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Assembly of functional carboxymethyl cellulose/polyethylene oxide/anatase TiO_(2) nanocomposites and tuning the dielectric relaxation, optical, and photoluminescence performances
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作者 Asmaa M.Ismail Abeer A.Reffaee Fawzy G.El Desouky 《Journal of Semiconductors》 EI CAS CSCD 2024年第7期26-38,共13页
Nanocomposite films consisting of carboxymethyl cellulose,polyethylene oxide(CMC/PEO),and anatase titanium diox-ide(TO)were produced by the use of sol-gel and solution casting techniques.TiO2 nanocrystals were effecti... Nanocomposite films consisting of carboxymethyl cellulose,polyethylene oxide(CMC/PEO),and anatase titanium diox-ide(TO)were produced by the use of sol-gel and solution casting techniques.TiO2 nanocrystals were effectively incorporated into CMC/PEO polymers,as shown by X-ray diffraction(XRD)and attenuated total reflectance fourier transform infrared(ATR-FTIR)analysis.The roughness growth is at high levels of TO nanocrystals(TO NCs),which means increasing active sites and defects in CMC/PEO.In differential scanning calorimetry(DSC)thermograms,the change in glass transition temperature(Tg)val-ues verifies that the polymer blend interacts with TO NCs.The increment proportions of TO NCs have a notable impact on the dielectric performances of the nanocomposites,as observed.The electrical properties of the CMC/PEO/TO nanocomposite undergo significant changes.The nanocomposite films exhibit a red alteration in the absorption edge as the concentration of TO NCs increases in the polymer blend.The decline in the energy gap is readily apparent as the weight percentage of TO NCs increases.The photoluminescence(PL)emission spectra indicate that the sites of the luminescence peak maximums show slight variation;peaks get wider,while their intensities decrease dramatically as the concentration of TO increases.These nanocomposite materials show potential for multifunctional applications including optoelectronics,antireflection coatings,pho-tocatalysis,light emitting diodes,and solid polymer electrolytes. 展开更多
关键词 anatase TiO_(2) CMC/PEO nanocomposites optical PHOTOLUMINESCENT electrical optoelectronics
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Photocatalytic ozonation-based degradation of phenol by ZnO—TiO_(2)nanocomposites in spinning disk reactor
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作者 Xueqing Ren Jiahao Niu +5 位作者 Yan Li Lei Li Chao Zhang Qiang Guo Qiaoling Zhang Weizhou Jiao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第8期74-84,共11页
Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by adva... Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by advanced oxidation processes(AOPs).In this study,ZnO—TiO_(2)nanocomposites were prepared by solgel method,and coated on the disk of SDR by impregnation-pull-drying-calcination method.The performance of catalyst was characterized by X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,photoluminescence and ultraviolet—visible diffuse reflectance spectroscopy.Photocatalytic ozonation in SDR was used to remove phenol,and various factors on degradation effect were studied in detail.The results showed that the rate of degradation and mineralization reached 100%and 83.4%under UV light irradiation after 50 min,compared with photocatalysis and ozonation,the removal rate increased by 69.3%and 34.7%,and mineralization rate increased by 56.7%and 62.9%,which indicated that the coupling of photocatalysis and ozonation had a synergistic effect.The radical capture experiments demonstrated that the active species such as photogenerated holes(h^(+)),hydroxyl radicals(·OH),superoxide radical(·O_(2)-)were responsible for phenol degradation,and·OH played a leading role in the degradation process,while h+and·O_(2)^(-)played a non-leading role. 展开更多
关键词 Spinning disk reactor Photocatalytic ozonation ZnO-TiO_(2)nanocomposites Advanced oxidation processes
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Deflagration to detonation transition in weakly confined conditions for a type of potentially novel green primary explosive:Al/Fe_(2)O_(3)/RDX hybrid nanocomposites 被引量:2
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作者 Qing-ping Luo Xin-ping Long +2 位作者 Fu-de Nie Gui-xiang Liu Chao Wu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第4期28-36,共9页
The properties of the combustion and deflagration to detonation transition(DDT)of Al/Fe_(2)O_(3)/RDX hybrid nanocomposites,a type of potentially novel lead-free primary explosives,were tested in weakly confined condit... The properties of the combustion and deflagration to detonation transition(DDT)of Al/Fe_(2)O_(3)/RDX hybrid nanocomposites,a type of potentially novel lead-free primary explosives,were tested in weakly confined conditions,and the interaction of Al/Fe_(2)O_(3)nanothermite and RDX in the DDT process was studied in detail.Results show that the amount of the Al/Fe_(2)O_(3)nanothermite has a great effect on the DDT properties of Al/Fe_(2)O_(3)/RDX nanocomposites.The addition of Al/Fe_(2)O_(3)nanothermite to RDX apparently improves the firing properties of RDX.A small amount of Al/Fe_(2)O_(3)nanothermite greatly increases the initial combustion velocity of Al/Fe_(2)O_(3)/RDX nanocomposites,accelerating their DDT process.When the contents of Al/Fe_(2)O_(3)nanothermite are less than 20 wt%,the DDT mechanisms of Al/Fe_(2)O_(3)/RDX nanocomposites follow the distinct abrupt mode,and are consistent with that of RDX,though their DDT processes are different.The RDX added into the Al/Fe_(2)O_(3)nanothermite increases the latter's peak combustion velocity and makes it generate the DDT when the RDX content is at least 10 wt%.RDX plays a key role in the shock compressive combustion,the formation and the properties of the DDT in the flame propagation of nanocomposites.Compared with RDX,the fast DDT of Al/Fe_(2)O_(3)/RDX nanocomposites could be obtained by adjusting the chemical constituents of nanocomposites. 展开更多
关键词 Green primary explosives Al/Fe_(2)O_(3)/RDX nanocomposites Deflagration to detonation transition Mechanism
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MoS_(2)/ZnO异质结纳米材料降解亚甲基蓝的光催化性能研究 被引量:1
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作者 王进美 蒋守杰 +2 位作者 王春霞 王丽丽 高大伟 《西安工程大学学报》 CAS 2024年第1期24-30,共7页
为了提高ZnO的光转换效率,选用带隙较低的MoS_(2)形成异质结提高ZnO的光催化性能。通过水热法制备ZnO纳米棒,并进一步制备MoS_(2)/ZnO异质结构的纳米复合材料。通过扫描电镜(SEM)、X射线粉末衍射仪(XRD)、固体紫外可见漫反射测试仪(UV-V... 为了提高ZnO的光转换效率,选用带隙较低的MoS_(2)形成异质结提高ZnO的光催化性能。通过水热法制备ZnO纳米棒,并进一步制备MoS_(2)/ZnO异质结构的纳米复合材料。通过扫描电镜(SEM)、X射线粉末衍射仪(XRD)、固体紫外可见漫反射测试仪(UV-Vis)和紫外可见分光光度计(UV-245)等分析方法对样品的形貌、结构及光学性能等进行表征。结果表明,MoS_(2)/ZnO异质结复合材料呈棒状结构,并由于内建电场存在可有效增强光生载流子的分离效率,进而提高了可见光区的吸收,提高了光催化性能。在模拟太阳光(包含紫外波段)下,60 min时MoS_(2)-15/ZnO纳米复合材料对亚甲基蓝的降解率可达99%,比纯ZnO的降解率提高了10%。 展开更多
关键词 MoS_(2)/ZnO 光催化 异质结 亚甲基蓝 纳米复合材料
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Preparation and shape memory properties of TiO_2/PLCL biodegradable polymer nanocomposites 被引量:3
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作者 鲁玺丽 吕秀乾 +2 位作者 王建永 孙志洁 佟运祥 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期120-127,共8页
The preparation of TiO2/poly(L-lactide-co-ε-caprolactone)(PLCL) nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone(ε-CL)... The preparation of TiO2/poly(L-lactide-co-ε-caprolactone)(PLCL) nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone(ε-CL).The resulting poly(ε-caprolactone)-grafted TiO2(g-TiO2) was characterized by Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA) and transmission electron microscopy(TEM).The g-TiO2can be uniformly dispersed in chloroform and the g-TiO2/PLCL nanocomposites were successfully fabricated through solvent-casting method.The effects of the content of g-TiO2nanoparticles on tensile properties and shape memory properties were investigated.A significant improvement in the tensile properties of the 5% g-TiO2/PLCL mass fraction nanocomposite is obtained:an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer.The g-TiO2/PLCL nanocomposites with a certain amount of g-TiO2content have better shape memory properties than pure PLCL polymer.The g-TiO2nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties. 展开更多
关键词 poly(L-lactide-co-ε-caprolactone) nanocomposites TiO2nanoparticles surface grafting shape memory properties mechanical properties
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Influence of tool rotational speed on mechanical and corrosion behaviour of friction stir processed AZ31/Al_(2)O_(3)nanocomposite 被引量:1
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作者 Ashish Kumar V.P.Singh +5 位作者 Akhileshwar Nirala R.C.Singh Rajiv Chaudhary Abdel-Hamid I.Mourad B.K.Sahoo Deepak Kumar 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第7期2585-2599,共15页
Nano-sized reinforcements improved the mechanical characteristics efficiently by promoting more implicit particle hardening mechanisms compared to micron-sized reinforcements.Nano-sized particles lessen the critical p... Nano-sized reinforcements improved the mechanical characteristics efficiently by promoting more implicit particle hardening mechanisms compared to micron-sized reinforcements.Nano-sized particles lessen the critical particle solidification velocity for swamp and thus offers better dispersal.In the present investigation,the friction stir processing(FSP)is utilized to produce AZ31/Al_(2)O_(3)nanocomposites at various tool rotation speeds(i.e.,900,1200,and 1500 rpm)with an optimized 1.5%volume alumina(Al_(2)O_(3))reinforcement ratio.The mechanical and corrosion behavior of AZ31/Al_(2)O_(3)-developed nanocomposites was investigated and compared with that of the AZ31 base alloy.The AZ31 alloy experienced a comprehensive dynamic recrystallization during FSP,causing substantial grain refinement.Grain-size strengthening is the primary factor contributed to the enhancement in the strength of the fabricated nanocomposite.Tensile strength and yield strength values were lower than those for the base metal matrix,although an upward trend in both values has been observed with an increase in tool rotation speed.An 19.72%increase in hardness along with superior corrosion resistance was achieved compared to the base alloy at a tool rotational speed of 1500 rpm.The corrosion currents(Jcorr)of all samples dropped with increase in the rotational speed,in contrast to the corrosion potentials(Ecorr),which increased.The values of Jcorr of AZ31/Al_(2)O_(3)were 42.3%,56.8%,and 65.5%lower than those of AZ31 alloy at the chosen rotating speeds of 900,1200,and 1500 rpm,respectively.The corrosion behavior of friction stir processed nanocomposites have been addressed in this manuscript which has not been given sufficient attention in the existing literature.Further,this work offers an effective choice for the quality assurance of the FSP process of AZ31/Al_(2)O_(3)nanocomposites.The obtained results are relevant to the development of lightweight automobile and aerospace structures and components. 展开更多
关键词 Friction stir processing AZ31 alloy Al_(2)O_(3) nanocompositE Mechanical properties Corrosion resistance
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Surface functionalized N-C-TiO_(2)/C nanocomposites derived from metal-organic framework in water vapour for enhanced photocatalytic H generation 被引量:6
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作者 Mian Zahid Hussain Zhuxian Yang +7 位作者 Bart van der Linden Zheng Huang Quanli Jia Erik Cerrato Roland A.Fischer Freek Kapteijn Yanqiu Zhu Yongde Xia 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第6期485-495,I0012,共12页
Surface-functionalized nitrogen/carbon co-doped polymorphic TiO_(2) phase junction nanoparticles uniformly distributed in porous carbon matrix were synthesized by a simple one-step pyrolysis of titanium based metal-or... Surface-functionalized nitrogen/carbon co-doped polymorphic TiO_(2) phase junction nanoparticles uniformly distributed in porous carbon matrix were synthesized by a simple one-step pyrolysis of titanium based metal-organic framework(MOF),NH_(2)-MIL^(-1)25(Ti) at 700℃ under water vapour atmosphere.Introducing water vapour during the pyrolysis of NH_(2)-MIL^(-1)25(Ti) not only functionalizes the derived porous carbon matrix with carboxyl groups but also forms additional oxygen-rich N like interstitial/intraband states lying above the valence band of TiO2 along with the self-doped carbo n,which further narrows the energy band gaps of polymorphic TiO2 nanoparticles that enhance photocatalytic charge transfer efficiency.Without co-catalyst,sample N-C-TiO2/CArW demonstrates H_(2) evolution activity of 426 μmol gcat-1h^(-1),which remarkably outperforms commercial TiO_(2)(P-25) and N-C-TiO_(2)/CAr with a 5-fold and 3-fold H_(2) generation,respectively.This study clearly shows that water vapour atmosphere during the pyrolysis increases the hydrophilicity of the Ti-MOF derived composites by functionalizing porous carbon matrix with carboxylic groups,as well as enhancing the electrical conductivity and charge transfer efficiency due to the formation of additional localized oxygen-rich N like interstitial/intraband states.This work also demonstrates that by optimizing the anatase-rutile phase composition of the TiO2 polymorphs,tuning the energy band gaps by N/C co-doping and functionalizing the porous carbon matrix in the N-C-TiO2/C nanocomposites,the photocatalytic H_(2) generation activity can be further enhanced. 展开更多
关键词 Metal-organic framework TiO_(2) Porous carbon nanocompositE PHOTOCATALYSIS Hydrogen generation
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Study on Preparation and Properties of La_2O_3/MC Nylon Nanocomposites 被引量:9
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作者 林轩 张平民 +1 位作者 尹周谰 陈启元 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第6期680-684,共5页
A series of La2O3/MC nylon nanocomposites were prepared via in situ polymerization. The effects of content of nano-La2O3 on the mechanical properties of nanocomposites were studied. Dispersion of nano-La2O3 in MC nylo... A series of La2O3/MC nylon nanocomposites were prepared via in situ polymerization. The effects of content of nano-La2O3 on the mechanical properties of nanocomposites were studied. Dispersion of nano-La2O3 in MC nylon matrix was observed with SEM. The crystal structure of nanocomposites was characterized by means of XRD. SEM analysis shows that La2O3 nanoparticles are uniformly dispersed in MC nylon matrix and little clustering exists when the content of nano- La2O3 is lower than 1%, however, when the content of nano-La2O3 is more than 1%, it begins to cluster. XRD analysis indicats that nano-La2O3 does not change the crystal structure of MC nylon. Mechanical properties tests show that the tensile strength, elongation at break, impact strength, flexural strength, and flexural modulus of nanocomposites first increase then decrease as the content of nano-La2O3 is increased. When the content of nano-La2O3 is 0.5%, the tensile strength and elongation at break of nanocomposites reach maximum, which are 17.9% and 52.1% higher respectively than those of MC nylon. When the content of nano-La2O3 is 1.0%, the impact strength, flexural strength and flexural modulus of nanocomposites reach maximum, which are 36.6 %, 12.7 % and 16.3 % higher respectively than those of MC nylon. 展开更多
关键词 MC nylon nano-La2O3 nanocomposites in situ polymerization mechanical properties rare earths
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ZIF⁃67衍生Co@C/MoS_(2)纳米复合材料的制备及微波吸收性能
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作者 李敏 孟献丰 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第10期1932-1942,共11页
通过碳化技术和水热反应相结合成功制备了Co@C/MoS_(2)复合吸波材料。结果表明,ZIF⁃67的碳化温度和Co@C/MoS_(2)的微观结构对Co@C/MoS_(2)复合材料的吸波性能具有重要影响。Co@C/MoS_(2)的褶皱结构增强了入射波的反射与散射,进而优化了... 通过碳化技术和水热反应相结合成功制备了Co@C/MoS_(2)复合吸波材料。结果表明,ZIF⁃67的碳化温度和Co@C/MoS_(2)的微观结构对Co@C/MoS_(2)复合材料的吸波性能具有重要影响。Co@C/MoS_(2)的褶皱结构增强了入射波的反射与散射,进而优化了阻抗匹配,提高了材料的电磁波(EMW)吸收性能。当碳化温度为800℃,样品匹配厚度为1.7 mm时,Co@C/MoS_(2)复合材料展现出最佳的吸波性能,最小反射损耗(RL_(min))和有效吸收带宽(EAB)分别达到-101.84 dB和7.4 GHz。 展开更多
关键词 纳米复合材料 ZIF⁃67 Co@C/MoS_(2) 电磁波吸收
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Recent progress on gas sensors based on graphene-like 2D/2D nanocomposites 被引量:3
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作者 Songyang Yuan Shaolin Zhang 《Journal of Semiconductors》 EI CAS CSCD 2019年第11期85-98,共14页
Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,n... Two-dimensional(2D)nanomaterials have demonstrated great potential in the field of flexible gas sensing due to their inherent high specific surface areas,unique electronic properties and flexibility property.However,numerous challenges including sensitivity,selectivity,response time,recovery time,and stability have to be addressed before their practical application in gas detection field.Development of graphene-like 2D/2D nanocomposites as an efficient strategy to achieve high-performance 2D gas sensor has been reported recently.This review aims to discuss the latest advancements in the 2D/2D nanocomposites for gas sensors.We first elaborate the gas-sensing mechanisms and the collective benefits of 2D/2D hybridization as sensor materials.Then,we systematically present the current gas-sensing applications based on different categories of 2D/2D nanocomposites.Finally,we conclude the future prospect of 2D/2D nanocomposites in gas sensing applications. 展开更多
关键词 gas SENSOR 2D NANOMATERIALS 2D/2D nanocompositE HETEROJUNCTION flexible SENSOR
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BaF_(2)纳米复合闪烁体的闪烁特性研究
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作者 郭泉 李阳 +3 位作者 陈俊峰 李翔 张美 盛亮 《现代应用物理》 2024年第5期32-37,共6页
为研究基于BaF_(2)无机纳米颗粒复合闪烁体的闪烁特性,将粒径约为20 nm的BaF_(2)无机纳米颗粒与塑料闪烁体结合,制作了不同质量分数的BaF_(2)纳米复合闪烁体。通过闪烁光谱测量系统、时间关联单光子计数系统、基于钴源的γ射线辐照系统... 为研究基于BaF_(2)无机纳米颗粒复合闪烁体的闪烁特性,将粒径约为20 nm的BaF_(2)无机纳米颗粒与塑料闪烁体结合,制作了不同质量分数的BaF_(2)纳米复合闪烁体。通过闪烁光谱测量系统、时间关联单光子计数系统、基于钴源的γ射线辐照系统,实验测量了BaF_(2)纳米复合闪烁体在低能X射线和γ射线(1.25 MeV)辐射下的闪烁效率、闪烁光谱和发光衰减时间。实验结果表明,在低能X射线和γ射线激发下,基于BaF_(2)纳米颗粒的复合闪烁体可以将发光效率分别提升83.1倍和16.4倍;同时由于BaF_(2)无机纳米颗粒的尺寸效应有效地压制了其慢衰减时间的发光成分(来源于自陷态激子效应),从而使得该BaF_(2)纳米复合闪烁体具有与塑料闪烁体相近的闪烁光谱,快衰减时间约为2 ns。 展开更多
关键词 纳米复合闪烁体 BaF_(2) X射线 Γ射线
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Preparation and Photocatalytic Activity of BiOBr/TiO_2 Heterojunction Nanocomposites 被引量:4
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作者 谭欣 李香利 +1 位作者 于涛 赵阳 《Transactions of Tianjin University》 EI CAS 2016年第3期211-217,共7页
An efficient visible-light-responsive BiOBr/TiO2 heterojunction nanocomposite was fabricated successfully using in-situ depositing technique at room temperature by introducing BiOBr onto the surface of TiO2 nano- belt... An efficient visible-light-responsive BiOBr/TiO2 heterojunction nanocomposite was fabricated successfully using in-situ depositing technique at room temperature by introducing BiOBr onto the surface of TiO2 nano- belts pre-prepared by hydrothermal reaction and etched with H2SO4. The obtained particles were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS and PL techniques. BiOBr/TiO2 heterojunction nanocomposites with different mass ratios of m (BiOBr)/m (TiO2) were discussed in order to get the best photocatalytie activity, and BiOBr/TiO2-1.0 was proved to be the optimal mass ratio. BiOBr/TiO2-1.0 exhibited excellent photocatalytic activity in the degradation of RhB compared with TiO2 nanobelts, pure BiOBr and the mechanical mixture of TiO2 nanobelts and BiOBr. At last, a possible mechanism ofphotocatalytic enhancement was proposed. 展开更多
关键词 PHOTOCATALYSIS BiOBr TiO2 nanobelt HETEROJUNCTION nanocompositE visible light
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Photoluminescence behavior and visible light photocatalytic activity of ZnO,ZnO/ZnS and ZnO/ZnS/α-Fe_2O_3 nanocomposites 被引量:5
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作者 Gaurav HITKARI Sandhya SINGH Gajanan PANDEY 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第7期1387-1397,共11页
In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange(MeO), ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic... In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange(MeO), ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic route in the aqueous medium. Phase, crystallinity, surface structure and surface behavior of the synthesized materials were determined by X-ray diffraction(XRD) and Brunauer-Emmett-Teller analysis(BET) techniques. XRD study established formation of good crystalline ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanomaterials. By using intensity of constituent peaks in the XRD pattern, the compositions of nanocomposites were determined. From the BET analysis, the prepared materials show mesoporous behavior, type Ⅳ curves along with H4 hysteresis. The ZnO/ZnS/α-Fe2O3 composite shows the largest surface area among three materials. From the UV-visible spectra, the band gap energy of the materials was determined. Photoluminescence spectra(PL) were used to determine the emission behavior and surface defects in the materials. In PL spectra, the intensity of UV peak of ZnO/ZnS is lowered than that of ZnO while in case of ZnO/ZnS/α-Fe2O3, the intensity further decreased. The visible emission spectra of ZnO/ZnS increased compared with ZnO while in ZnO/ZnS/α-Fe2O3 it is further increased compared with ZnO/ZnS. The as-synthesized materials were used as photocatalysts for the degradation of dye MeO. The photo-degradation data revealed that the ZnO/ZnS/α-Fe2O3 is the best photocatalyst among three specimens for the degradation of dye MeO. The decrease of intensity of UV emission peak and the increase of intensity of visible emission cause the decrease of recombination of electrons and holes which are ultimately responsible for the highest photocatalytic activity of ZnO/ZnS/α-Fe2O3. 展开更多
关键词 nanocomposite ZNO ZNS Α-FE2O3 CALCINATION optical properties photocatalytic activity
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Fabrication of AA2024−TiO2 nanocomposites through stir casting process 被引量:6
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作者 Mehrdad SHAYAN Beitallah EGHBALI Behzad NIROUMAND 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第11期2891-2903,共13页
Given the nonuse of TiO2 nanoparticles as the reinforcement of AA2024 alloy in fabricating composites by ex-situ casting methods,it was decided to process the AA2024−xTiO2(np)(x=0,0.5 and 1 vol.%)nanocomposites by emp... Given the nonuse of TiO2 nanoparticles as the reinforcement of AA2024 alloy in fabricating composites by ex-situ casting methods,it was decided to process the AA2024−xTiO2(np)(x=0,0.5 and 1 vol.%)nanocomposites by employing the stir casting method.The structural properties of the produced samples were then investigated by optical microscopy and scanning electron microscopy;their mechanical properties were also addressed by hardness and tensile tests.The results showed that adding 1 vol.%TiO2 nanoparticles reduced the grain size and dendrite arm spacing by about 66%and 31%,respectively.Also,hardness,ultimate tensile strength,yield strength,and elongation of AA2024−1vol.%TiO2(np)composite were increased by about 25%,28%,4%and 163%,respectively,as compared to those of the monolithic component.The agglomerations of nanoparticles in the structure of nanocomposites were found to be a factor weakening the strength against the strengthening mechanisms.Some agglomerations of nanoparticles in the matrix were detected on the fractured surfaces of the tension test specimens. 展开更多
关键词 AA2024−TiO2 nanocomposites mechanical properties MICROSTRUCTURE fracture surface stir casting process
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Morphology and Mechanical Properties of PS/Al_2O_3 Nanocomposites Based on Selective Laser Sintering 被引量:6
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作者 Zhifeng XU Jian ZHANG +2 位作者 Haizhong ZHENG Changchun CAI Yinhui HUANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第6期866-870,共5页
Selective laser sintering (SLS) is a new process to prepare the polystyrene (PS)/Al2O3 nanocomposites. In this paper, with different laser power and other processing parameters unchanged, the morphology, density a... Selective laser sintering (SLS) is a new process to prepare the polystyrene (PS)/Al2O3 nanocomposites. In this paper, with different laser power and other processing parameters unchanged, the morphology, density and mechanical properties of the sintered specimens were investigated. It was found that nano-sized inorganic particles are uniformly located in the PS matrix and the maximum density of the sintered specimens with pure PS powder reaches 1.07 g/cm^3, higher than 1.04 g/cm^3 that of the sintered specimens with mixture powder. Due to strengthening and toughness of the nano-sized Al2O3 inorganic particles, the maximum notched impact strength and tensile strength of the sintered part mixed with nano-sized inorganic particles are improved greatly from 7.5 to 12.1 kJ/m^2 and from 6.5 to 31.2 MPa, respectively, under the same sintering condition. 展开更多
关键词 Selective laser sintering (SLS) nanocomposites Polystyrene (PS) Nano-Al2O3 Laser power Mechanical properties MORPHOLOGY
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A NOVEL RESISTIVE HUMIDITY SENSOR BASED ON SODIUM POLYSTYRENESULFONATE/TiO_2 NANOCOMPOSITES 被引量:2
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作者 Yang Li Mu-jie Yang Yong She Department of Polymer Science and Engineering Zhejiang University, Hangzhou 310027 China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2002年第3期237-241,共5页
A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2 nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis... A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2 nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis (< 4% RH) and quicker response (absorption: less than 2 s; desorption: less than 20 s) in comparison with sensor composed of NaPSS. The effect of concentration of NaPSS and TiO2 on humidity response of sensors was discussed. 展开更多
关键词 humidity sensor nanocomposites TIO2 sodium polystyrenesulfonate
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Structural characteristics and dielectric properties of glass-ceramic nanocomposites of(Pb,Sr)Nb_2O_6-NaNbO_3-SiO_2 被引量:3
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作者 王磊 张庆猛 杜军 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第8期1434-1438,共5页
The structure and dielectric properties of (Pb,Sr)Nb2O6-NaNbO3-SiO2 glass-ceramics with different Pb and Sr contents were investigated. The XRD pattern of glass-ceramics without Sr substitution is different from tha... The structure and dielectric properties of (Pb,Sr)Nb2O6-NaNbO3-SiO2 glass-ceramics with different Pb and Sr contents were investigated. The XRD pattern of glass-ceramics without Sr substitution is different from that with Sr substitution, which indicates the existence of orthorhombic phase in the latter ones. TEM bright field observation shows nanosized microstructures, while for samples with Sr, typical eutectic microstrncture with separated crystallized bands is found in the glass matrix. Dielectric properties measurement of the samples indicates an obvious improvement of dielectric constant, dielectric loss, DC field and temperature dependence of dielectric constant when the molar ratio of Sr to Pb is 4:6. 展开更多
关键词 dielectric properties nanocompositE (Pb Sr)Nb2O6 NaNbO3 GLASS-CERAMICS
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Enhanced photocatalytic activity of methylene blue using heterojunction Ag@TiO_(2)nanocomposite:Mechanistic and optimization study
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作者 Saptarshi Ghosh Kamalesh Sen +2 位作者 Priyanka Debnath Arghadip Mondal Naba Kumar Mondal 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第12期49-63,共15页
The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were ... The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were pH,UV-irradiation time,temperature,catalytic dosage,and concentration of MB.The results showed that 0.2×10^(3) g·ml^(-1))of the catalytic dose caused the Ag@TiO_(2)adsorption to degrade by 96.67%with darks and UV exposure.Using the Langmuir-Hinshelwood model to determine the kinetic,the Ag@TiO_(2)displays a greater kinetic rate than TiO_(2)and silver nanoparticle(AgNPs).The photocatalytic degradation of MB,which is an endothermic reaction involving all catalysts,is shown by the thermodynamic parameter to have the positive value of enthalpy(ΔH°).The enthalpies observed were Ag@TiO_(2)(126.80 kJ·mol^(-1))<AgNPs(354.47 kJ·mol^(-1))<TiO_(2)(430.04 kJ·mol^(-1)).Ascorbic acid(·OH scavenger),2-propanol(·O_(2)scavenger),and ammonium oxalate(AO)(hole h+scavenger)were employed to conduct the scavenger effects.The Ag@TiO_(2)demonstrated a reduction in MB degradation when combined with 2-propanol,and this clearly demonstrated that,in contrast to hydroxyl radicals(·OH)and holeh scavengers,superoxide radical anion(O_(2)scavenger)plays a significant role in MB degradation.Utilizing density functional theory(DFT)to elucidate the mechanism and B3LYP/6-311+G(d,p)level optimization,the degradation-adsorption process was explained.When the N-N,C-N or C-C bonds were severed,the Fukui faction was demonstrated for nucleophilic,electrophilic,and radical attack. 展开更多
关键词 Heterojunction Ag@TiO_(2)nanocomposite Methylene blue dye Langmuir-Hinshelwood model SCAVENGER Density functional theoty
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Tunable localized surface plasmon resonances in MoO_(3-x)-TiO_(2) nanocomposites with enhanced catalytic activity for CO_(2) photoreduction under visible light 被引量:4
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作者 Shunji Xie Haikun Zhang +4 位作者 Guodong Liu Xuejiao Wu Jinchi Lin Qinghong Zhang Ye Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1125-1131,共7页
The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported ... The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported to be capable of catalyzing the photocatalytic reduction of CO2 under visible light.The utilization of the localized surface plasmon resonance(LSPR)phenomenon is an attractive strategy for developing visible-light photocatalysts.Herein,we have succeeded in synthesizing plasmonic MoO3?x-TiO2 nanocomposites with tunable LSPR by a simple solvothermal method.The well-structured nanocomposite containing two-dimensional(2D)molybdenum oxide(MoO3?x)nanosheets and one-dimensional(1D)titanium oxide nanotubes(TiO2-NT)showed LSPR absorption band in the visible-light region,and the incorporation of TiO2-NT significantly enhanced the LSPR absorption band.The MoO3?x-TiO2-NT nanocomposite is promising for application in the photocatalytic reduction of CO2 with H2O under visible light irradiation. 展开更多
关键词 PHOTOCATALYSIS Carbon dioxide Visible light Localized surface plasmon resonance MoO_(3-x)-TiO_(2) nanocomposite
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Synthesis of TiO_2/g-C_3N_4 nanocomposites with phosphate–oxygen functional bridges for improved photocatalytic activity 被引量:7
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作者 Chong Liu Fazal Raziq +3 位作者 Zhijun Li Yang Qu Amir Zada Liqiang Jing 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第6期1072-1078,共7页
One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface ... One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface contact in the fabricated nanocomposite greatly influences the charge transfer and separation so as to determine the final photocatalytic activities.However,the role of interface contact is often neglected,and is rarely reported to date.Hence,it is possible to further enhance the photocatalytic activity of g‐C3N4‐based nanocomposite by improving the interfacial connection.Herein,phosphate-oxygen(P-O)bridged TiO2/g‐C3N4nanocomposites were successfully synthesized using a simple wet chemical method,and the effects of the P-O functional bridges on the photogenerated charge separation and photocatalytic activity for pollutant degradation and CO2reduction were investigated.The photocatalytic activity of g‐C3N4was greatly improved upon coupling with an appropriate amount of nanocrystalline TiO2,especially with P-O bridged TiO2.Atmosphere‐controlled steady‐state surface photovoltage spectroscopy and photoluminescence spectroscopy analyses revealed clearly the enhancement of photogenerated charge separation of g‐C3N4upon coupling with the P-O bridged TiO2,resulting from the built P-O bridges between TiO2and g‐C3N4so as to promote effective transfer of excited electrons from g‐C3N4to TiO2.This enhancement was responsible for the improved photoactivity of the P-O bridged TiO2/g‐C3N4nanocomposite,which exhibited three‐time photocatalytic activity enhancement for2,4‐dichlorophenol degradation and CO2reduction compared with bare g‐C3N4.Furthermore,radical‐trapping experiments revealed that the·OH species formed as hole‐modulated direct intermediates dominated the photocatalytic degradation of2,4‐dichlorophenol.This work provides a feasible strategy for the design and synthesis of high‐performance g‐C3N4‐based nanocomposite photocatalysts for pollutant degradation and CO2reduction. 展开更多
关键词 TiO2/graphitic carbon nitride nanocompositE Phosphate–oxygen bridge Charge transfer and separation PHOTOCATALYSIS Carbon dioxide conversion
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