JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Zhengyu Wei,Tianyi Ding,Caihe Bai,Ruisheng Zhang,Sen Yang,Wei Wei
Non-oxidative intercalation of graphite avoids damage to graphene lattices and is a suitable method to produce high-quality graphene. However, the yield of exfoliated graphene is low in this process due to the poor delamination efficiency of guest species. In this study, a Brønsted acid intercalation protocol is developed involving polyoxometalate (POM) clusters (H 6 P 2 W 18 O 62 ) as guests and intercalation of graphite is realized at the sub-nanometer scale. Theoretical simulation based on DFT elucidates the stepwise intercalation mechanism of Brønsted acid molecules and clusters. Unlike common molecules/ionic guests, intercalation of POM clusters induces large expansion and extensive donor–acceptor interactions among graphite interlayers. This significantly weakens the van der Waals forces and promotes exfoliation efficiency of graphene layers. The exfoliated graphene possesses outstanding features of large lateral size, thin thickness, and high purity, and shows excellent performance as the anode for high power sodium-ion batteries. This work proffers a new pathway toward non-oxidative intercalation of graphite for large-scale production of graphene.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Tian Zhang,Limei Pan,Huan Tang,Fei Du,Yanhua Guo,Tai Qiu,Jian Yang
Herein, enhanced exfoliation and large-scale delamination of two-dimensional (2D) Ti 3 C 2 T x MXene using etchant of HCl + LiF, instead of HF, in which both etching and intercalation were achieved in exfoliation process, were thoroughly investigated with the focus on the effects of two critical factors, reaction temperature and washing solution. Increasing etching temperature promotes the exfoliation process, i.e., the transformation from Ti 3 AlC 2 to multilayer Ti 3 C 2 T x MXene, whereas simultaneously results in an aggravated surface oxidation of MXene layers formed after the extraction of Al. As a result, delamination ratio increases firstly and then decreases, and the samples etched at 35 °C show the highest delamination ratio. Compared with the distilled water, washing the exfoliation products using ethanol significantly improves the delamination ratio of Ti 3 C 2 T x MXene by co-intercalation of larger alcohol molecule and more impurity ions and a large scale delamination of Ti 3 C 2 T x MXene with a delamination ratio as high as 29.2% was obtained by simple sonication for 1 h, without additional intercalation step required, after washing using ethanol. The possible exfoliation reactions by HCl + LiF solution were proposed. Using the as-fabricated stable suspensions of delaminated Ti 3 C 2 T x flakes, flexible, free-standing Ti 3 C 2 T x papers with tailored thickness, hydrophilic surface and excellent conductivity, typically 2 × 10 5 S/m at 5 μm in thickness, were prepared. As anode for lithium ion batteries , the delaminated Ti 3 C 2 T x MXene obtained reversible capacities of 226.3 mAh g −1 , 137.9 mAh g −1 ,102.0 mAh g −1 and 47.9 mAh g −1 respectively at the current density of 100, 300, 1000 and 3000 mA g −1 , which are superior to those of the Ti 3 C 2 MXene prepared by conventional HF process.
研究领域:
材料科学
·
能源存储
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wei Ma,Binghua Yao,Wen Zhang,Yangqing He,Yan Yu,Jinfen Niu
A novel piezocatalytic active membrane based on mixed matrix of exfoliated multi-flaw MoS 2 (E-MoS 2 ) nanosheets and polyvinylidene fluoride (PVDF) was synthesized by electrospinning technique. The composition and structure of the obtained E-MoS 2 /PVDF electrospun fiber membranes (EFMs) were characterized via FESEM, HR-TEM, XRD, FTIR and XPS techniques. The piezocatalytic activity of the EFMs was evaluated by the degradation of antibiotic oxytetracycline (OTC) under ultrasonic irradiation in the dark. The 10.0 wt% E-MoS 2 /PVDF EFMs exhibited superior OTC degradation efficiency of 93.08% within 24 min with pseudo-first-order kinetic constant ( k ) of 0.09124 min −1 , which was 21.1 times higher than that of the pure PVDF EFMs. The superior performance was attributed to the synergetic effect of the embedded E-MoS 2 nanosheets and a high proportion of PVDF β -phase (94.1%) to effectively improve the piezoelectric property of composite. In addition, the ultrathin multi-flaw structure of E-MoS 2 provided abundant catalytic active edge sites and increased the surface charge density, promoting the generation of more ∙OH and ∙O 2 – radicals to degrade OTC pollutants. The degradation intermediates of OTC over 10 wt% E-MoS 2 /PVDF EFMs were detected by HPLC–MS and two main degradation pathways were reasonably proposed. The piezocatalytic activity of 10 wt% E-MoS 2 /PVDF EFMs remained stable after five consecutive cycles. This study is meaningful for exploring the composite membrane piezocatalysts for largescale applications in wastewater treatment.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Hengrui Zhang,Yunjia Xue,Liwen Yan,Anran Guo,Haiyan Du,Jiachen Liu
Aluminum silicate fiber fabric (ASFF) has been widely used in the outer surface of flexible insulation felt on the leeward side of aerospace vehicle. In order to improve the temperature resistance of ASFF, a kind of SiC–ZrC composite coating was prepared on the surface of fiber fabric via spraying method with SiC as emittance agent and ZrC as additive. The surface morphology and mechanical properties of the coating were studied. Compared with the single-component SiC coating, the composite coating could effectively avoid coating spalling and improve the surface integrity at high temperature. After thermal treatment at 1100 °C for 2 h, the interface bond strength of the composite coating/substrate was 52.41% higher than that of SiC coating/substrate. The tensile strength of fiber fabric with SiC–ZrC composite coating could reach 91.75 MPa, which was 101.76% higher than that of raw ASFF. Therefore, the SiC–ZrC coating could greatly improve the temperature resistance of ASFF, and has an attractive application prospect in the field of thermal protection system.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
DOI
高影响因子
Advanced Composites and Hybrid Materials
·
2024
·Vol. 7
·期 1
·1-15
·
IF 23.2
Jiang Hao,Li Jindao,Xie Yuhui,Du Yirou,Zhao Junping,Mei Yi,Xie Delong
Boron nitride nanosheets (BNNS) hold significant promise as functional additives in thermal management materials for high-density and high-power electronic devices. However, due to the surface chemical inertness and strong “lip-to-lip” interactions between adjacent layers of hexagonal boron nitride, efficient exfoliation and simultaneous surface functionalization of BNNS remain a challenge. In this work, an innovative approach combines alkali-assisted hydrothermal treatment with high-speed shearing, achieving an impressive 65% yield of high-quality BNNS with a thickness of only 2.54 nm. Moreover, the hydroxyl functional groups were successfully introduced to BNNS surfaces, rendering them suitable for waterborne polyurethane (WPU) to create a multifunctional heat-conductive film. In 50-R8-BNNS/WPU film, achieved by simply mixing 50 wt% BNNS within WPU, a remarkable through-thickness thermal conductivity of 7.58 Wm −1 K −1 was attained, which is 30-fold increase compared to pure WPU. Moreover, this film exhibits remarkable thermal stability, excellent tensile strength, and fire safety performance, which is used as thermal interface materials for high-power LED and exhibits better thermal management capabilities compared to commercial silicone greases. The finding establishes a straightforward and efficient method for producing high-quality BNNS suitable for the composites of electronic thermal management applications. Graphical abstract
研究领域:
材料科学
·
纳米技术
·
高分子科学
·
热工学
·
电子封装
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Dongbo Zhang,Yue Yu,Xiaolong Feng,Zhongyuan Tian,Ruiqing Song
A pyrochlore-structured La 2 (Zr 0.2 Ce 0.2 Hf 0.2 Sn 0.2 Ti 0.2 ) 2 O 7 high-entropy oxide was designed and synthesized, and its properties were tested. Traditional two-layer structured thermal barrier coatings (TBCs) with a La 2 (Zr 0.2 Ce 0.2 Hf 0.2 Sn 0.2 Ti 0.2 ) 2 O 7 top-coat were prepared by plasma spraying . A phase-pure defective-fluorite high-entropy-oxide top coat was thus obtained. The results confirmed the possibility of synthesizing pyrochlore-structured La 2 (Zr 0.2 Ce 0.2 Hf 0.2 Sn 0.2 Ti 0.2 ) 2 O 7 . The material exhibited a low thermal conductivity , which increased with increasing temperature. The coefficient of thermal expansion (CTE) of La 2 (Zr 0.2 Ce 0.2 Sn 0.2 Hf 0.2 Ti 0.2 ) 2 O 7 ranged from 7.55 × 10 −6 °C −1 to 8.63 × 10 −6 °C −1 for the corresponding range of room temperature to 1000 °C. After 10 thermal cycles at 1050 °C, the La 2 (Zr 0.2 Ce 0.2 Hf 0.2 Sn 0.2 Ti 0.2 ) 2 O 7 top coat spalled in the TBC. Spallation did not occur at the interface between the bond coat and the thermally grown oxide layer, while it is in the top coat near the bond coat. Owing to the low fracture toughness and low CTE, the thermal cycling lifetime of TBCs with the La 2 (Zr 0.2 Ce 0.2 Hf 0.2 Sn 0.2 Ti 0.2 ) 2 O 7 top coat was short.
研究领域:
材料科学
·
陶瓷
·
热障涂层
·
高熵氧化物
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2025
·
IF 4.7
Yuting Qiu,Qingnan Meng,Chi Zhang,Mu Yuan,Xinyue Mao,Sifan Wang,Shiyin Huang
In this study, a wear-resistant epoxy resin (EP) composite coating incorporating surface-modified silicon carbide (SiC) particles was developed. The SiC particles were functionalized through sequential thermal oxidation and silane coupling agent (KH550) modification to yield SiC@SiO 2 -KH550 hybrid fillers. The influence of filler addition and content on the tribological properties was investigated with a pin-on-disk wear tester, whereas the wear morphology was analyzed by scanning electron microscopy (SEM). The results indicate that the neat EP coatings primarily exhibit an adhesive wear mechanism, whereas the composite coatings show a mixed wear mechanism involving adhesion, abrasion, and delamination. The composite coating with 20 wt% SiC@SiO 2 -KH550 filler achieved optimal tribological performance, with reductions in wear rate by 80% and 26% compared to neat EP and unmodified SiC/EP systems, respectively. The enhanced wear resistance is mainly attributed to the modified SiC particles, which promote the formation of transfer films with excellent mechanical properties and a larger area ratio through improved interfacial bonding and dispersion.
研究领域:
材料科学
·
表面工程
·
聚合物复合材料
·
摩擦学
✓ 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）