COMPOSITES SCIENCE AND TECHNOLOGY
·
2022
·
IF 9.879
Muhammad Awais,Xiangrong Chen,Zelin Hong,Qilong Wang,Yiwen Shi,Fan-Bo Meng,Chao Dai,Ashish Paramane
Epoxy (EP) resin insulations are widely used in electronic devices and power systems . They are gradually finding their way as winding insulation material for medium frequency transformers (MFT) due to their attractive insulating and adhesive properties along with low cost and easy processing. However, their dielectric insulation properties are compromised at high frequencies and high temperatures due to poor thermal properties. In this context, the surface-treated hexagonal boron nitride (h-BN) micro fillers and core-shell TiO 2 @SiO 2 nanofillers are doped in epoxy (EP) to enhance their thermal and electrical insulation properties under high frequencies and high temperatures. Results reveal that the thermal conductivity of the EP increases continually, whereas the electrical breakdown strength is reduced above the threshold content of micro/nano fillers. Particularly, the micro h-BN addition is beneficial for thermal conductivity enhancement, whereas the core-shell structure of TiO 2 @SiO 2 improves the electrical insulation properties of the EP. The multi-layer core model is used to explain the dynamics of the fillers. The homogeneous dispersion and optimal content of suitable micro-nano fillers can produce efficient EP composites as the electrical insulation for medium frequency transformers.
研究领域:
材料科学
·
电气工程
·
聚合物纳米复合材料
·
电介质与电气绝缘
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 35
·21758-21767
·
IF 3.108
Yali Bai,Zhenhuan Li,Bowen Cheng,Maliang Zhang,Kunmei Su
U–TiO2 is successfully coated with SiO2 and subsequently well modified by APTES, and the core–shell structure exists on TiO2@SiO2 and TiO2@SiO2/APTES, which greatly reduces aggregation of the TiO2 nanoparticles. The photocatalytic activities of U–TiO2, TiO2@SiO2, and TiO2@SiO2/APTES are evaluated using MB decomposition. Nearly 50% of the MB is degraded after 15 min in the presence of the U–TiO2 under UV radiation (300 W), and only 17.44% and 4.18% of the MB is degraded in the presence of the TiO2@SiO2-0.6 and TiO2@SiO2/APTES-1. However, TiO2@SiO2/APTES-0.6 and TiO2@SiO2-0.2 exhibit excellent UV absorbance capacities, and the TiO2@SiO2/APTES-0.6 achieves 80% of the UV-shielding ability of U–TiO2. Poly(p-phenylene sulfide) (PPS) is an easily photodegraded material and TiO2/PPS is more seriously photodegraded than PPS, however, the TiO2@SiO2/APTES nanoparticles can effectively protect the PPS from UV degradation, owing to their lower photocatalytic activities, higher UV-shielding abilities and easy dispersion in the PPS matrix. The breaking strength retention rate of the 1 wt% TiO2@SiO2/APTES/PPS film shows a maximum increase of 38.26%, and the breaking elongation retention rate increased by 41.64% at 2 wt% TiO2@SiO2/APTES loading. These results reveal that the incorporation of the TiO2@SiO2/APTES nanoparticles into the PPS matrix imparts excellent anti-UV properties to the PPS matrix, leading to a mechanical performance improvement.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 47
·22895-22907
·
IF 3.925
Sheng Chen,Ji-Nan He,Ying-Min Xu,Sheng-Li Chen,Ai-Jun Wang
Photocatalytic conversion of nitrogen to ammonia with water under ambient conditions is a desired strategy. In the present work, in order to increase the activity of the TiO2 photocatalyst for N2 fixation, bilayer TiO2/SiO2 opal composite membranes were prepared via coupling TiO2 films with SiO2 opal photonic crystal (PC) films, and their photocatalytic performance in nitrogen fixation was tested. It was shown that when the photonic band gap (PBG) of the SiO2 PCs matched with the UV-Vis absorption edge of TiO2, the photon localization effect of SiO2 PCs was maximized to promote the photon capture of TiO2, resulting in more photogenerated electron–hole pairs for N2 activation. The photon localization effect of SiO2 PCs is negatively correlated with the thickness of the TiO2 films in composite membranes. The nitrogen fixation activity of the TiO2/SiO2 opal composite membrane, with the thickness of TiO2 film being 700 nm, was found to be 42.6 μmol gcat−1 h−1, which was 68% higher than that of the plain TiO2 film.
研究领域:
材料科学
·
化学工程
·
催化
·
光子学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 16
·3856
·
IF 4.2
Xiaoxue Liu,Lanfen Zhang,Jian Hu,Wei Zhang,Xiaorong Xiang,Huiqing Cheng,Li Qin,Hao Li
In recent years, TiO2-based catalysts have received extensive attention from researchers for their excellent oxidative desulfurization (ODS) performances. In this paper, a series of mesoporous TiO2/SiO2catalysts with different TiO2loadings are prepared, using an incipient wetness impregnation method with agricultural waste rice husk as both the silicon source and mesoporous template and tetrabutyl titanate as the titanium source. The effect of different TiO2loadings on the ODS performance of the samples is investigated, and the appropriate TiO2loading is 2.5%. Compared with pure TiO2, the 2.5%TiO2/SiO2sample exhibits high catalytic activity for oxidative desulfurization. This is, on the one hand, due to the high specific surface area and mesopore volume of the 2.5%TiO2/SiO2sample. On the other hand, it is due to the uniform dispersion of TiO2grains with an average diameter of 6.1 nm on the surface of the mesoporous SiO2carrier, which greatly increases the active sites of the 2.5%TiO2/SiO2sample, thus improving the catalytic activity of the sample. The recycling performances of the 2.5%TiO2/SiO2sample are further investigated. The results show that, after fifteen cycles, the 2.5%TiO2/SiO2sample still maintains high conversions of dibenzothiophene (99.8%) and 4,6-dimethyldibenzothiophene (99.7%) without deactivation. In addition, the 2.5%TiO2/SiO2sample treated with TBHP aqueous solution is characterized by the technique of UV-Vis, and the Ti-peroxo (Ti-OOtBu) species, the active intermediate for the ODS of bulky organic sulfides, is successfully captured. Finally, a possible reaction mechanism for the ODS process over the 2.5%TiO2/SiO2sample is proposed.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2014
·
IF 3.107
Qing Shen,Hon-Yeung Cheung
A solid-phase extraction (SPE) procedure, using titania-coated silica (TiO2/SiO2) core–shell composites as the sorbent, combined with a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for extraction, visualization, and quantification of phospholipids in shrimp waste (Litopenaeus vannamei). The SPE protocol was optimized, and the best conditions were pH 5 of the loading solvent, 10% aqueous methanol as the washing solvent, and 1.0 mL of chloroform/methanol (1:2, v/v) as eluting solvents. Afterward, the eluate was separated on a diol hydrophilic interaction chromatography (HILIC) column. A total of 69 phospholipid species were identified and determined. The results indicated that, in comparison to previously published methods, this strategy was cost-effective and efficient in extraction, characterization, and determination of phospholipids. Meanwhile, phospholipids were abundant in shrimp waste, most of which contained unsaturated fatty acyl chains, such as 18:3 [α-linolenic acid (ALA)], 20:5 [eicosapentaenoic acid (EPA)], and 22:6 [docosahexaenoic acid (DHA)]. The successful application of this strategy paves the way for full use of traditionally discarded shrimp wastes.
研究领域:
分析化学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2023
·
IF 17.1
Tianyi Liu,Miao Yan,Shan Zhou,Qirui Liang,Yanjun He,Xin Zhang,Hui Zeng,Jian Liu,Biao Kong
Micro-/nanomotors with advanced motion manipulation have recently received mounting interest; however, research focusing on the motion regulation strategies is still limited, as the simple construction and composition of micro-/nanomotors restrict the functionality. Herein, a multifunctional TiO2-SiO2-mesoporous carbon nanomotor is synthesized via an interfacial superassembly strategy. This nanomotor shows an asymmetric matchstick-like structure, with a head composed of TiO2 and a tail composed of SiO2. Mesoporous carbon is selectively grown on the surface of TiO2 through surface-charge-mediated assembly. The spatially anisotropic distribution of the photocatalytic TiO2 domain and photothermal carbon domain enables multichannel control of the motion, where the speed can be regulated by energy input and the directionality can be regulated by wavelength. Upon UV irradiation, the nanomotor exhibits a head-leading self-diffusiophoretic motion, while upon NIR irradiation, the nanomotor exhibits a tail-leading self-thermophoretic motion. As a proof-of-concept, this mechanism-switchable nanomotor is employed in wavelength-regulated targeted cargo delivery on a microfluidic chip. From an applied point of view, this nanomotor holds potential in biomedical applications such as active drug delivery and phototherapy. From a fundamental point of view, this research can provide insight into the relationship between the nanostructures, propulsion mechanisms, and motion performance.
研究领域:
纳米技术
·
材料科学
·
生物医学工程
·
光子学
✓ 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）