Catalysts
·
2024
·Vol. 14
·期 2
·135
·
IF 3.8
Baofang Jin,Yuxin Liu,Yue Ma,Zhenguo Li,Kaixiang Li,Shuang Liu,Rui Ran,Xiaodong Wu
A series of Ag-modified manganese-mullite (SmMn2O5) catalysts with different Ag contents (1, 3, and 6 wt.%) were prepared via a citric acid sol–gel method for catalytic soot oxidation. The catalysts were characterized by powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Raman spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy analysis (HRTEM), X-ray photoelectron spectroscopy (XPS), and H2temperature-programmed reduction (H2-TPR). The soot oxidation activity of the mullite was significantly promoted by the addition of silver and affected by the loading amount of the metal. Herein, the influences of silver loading on the metal size distribution and its interactions with the mullite were studied. Based on these characterizations, a possible soot oxidation reaction mechanism was proposed for silver-modified SmMn2O5.
研究领域:
催化材料
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2020
·
IF 6.444
Daiqi Li,Bin Tang,Xi Lu,Wu Chen,Xiongwei Dong,Jinfeng Wang,Xungai Wang
Two independent heating steps are currently involved for fabricating carbon fiber/ceramic composites, which include carbonization of fibers and ceramization of ceramic precursors with carbonized fibers together. In this work, silk fabric and silkworm cocoon were used as carbonaceous precursors for fabricating carbonized fiber/ceramic composites through one-step heating processing. This one-step manufacturing method achieved both the carbonization of silk fabric/silkworm cocoon and the formation of mullite simultaneously under nitrogen environment. The as-prepared composite based on three-layer silk fabric reached over 100 °C after 30 s when a voltage of 10 V was applied, and achieved a stabilized temperature of 239 °C after 540 s. The obtained composites also showed stable cyclic heating property, homogeneous heat distribution and electromagnetic shielding properties. These results implicate the great potential for the developed silk-ceramic composites and inspire the further design of silk-based materials for electro-thermal conversion.
研究领域:
材料科学
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能源工程
·
纺织科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Baofang Jin,Baohuai Zhao,Shuang Liu,Zhenguo Li,Kaixiang Li,Rui Ran,Zhichun Si,Duan Weng,Wu Xiaodong
The mullite SmMn 2 O 5 (SMO) was modified with silver for soot oxidation by two methods, i.e. sol-gel (Ag/SMO-sg) and impregnation (Ag/SMO-im). The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectrometry (ICP-AES), H 2 -O 2 titration, H 2 temperature-programmed reduction (H 2 -TPR), CO temperature-programmed reduction (CO-TPR), soot temperature-programmed reduction (soot-TPR), O 2 temperature-programmed desorption (O 2 -TPD), cycled H 2 temperature-programmed reduction (cycled H 2 -TPR), NO temperature-programmed oxidation (NO-TPO) and soot temperature-programmed oxidation (soot-TPO). Metallic silver nanoparticles were observed in the mullite matrix for both the catalysts. For Ag/SMO-sg, the possible incorporation of silver into the mullite crystal cell and strong electronic interaction between the highly dispersed metal and the support increase the Mn 4+ /Mn 3+ ratio and create more structural defects in the mullite, resulting in boosted NO oxidation and thereby NO 2 -assisted soot combustion. The introduction of Ag can promote the generation/regeneration of active oxygen, which accelerates the ignition of soot in O 2 at low temperatures. Therefore, the sol-gel-synthesized Ag/SmMn 2 O 5 is highly promising for application in diesel particulate filters.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2023
·Vol. 106
·期 2
·616-625
·
IF 2.5
Wang Xuan,Qian Junjie,He Chao,Shui Anze,Du Bin
Al-doped-SiOC ceramics were fabricated via condensation polymerization and then pyrolysis of preceramic precursor in this study. The Al cation induced the formation of mullite, SiO 2 and graphitic carbon. Results showed that the incorporation of Al element enhanced the thermal stability of SiOC ceramics under Ar atmosphere via suppressing carbothermal reduction. This was consistent with the observation from Raman spectra by curve-fitting according to the D-to-G peak intensity ratio. In addition, the thermal stability of the SiAlOC ceramics under air atmosphere was also investigated. The formation of the mullite phase under the air atmosphere indicated that the SiAlOC ceramics possessed better oxidation resistance properties than the pure SiOC ceramics. This work provides a new guide to fabricating metal-modified SiOC ceramics with desired structures. Graphical Abstract
The introducing Al element greatly enhanced the thermal stability of SiOC ceramics via restraining in-situ formation of SiC. The structural evolutions of Al cation-modified-SiOC ceramics both in argon and air atmospheres were investigated systematically.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2017
·Vol. 82
·期 3
·718-727
·
IF 1.575
Wei Heng-yong,Li Hui,Cui Yi,Sang Rong-li,Wang He-yang,Wang Peng,Bu Jing-long,Dong Gui-xia
Abstract Mullite nanofibres with excellent flexibility and high temperature resistance were fabricated by electrospinning method using the nonhydrolytic sol as a precursor. The nonhydrolytic mullite sol exhibited favourable organosolubility and spinnability, due to the residual organic groups in gel particles. The thermal decomposition behaviour, crystallisation development and microstructure evolution of electrospinning precursor fibres were investigated. Results showed that the flexible mullite nanofibres with smooth surface, uniform diameter and small crystal grain size were obtained after the precursor fibres were calcined at 1000 °C for 1 h. In addition, the results also revealed that the mullite nanofibres calcined at 1500 °C still maintained their general fibrous morphology, and thereby they had the potential application in high-temperature industrial and aerospace field. Graphical Abstract
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Hengyang Mao,Hengqi Shi,Zhijie Zhang,Shouyong Zhou,Minghui Qiu,Mingmin Jia,Meisheng Li,Yijiang Zhao,Shanshan Xia,Zhentao Wu
Ceramic membranes have drawn attention in oil-in-water (O/W) treatment due to natural hydrophilicity and excellent chemical stability, however their application was restricted by high cost. In this work, a cost-effective Al 2 O 3 -based ceramic support was prepared at sintering temperature of 1500 °C with low-cost mixed-dimensional attapulgite (MDATP) as aid. The composite support with addition of 10 wt% MDATP and 3 wt% powdered carbon possessed an average pore size of 3 µm, bending strength of 63.7 MPa, pure water permeability of 1.32 × 10 4 L·m −2 ·h −1 ·bar −1 . Mullite was formed due to the reaction between Al 2 O 3 and SiO 2 in MDATP during sintering, which played a key role in preparing support with corrosive resistance performance. Then, a superwetting microfiltration (MF) membrane with pore size of 0.18 µm and permeability of 1470 L·m −2 ·h −1 ·bar −1 was obtained by coating ATP nanofiber on the Al 2 O 3 -MDATP support with sintering temperature of 600 °C. The molecular dynamics results showed that the ATP can repel oil fouling with interaction energy of − 872 Kcal·mol −1 . The excellent O/W emulsion separation efficiency of the MF membrane further demonstrated the feasibility of ATP and its by-products in decreasing membrane cost and improving performance.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2023
·
IF 6.9
Jinzhong Wu,Jiawei Du,Jiangbo Wu,Xiaoze Du
The coatings with different thermodynamic and optical properties can adjust and improve the overall performance of solid particles in solid particle solar receivers (SPSRs). In this work, the manganese iron black (PBK26) coating is prepared by water bath method and comprehensive performance of the coating is found to be the best when Fe/Mn molar ratio in PBK26 is 4:1. The high temperature radiation absorption performances of different solid particles coated by PBK26 are investigated. The results show that the spectral absorptivity of particles can be greatly improved by coating. The average spectral absorptivity of quartz sand , bauxite and mullite increases by 25.9%, 20.8% and 16.2%, respectively. However, the coated quartz sand appears coating shedding phenomenon at high temperatures, and the coating on bauxite is not complete. Only the coated mullite shows excellent coating effect and thermal stability. After long-period high temperature thermal stability experiments at 900 °C and cyclic thermal stability experiments of 30 cycles, the maximum mass loss of coated mullite is less than 0.4% and the spectral absorptivity is almost unchanged. In the wear resistance experiments the surface debris of the coated mullite increases. And there is a mass loss of 8.244% with a coating thickness loss of 27% and a spectral absorptivity decrease of 3.88% after 10 h of wear at 900 rpm. The results imply good high temperature thermal stability and acceptable wear resistance of PBK26 coated mullite, which provide an option for high temperature radiation improvement of solid particles.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 3.7
Liqin Tang,Xiang Jin,Bing Gao,Xuechao Gao,Xuehong Gu
Due to the low transport resistance, mullite hollow fiber (HF) could be regarded as a promising support for preparation of NaA zeolite membranes. However, insufficient coverage and undesired seed penetration often occur in the seeding step of the mullite support due to the rough surfaces with ultra-large macropores (2–4 μm). This leads to poor intergrowth of the membrane layer. To solve this issue, cationic polyacrylamide (CPAM) was employed to modify the chemical and electrostatic properties of the mullite HF surface, where the electrostatic attraction between the surface and seed crystals could significantly promote the coating effect. In the seeding, the original seeds (3.2 μm) were mixed with the ball-milled seeds (0.3 μm) to improve the seed coverage, i.e., the original seed was used to block the macropores on the support surface to prevent the penetration of small seeds, while the decked ball-milled seed was used to provide sufficient active sites to induce the intergrowth of the zeolite crystals. The effects of the concentration of CPAM, mixed mass ratio of seeds, and seed concentration on the preparation of NaA zeolite membranes were systematically examined, where the separation performances were characterized by pervaporation (PV) dehydration of 90% (mass) ethanol/water mixtures at 75 °C. The results indicated that under a CPAM concentration of 0.7% (mass), an equivalent mass ratio of mixed seeds in a seed concentration of 1.0% (mass), the prepared mullite HF supported NaA zeolite membrane yielded the best PV performance, where the permeation flux and separation factor corresponded to 5.45 kg·m −2 ·h −1 and 10000, respectively, being sufficient for industrial applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Chuankun Yin,Qianna Xia,Jiao Zhou,Bowen Li,Yu Guo,Aimal Khan,Xiaoxia Li,Aihua Xu
The development of efficient and eco-friendly Mn-based catalysts for peroxymonosulfate (PMS) activation and revealing the mechanism are highly desired for pollutants removal in wastewater. In this study, a ternary mullite oxide YMn 2 O 5 (YMO) was synthesized for bisphenol A (BPA) degradation in the presence of PMS for the first time. Combined with XPS, EPR and TG, abundant surface labile oxygen species (O lab ) with a ratio of 39.7% were identified in the mullite materials, which was higher than that for α-, β-, γ- and δ-MnO 2 . YMO also exhibited higher interfacial conductivity and stronger interactions among the catalyst, PMS and BPA than other MnO 2 . Superior performance in BPA degradation was observed with YMO, and O lab was suggested as the main active sites, for the normalized first-order rate constant was linearly dependent on the ratio of the oxygen species. Chemical quenching experiments, EPR and open circuit potential suggested that the degradation of BPA was mainly caused by the direct electron transfer process through the reactive O lab -PMS complexes. The influence of YMO concentration, PMS concentration, solution pH, different anions and reaction temperature was thoroughly studied. Moreover, the intermediates were identified and the possible degradation pathways were proposed. This work demonstrated that mullite oxide YMO with enriched O lab species can be used as eco-friendly catalysts for efficient PMS activation to remove recalcitrant organic compounds in wastewater.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
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