination strategy provides a basis for the synthesis of inexpensive, metal-free, and efficient carbon-based photocatalysts .
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）