CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Dapeng Gu,Guanqun Wang,Suwen Chen,Hongtao Luo,Xiaofan Chen,Ziyu Liu
The traditional high-temperature sintering method cannot achieve the combination of ceramics and polymers for the huge sintering temperature difference. The insufficient interfacial bonding strength of the ceramic matrix is the difficulty in the low-temperature preparation of ceramic-polymer composites. To improve the interfacial bonding strength of Si 3 N 4 (Silicon nitride) ceramic matrix composite, an easy-bonding SiO 2 (Silica) shell was introduced onto the surface of the hard-bonding Si 3 N 4 core by Stober method, to obtain Si 3 N 4 @SiO 2 composite. Si 3 N 4 @SiO 2 /PEEK (Polyetheretherketone) composites were prepared by the cold sintering process (500 MPa, 240 °C, and transient liquid phase is NaOH solution). The dry tribological properties of Si 3 N 4 @SiO 2 /PEEK composites with different PEEK percentages were studied by a ball-disc contact form. It is shown that an amorphous SiO 2 shell with a thickness of 25 nm is chemically bonded onto the surface of the Si 3 N 4 core. The presence of the SiO 2 shell improves the interface bonding strength between Si 3 N 4 ceramic particles. The friction coefficients of Si 3 N 4 @SiO 2 /PEEK composites decrease with the increase of PEEK percentage. Compared with Si 3 N 4 @SiO 2 composite, the friction coefficient and wear rate of Si 3 N 4 @SiO 2 /50 vol% PEEK composite decrease by about 40% and 26%, respectively. The main wear forms of Si 3 N 4 @SiO 2 /PEEK composites are abrasive wear and adhesive wear. A mixed lubrication layer, mainly including PEEK, Si 3 N 4 , and SiO 2 , exists simultaneously on the surfaces of Si 3 N 4 @SiO 2 /PEEK composite and the counterpart ball, respectively, playing the role of reducing friction and wear.
研究领域:
材料科学
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机械工程
✓ 已验证
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 14
·4012
·
IF 3.623
Enpei Ma,Zhenghuang Wei,Cheng Lian,Yinping Zhou,Shichang Gan,Bin Xu
This article reports the design and manufacture of colored microcapsules with specific functions and their application in architectural interior wall coating. Utilizing reactive dyes grafted SiO2shell to encapsulate paraffin through interfacial polymerization and chemical grafting methods, this experiment successfully synthesized paraffin@SiO2colored microcapsules. The observations of surface morphology demonstrated that the colored microcapsules had a regular spherical morphology and a well-defined core-shell structure. The analysis of XRD and FT-IR confirmed the presence of amorphous SiO2shell and the grafting reactive dyes, and the paraffin possessed high crystallinity. Compared with pristine paraffin, the thermal conductivity of paraffin@SiO2colored microcapsules was significantly enhanced. The results of DSC revealed that the paraffin@SiO2colored microcapsules performed high encapsulation efficiency and desirable latent heat storage capability. Besides, the examinations of UV-vis and TGA showed that the paraffin@SiO2colored microcapsules exhibited good thermal reliability, thermal stability, and UV protection property. The analysis of infrared imaging indicated that the prepared latex paint exhibited remarkable temperature-regulated property. Compared with normal interior wall coatings, the temperature was reduced by about 2.5 °C. With such incomparable features, the paraffin@SiO2colored microcapsules not only appeared well in their solar thermal energy storage and temperature-regulated property, but also make the colored latex paint coating have superb colored fixing capabilities.
研究领域:
材料科学
·
能源工程
·
建筑涂料
✓ 已验证
DOI
高影响因子
Nanoscale
·
2020
·Vol. 12
·期 31
·16605-16616
·
IF 6.895
Rong Dai,Ziliang Zheng,Chenshuai Lian,Kai Shi,Xu Wu,Xia An,Xianmei Xie
To enhance the catalytic performance of catalysts for the ethanol steam reforming (ESR) reaction, a facile reverse micelle strategy was adopted to prepare a core@shell Ni–Cu@Ca–SiO2 (Ni–Cu@CS) nanoreactor composed of an ultra-small Ni–Cu alloy (∼2.8 nm) encapsulated in Ca-functionalized SiO2 nanoparticles. Benefiting from its core@shell structural features and unique components, the Ni–Cu@CS nanoreactor exhibited superior activity (69.91% H2 selectivity and 99.99% ethanol conversion) and stability compared to reference samples. The regenerated Ni–Cu@CS nanoreactor showed high stability, maintaining 98.14% ethanol conversion and only 1.98 mg gcat−1 h−1 in carbon deposition. The high catalytic performance of Ni–Cu@CS is attributed to not only its encapsulated structure, which effectively prevented the sintering of neighboring Ni–Cu alloy nanoparticles, but also to its Ca-functionalized porous SiO2 shell, suppressing the carbon deposition. Moreover, its porous thin shell facilitated the mass transfer and diffusion of reactants and products. Thus, the Ni–Cu@CS nanoreactor is expected to become a new type of high-efficiency nanoreactor for the ESR reaction.
研究领域:
催化化学
·
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
Nanoscale
·
2012
·Vol. 5
·期 3
·1047-1053
·
IF 5.914
Fuyao Liu,Qi Zhao,Hongpeng You,Zhenxin Wang
Here, a two-step method has been developed for synthesizing carboxy-terminated NaYF4: Yb3+, Er3+@SiO2 core@shell nanoparticles (UCNP@SiO2) with ultrathin shell (1.5 nm). First, the NaYF4: Yb3+, Er3+ upconverting nanoparticles (UCNPs) were prepared using solvothermal technology; then, silica shells (SiO2) were deposited on the nanocrystals to form core–shell structures by the hydrolysis of tetraethylorthosilicate (TEOS). The ultrathin SiO2 shell was obtained by increasing surfactant amount and decreasing TEOS amount in the reaction mixture. Carboxyethylsilanetriol (CTES) was used to generate the carboxy group on the particle surface. The carboxy-terminated UCNP@SiO2 are ideally suited for biolabeling and bioimaging applications because the as-prepared nanoparticles have extreme colloidal and optical stabilities, and the carboxy groups on the particle surface easily react with amino residues of biomolecules. As an example, we reported on the interactions of Ricinus Communis Agglutinin (RCA 120) conjugated UCNP@SiO2 with HeLa cells. The excellent performance of the RCA 120 conjugated UCNP@SiO2 in cellular fluorescence imaging was demonstrated.
研究领域:
材料科学
·
生物医学工程
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Jiabai Cai,Huan Li,Wenjia Huang,Shuting He,Kai Feng,Masaki Takaoka
Biogas slurry, an inevitable outcome of anaerobic digestion (AD), is a treatment burden for urban environmental management. In this study, two kinds of biogas slurry (slurry J and slurry C), collected from the AD plants in Japan and China, were treated using novel TiZrO 4 @Cu and TiZrO 4 @Cu@SiO 2 multilayered hollow spheres containing Cu sub-nanoclusters as the catalyst. The results showed that the chemical oxygen demand (COD) was removed by 63 % for slurry J and 44 % for slurry C after 5 h. The Cu sub-nanoclusters acted as co-catalysts and active centers, facilitating rapid electron transfer to oxygen molecules and forming highly reactive •O 2 − and •OH species (Use slurry J as the based solution). These free radicals cleaved the interconnecting bonds between benzene rings, disintegrated the ring structure, formed intermediate compounds such as n-hexylic acid, and ultimately mineralized organic pollutants in biogas slurry into CO 2 and H 2 O. At the same time, TiZrO 4 @Cu@SiO 2 had excellent stability due to the protection of the SiO 2 shell and reduced threefold Cu leaching than TiZrO 4 @Cu. The COD removal rate was always 60 % in six cycles in the slurry J. The new catalyst ensured the high performance of catalytic air oxidation at low temperatures, which has significant potential as an environmentally friendly and energy-saving method for organic wastewater treatment.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Xinhong Qi,Xiangcun Li,Gaohong He,Yangzhi Zhu,Yurong Diao,Huilan Lu
Noble metal nanocrystals (Au, Pt or AuPt) with controlled compositions and nanostructures were embedded into hollow silica submicrospheres with highly ordered radial mesopores through a one-step sol–gel process. 2,4-Dihydroxybenzoic acid–formaldehyde (RF-COOH) resin submicrospheres were utilized simultaneously as a hard template to create hollow interiors inside the silica submicrospheres and as carriers to transport pregrown metal nanocrystals, including Au nanoparticle (NP), Pt NP, and AuPt nanoalloy, into the submicrospheres. Calcination removes the resin submicrospheres and causes metal nanocrystals embedded into the RF-COOH submicrospheres break into multiple smaller nanoparticles (2–6 nm) that are randomly dispersed in the hollow space of SiO 2 submicrospheres M@SiO 2 (M = Au, Pt or AuPt). The AuPt@SiO 2 submicrospheres showed good catalytic performance for epoxidation of styrene with the conversion and selectivity of 74% and 85%, respectively. The approach reported in this study could potentially be used to simplify the fabrication process of noble metal nanoalloys, which usually entails multiple steps and a previously synthesized hard metal template, and thus guide the design and creation of high-performance catalysts.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 31
·26280-26287
·
IF 3.289
Binbin Li,Heng Liu,Chuanbin Sun,Zeeshan Ahmad,Zhaohui Ren,Xiang Li,Gaorong Han
The investigation of nano-carriers with controllable and trackable drug release kinetics has attracted worldwide attention for new tumor theranostic strategies with catabatic side effects. Herein, a range of monodispersed core–shell structured photoluminescent SrTiO3:Yb3+,Er3+@mSiO2 nanoparticles were designed and synthesized. The surfactant cetyltrimethylammonium bromide (CTAB) was used to vary the microstructure of the mesoporous SiO2 shell. The specific surface area and pore volume increase proportionally with the content of CTAB. Consequently, the doxorubicin (DOX) loading capacity increases, and the drug release kinetics possesses a sustained behaviour. More importantly, the DOX release kinetics was found to correspond well to the evolution of the up-conversion luminescence (UCL) phenomenon. More rapid drug release induces more rapid photoluminescence enhancement, and vice versa. This study has therefore been anticipated to suggest another promising multifunctional drug delivery platform for advanced chemotherapies.
研究领域:
纳米医学
·
药物递送系统
·
生物材料
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Guangchao Li,Youbin Zheng,Hao Guo,Ze Li,Guohao Zhu,Liang Dong,Xin Liu,Jianbing Zang
In this paper, we present a method to enhance the stability of Fe–N–C electrocatalysts, known for their significant oxygen reduction reaction (ORR) activity and positioned as promising alternatives to commercial noble metal-based catalysts. Despite the favorable ORR activity, Fe–N–C suffers from inadequate stability in acidic media, primarily attributed the loss of active FeN 4 sites resulted from Fe-demetalation. However, recent investigation reveals that pyridine N exhibits remarkable stability in retaining Fe atoms. To address this, we achieved a high proportion of pyridine N doping in carbon nanofibers through a process involving nano-SiO 2 shell coating and electrospinning. The nano-SiO 2 shell coating method demonstrates efficacy and versatility in transforming pyrrole-type FeN 4 into pyridine-type FeN 4 , irrespective of the origin material being trivalent or divalent Fe, whether organic or inorganic.
研究领域:
电化学
·
材料科学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Lingwei Li,Huan Wang,Jixiang Fang
Magnetic fluorescent nanomaterials have broad application prospects as taggants in fields such as anticounterfeiting identification, suspicious object tracking, and potential fingerprint recognition in forensic medicine. It is a common method to synthesize magnetic fluorescent composite nanoparticles by preparing a shell on the surface of magnetic particles to load fluorescent materials. In this work, a magnetic fluorescence nanohybrid was synthesized by in situ encapsulation of carbon quantum dots (CQDs) during the preparation of a SiO2 shell on the surface of Fe3O4 nanoparticles. The traditional Stöber method was employed to synthesize the SiO2 shell. Meanwhile, CQDs were introduced into the hydrolysis process of tetraethyl orthosilicate. To address the issue of charge repulsion between the negatively charged hydrolysis intermediate of tetraethyl orthosilicate and the negatively charged CQDs, poly(diallyldimethylammonium chloride) with positive charge was introduced in the synthesis process. The repulsive charges in the reaction system were balanced by poly(diallyldimethylammonium chloride), allowing for the successful encapsulation of CQDs in the SiO2 shell. The structure, morphology, and magnetic and fluorescence properties of the prepared Fe3O4@SiO2–CQDs were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, a vibrating sample magnetometer, and a fluorescence spectrophotometer. The Fe3O4@SiO2–CQDs exhibited excellent magnetic and fluorescence properties, making them suitable for fluorescence labeling on various substrates and showing great potential in labeling, tracing, and fluorescence sensors.
研究领域:
材料科学
·
纳米技术
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2022
·
IF 3.754
Shuo Song,Wenzhi Wang,Bingqiang Cao
Halide perovskite quantum dots (PQDs) have been considered to be potential emitting materials for illumination and display applications. Unfortunately, the poor stability (air, water, and thermal) can greatly limit their practical applications. Herein, the mono-dispersed pure CsPbBr 3 PQDs with cubic morphologies are prepared by using a modified hot-injection method, as a control group. Based on this, a new surface activation strategy for preparing single CsPbBr 3 @SiO 2 core-shell PQDs with their initial cubic morphology and optical properties has been developed, using the CsPbBr 3 PQDs as a precursor and choosing the APTES as the surface ligand which can form a Si–O–Si covalent bond with the subsequently added silane to help complete single CsPbBr 3 @SiO 2 PQDs. The average thickness of the coated shell is about 2.3 nm and basically maintains the initial morphology and optical properties of PQDs. The PL intensity of CsPbBr 3 @SiO 2 PQDs dispersed in a mixed solution of toluene and water can retained 35% of the initial value even after 13 h, which are much higher than the pure CsPbBr 3 PQDs (9%). The photo-stability tests (air, water, and thermal stability) indicate that the CsPbBr 3 @SiO 2 PQDs is markedly more stable than that of the CsPbBr 3 PQDs owing to the complete encapsulation of the SiO 2 shell, indicating that the host packaging is an effective way to improve the stability. This work provides a simple and reliable synthesis way to synthesize the single core-shell particles, which can be suitable for other perovskite systems.
研究领域:
材料科学
·
纳米技术
·
光电技术
·
化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Jinze Lyu,Junxian Gao,Min Zhang,Yanhong Wang,Dandan Hu,Juan Yi,Junbo Zhong,Ji Li,Shuo Wang
The distribution of bulk and surface defects significantly affects the separation and injection of photogenerated charge carriers. In this study, we provide a strategy of SiO 2 -shell-enhanced F modification to optimize the distribution of bulk and surface defects. The effects of SiO 2 coating and F modification on the physical structure, the separation behavior of photogenerated charge carriers, and the photocatalytic activity of P25 were studied by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, surface photovoltage spectroscopy, and toluene degradation experiments. Results showed that the removal rate of toluene over SiO 2 -F-modified P25 was significantly higher than those over P25 and F modified P25. The SiO 2 -shell-enhanced F modification simultaneously increased the content of surface Ti 3+ and reduced the bulk defects, thereby enhancing the separation of charge carriers. Furthermore, F doped at surface exerted a strong catalytic effect on the removal of toluene, whereas F doped in lattice caused the recombination of photogenerated charge carriers. The SiO 2 coating and calcination treatment significantly increased the amount of F ions doped at TiO 2 surface and inhibited F doping in lattice.
研究领域:
环境科学
·
材料科学
·
化学
✓ 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）