Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electr...Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.展开更多
SnO2-CuO nanocomposite powders were prepared by chemical coprecipitation method using SnCl4·5H2O, NH3·H2O and Cu(NO3)2·3H2O as raw materials. The powders were characterized by thermogravimertric(TG) ana...SnO2-CuO nanocomposite powders were prepared by chemical coprecipitation method using SnCl4·5H2O, NH3·H2O and Cu(NO3)2·3H2O as raw materials. The powders were characterized by thermogravimertric(TG) analysis and differential thermal analysis(DTA), X-ray diffraction(XRD), and scanning electron microscope(SEM). The electrochemical properties of SnO2-CuO and undoped SnO2 powders as anode materials of lithium ion batteries were investigated comparatively by galvanostatic charge-discharge experiments and AC impedance. The results show that SnO2-CuO nanocomposite powders with the average particle size of 87 nm can be obtained by this method. The structure of SnO2 does not change with the introduction of CuO, but the average particle size of nano-SnO2 decreases. SnO2-CuO nanocomposite powders show a reversible capacity of 752 mA·h/g and better cycleability compared with nano-SnO2. The capacity retention rates after 60 cycles of nano-SnO2-CuO and SnO2 are 93.6% and 92.0% at the charge- discharge rate of 0.1 C, respectively, which suggests that the introduction of CuO into SnO2 can improve the cycleability of nano- SnO2.展开更多
An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horiz...An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)substrate.The CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination conditions.The devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light illuminations.The maximum response of the devices is observed at 300 nm for an illumination power of 10 W.The response and recovery times were calculated as 86 ms and 78 ms,respectively.Moreover,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination conditions.The main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the devices.Under illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)interface.These characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality.展开更多
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
An innovative photocatalyst, Carbon nanotube （CNT） supported Ce-TiO2 nanocomposite was successfully synthesized via modi-fied sol gel method and investigated in a batch reactor for abolition of phenol under UV light...An innovative photocatalyst, Carbon nanotube （CNT） supported Ce-TiO2 nanocomposite was successfully synthesized via modi-fied sol gel method and investigated in a batch reactor for abolition of phenol under UV light spectrum. Characterization of catalyst micro-structure and internal properties were done by means of X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET）, scanning electron micros-copy （SEM）, transmission electron microscopy （TEM） and UV-vis diffuse reflectance spectra （DRS）. Ce doping can inhibit phase transfor-mation from anatase to rutile and eliminate the recombination of electron-hole pairs in the catalyst. The presence of CNT in TiO2 composite can both increase the photoactivity under UV and change surface properties to achieve sensitivity to visible light. The optimum mass ratio of CNT support and cerium （Ce） dopant in TiO2 was the prominent factor to harvest CNT/Ce-TiO2 photocatalyst nanocomposite. The results demonstrated that optimum mass ratio of CNT：TiO2：Ce was 0.02：1.0：0.06, which resulted in the great performance of the photocatalyst to de-grade about 94% of phenol in a 50 mg/L solution in only 3 h. In this paper, dissimilar role of CNT support and Ce dopant in the TiO2 photo-catalysis of phenol was also discussed.展开更多
Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techn...Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.展开更多
Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA...Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA, XRD, H2-TPR and XPS. The catalytic activity of the CuO/TiO2-SnO2 catalysts was markedly depended on the loading of CuO, and the optimum CuO loading was 8 wt.% （Tloo = 80 ℃）. The CuO/TiO2-SnO2 catalysts exhibited much higher catalytic activity than the CuO/TiO2 and CuO/SnO2 catalysts. H2-TPR result indicated that a large amount of CuO formed the active site for CO oxidation in 8 wt.% CuO/TiO2-SnO2 catalyst.展开更多
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
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
Titanium dioxide/ kaolinite nanocomposite was prepared by the sol-gel method, with layered kaolinite as a substrate and Ti （ OC4H9 ）4 as a precursor. The effects of hydrolysis, drying and calcination on the producti...Titanium dioxide/ kaolinite nanocomposite was prepared by the sol-gel method, with layered kaolinite as a substrate and Ti （ OC4H9 ）4 as a precursor. The effects of hydrolysis, drying and calcination on the production of nanometric titanium dioxide were discussed. The optimal conditions for preparation were＂ bbtained through experiments. The 1- 10 nrn thick monolayer anatase nano TiO2 crystal was produced under the conditions as follows： hydrolyzed at 37-42 ℃ for 4 h, dried at 70-80 ℃ for 1 h, and calcined at 550-650℃ for 3 h. The rate of degradation of 40 mg/ L azo dye and 20 mg/ L acid red dye can reuch 96% and 81.45%, respectively.展开更多
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
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
This work is focused on the combination of two building-blocks, nanocrystalline TiO2 particles and polyaniline conductive films （PAni）. The preparation of new nanostructured composite materials, displaying electron-...This work is focused on the combination of two building-blocks, nanocrystalline TiO2 particles and polyaniline conductive films （PAni）. The preparation of new nanostructured composite materials, displaying electron- and proton-conductive properties, to be used for the fabrication of new and superior energy storage devices was envisaged. The semiconducting TiO2 nanoparticles were obtained by means of a hydrothermal route. The PAni films were prepared on glassy carbon electrodes by electrochemical polymerization, under potential dynamic conditions. After characterization by X-ray diffraction, transmission electron microscopy or scanning electron microscopy and electrochemical techniques, the nanocrystalline particles were immobilized in the polymer matrix. The incorporation of the TiO2 was achieved using two distinct approaches： during the polymer growth or by deposition over previously prepared PAni films. The results demonstrate that the PAni morphology depends on the experimental conditions used during the polymer growth. After TiO2 immobilization, the best electrochemical response was obtained for the nanocomposite structure produced through the TiO2 incorporation after the PAni film synthesis. The modified electrodes were structurally and morphologically characterized and their electro-catalytic activity towards the hydrogen evolution reaction was analyzed. A new electrochemical performance related with the oxidation of molecular hydrogen entrapped in the PAni-TiO2 matrix was observed for the modified electrode after TiO2 incorporation. This behavior can be directly associated with the synergetic combination of the TiO2 and PAni, and is dependent on the amount of the semiconductor.展开更多
Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and super...Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties.When the substrate temperature increases from room temperature to 400℃,Co particles gradually grow,and the degree of Co oxidation significantly decreases.Consequently,the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400℃.At a high substrate temperature,conductive pathways form among some of the clustered Co particles.Thus,resistivity rapidly declines from 1600 to 76μΩ·m.The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76μΩ·m.These results reveal that the obtained nanocomposite films have low Co oxidation,high magnetization and magnetoresistance at room temperature.展开更多
We reported a facile preparation of a uniform decoration of spherical n-type SnO2 by p-type CuO nanopa rticles as well as their utilization for enhanced performance on toluene gas detection.CuO nanoparticles and spher...We reported a facile preparation of a uniform decoration of spherical n-type SnO2 by p-type CuO nanopa rticles as well as their utilization for enhanced performance on toluene gas detection.CuO nanoparticles and spherical SnO2 were synthesized by a facile non-hydrolytic solvothermal reaction,which could easily control their morphology.A uniform CuO nanoparticles decoration onto spherical SnO2 was achieved by a simple sonication and vigorous stirring at room tempe rature.We revealed orga nic solvents used in the oxide synthesis had a considerable influence on its surface charge that was beneficial for a uniformly electrostatic self-decoration between positively charged p-type CuO nanoparticles and negatively charged n-type spherical SnO2.Interestingly,CuO was partially reduced to Cu metal during high concentration of toluene exposure destroying p-n contact and developing new metal-semiconductor contact so-called ohmic junction,resulting in extraordinarily responsive and selective to toluene gas at 400℃as compared to a single p-CuO and n-SnO2.It was also found that the amount of particle decoration had an influence on sensor response and resistance.The optimum amount of CuO nanoparticle decoration was0.1 mmol on 0.5 mmol SnO2.The re s ponse(S=Ra/Rg)and selectivity of CuO/S nO2 based material toward the exposure of 75 ppm toluene had reached to such high as 540 and 5,respectively.The effect of p-n heterojunction and metal-semiconductor contact on the gas sensing mechanism of p-type CuO/n-type SnO2 was discussed.Furthermore,by decorating with CuO nanoparticles,CuO/SnO2 morphology was well-maintained after gas sensing evaluation demonstrated its excellency for high temperature toluene gas sensor application.展开更多
Hexagonal NaYF4:Yb3+,Er3+ (β-NaYF4:Yb3+,Er3+) nanoparticles supported on TiO2 nanobelts were prepared using two-step pro- cedures of ion-exchangeable process and hydrothermal treatment: layered titanate nanobelts wer...Hexagonal NaYF4:Yb3+,Er3+ (β-NaYF4:Yb3+,Er3+) nanoparticles supported on TiO2 nanobelts were prepared using two-step pro- cedures of ion-exchangeable process and hydrothermal treatment: layered titanate nanobelts were first ion-exchanged with Y3+, Yb3+ and Er3+ cations to produce titanate nanobelts with these cations, and then, the product nanobelts in NaY solution were treated under hydrothermal con- dition to transform into anatase TiO2 nanobelts supported with β-NaYF4:Yb3+,Er3+ nanoparticles. The final p...展开更多
CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized b...CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized by XRD, BET specific surface area, ESEM and EDS analysis. This synthetic method provides several advantages such as simple work-up procedures, minimal amount of waste generated, short reaction time, and high yields of products.展开更多
以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti ...以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti O2 做了简单对比 .结果表明 :所制 Ti O2 / Sn O2 样品为包覆型结构 ,由锐钛矿型 Ti O2 金红石型 Sn O2 组成 ,与 Sn O2 及 Ti O2 晶体粉末相比所制 Ti O2 / Sn O2 包覆粒子光催化活性得到明显提高 .展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51072141)the scientific research projects of Education Department of Hubei province (D20141503)the President Foundation of Wuhan Institute of Technology (No. 2014029)
文摘Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.
基金Project(05C140) supported by the Scientific Research Fund of Hunan Provincial Education Department
文摘SnO2-CuO nanocomposite powders were prepared by chemical coprecipitation method using SnCl4·5H2O, NH3·H2O and Cu(NO3)2·3H2O as raw materials. The powders were characterized by thermogravimertric(TG) analysis and differential thermal analysis(DTA), X-ray diffraction(XRD), and scanning electron microscope(SEM). The electrochemical properties of SnO2-CuO and undoped SnO2 powders as anode materials of lithium ion batteries were investigated comparatively by galvanostatic charge-discharge experiments and AC impedance. The results show that SnO2-CuO nanocomposite powders with the average particle size of 87 nm can be obtained by this method. The structure of SnO2 does not change with the introduction of CuO, but the average particle size of nano-SnO2 decreases. SnO2-CuO nanocomposite powders show a reversible capacity of 752 mA·h/g and better cycleability compared with nano-SnO2. The capacity retention rates after 60 cycles of nano-SnO2-CuO and SnO2 are 93.6% and 92.0% at the charge- discharge rate of 0.1 C, respectively, which suggests that the introduction of CuO into SnO2 can improve the cycleability of nano- SnO2.
基金CSIR-09/0973(11599)/2021-EMR-I and SERB(Project no:CRG/2021/000255),Department of Science and Technology,Govt.of India。
文摘An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)substrate.The CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination conditions.The devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light illuminations.The maximum response of the devices is observed at 300 nm for an illumination power of 10 W.The response and recovery times were calculated as 86 ms and 78 ms,respectively.Moreover,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination conditions.The main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the devices.Under illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)interface.These characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality.
基金Project(50903023) supported by the National Natural Science Foundation of ChinaProject(HEUCF201210005) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2010RFQXG037) supported by Harbin Special Fund for Innovation Talents of Science and Technology,China
文摘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.
基金Project supported by Research University Grant Scheme (Project A/C No.814004)the Malaysian Technology Development Corporation (MTDC) under the Commercialization of Research and Development Fund (CRDF) (MBF065-USM/05)
文摘An innovative photocatalyst, Carbon nanotube （CNT） supported Ce-TiO2 nanocomposite was successfully synthesized via modi-fied sol gel method and investigated in a batch reactor for abolition of phenol under UV light spectrum. Characterization of catalyst micro-structure and internal properties were done by means of X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET）, scanning electron micros-copy （SEM）, transmission electron microscopy （TEM） and UV-vis diffuse reflectance spectra （DRS）. Ce doping can inhibit phase transfor-mation from anatase to rutile and eliminate the recombination of electron-hole pairs in the catalyst. The presence of CNT in TiO2 composite can both increase the photoactivity under UV and change surface properties to achieve sensitivity to visible light. The optimum mass ratio of CNT support and cerium （Ce） dopant in TiO2 was the prominent factor to harvest CNT/Ce-TiO2 photocatalyst nanocomposite. The results demonstrated that optimum mass ratio of CNT：TiO2：Ce was 0.02：1.0：0.06, which resulted in the great performance of the photocatalyst to de-grade about 94% of phenol in a 50 mg/L solution in only 3 h. In this paper, dissimilar role of CNT support and Ce dopant in the TiO2 photo-catalysis of phenol was also discussed.
基金financially supported by the University of Tabriz
文摘Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.
基金supported by the National Natural Science Foundation of China (20771061 and 20871071)the 973 Program (2005CB623607)Science and Technology Commission Foundation of Tianjin (08JCYBJC00100 and 09JCYBJC03600)
文摘Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA, XRD, H2-TPR and XPS. The catalytic activity of the CuO/TiO2-SnO2 catalysts was markedly depended on the loading of CuO, and the optimum CuO loading was 8 wt.% （Tloo = 80 ℃）. The CuO/TiO2-SnO2 catalysts exhibited much higher catalytic activity than the CuO/TiO2 and CuO/SnO2 catalysts. H2-TPR result indicated that a large amount of CuO formed the active site for CO oxidation in 8 wt.% CuO/TiO2-SnO2 catalyst.
文摘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.
基金Supported by the National Basic Research Program of China("973"Program,No.2014CB239300,No.2012CB720100)National Natural Science Foundation of China(No.21406164,No.21466035)Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20110032110037,No.20130032120019)
文摘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.
基金Funded by National "973" Plan Research Project ( No.2004CB619204) and Educational Ministry Scientific and Technologi-cal Research Key Project (No.02052)
文摘Titanium dioxide/ kaolinite nanocomposite was prepared by the sol-gel method, with layered kaolinite as a substrate and Ti （ OC4H9 ）4 as a precursor. The effects of hydrolysis, drying and calcination on the production of nanometric titanium dioxide were discussed. The optimal conditions for preparation were＂ bbtained through experiments. The 1- 10 nrn thick monolayer anatase nano TiO2 crystal was produced under the conditions as follows： hydrolyzed at 37-42 ℃ for 4 h, dried at 70-80 ℃ for 1 h, and calcined at 550-650℃ for 3 h. The rate of degradation of 40 mg/ L azo dye and 20 mg/ L acid red dye can reuch 96% and 81.45%, respectively.
基金supported by the National Natural Science Foundation of China(U1401245,91622119)the Program for Innovative Research Team in Chinese Universities(IRT1237)+1 种基金the Research Project of Chinese Ministry of Education(213011A)the Science Foundation for Excellent Youth of Harbin City of China(2014RFYXJ002)~~
文摘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.
基金This work was supported by the National and Zhejiang Provincial Natural Science Foundation of China (No. 59773012).
文摘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.
基金supported by FCT-Fundacao para a Ciencia e Tecnologia under the project PTDC/CTM NAN/113021/2009O.C.Monteiro acknowledges PEst-OE/QUI/UI0612/2013 and Programme Ciencia 2007
文摘This work is focused on the combination of two building-blocks, nanocrystalline TiO2 particles and polyaniline conductive films （PAni）. The preparation of new nanostructured composite materials, displaying electron- and proton-conductive properties, to be used for the fabrication of new and superior energy storage devices was envisaged. The semiconducting TiO2 nanoparticles were obtained by means of a hydrothermal route. The PAni films were prepared on glassy carbon electrodes by electrochemical polymerization, under potential dynamic conditions. After characterization by X-ray diffraction, transmission electron microscopy or scanning electron microscopy and electrochemical techniques, the nanocrystalline particles were immobilized in the polymer matrix. The incorporation of the TiO2 was achieved using two distinct approaches： during the polymer growth or by deposition over previously prepared PAni films. The results demonstrate that the PAni morphology depends on the experimental conditions used during the polymer growth. After TiO2 immobilization, the best electrochemical response was obtained for the nanocomposite structure produced through the TiO2 incorporation after the PAni film synthesis. The modified electrodes were structurally and morphologically characterized and their electro-catalytic activity towards the hydrogen evolution reaction was analyzed. A new electrochemical performance related with the oxidation of molecular hydrogen entrapped in the PAni-TiO2 matrix was observed for the modified electrode after TiO2 incorporation. This behavior can be directly associated with the synergetic combination of the TiO2 and PAni, and is dependent on the amount of the semiconductor.
基金Project(2016YFE0205700)supported by the National Key Research and Development Program of ChinaProject(18JCYBJC18000)supported by the Natural Science Foundation of Tianjin City,China。
文摘Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties.When the substrate temperature increases from room temperature to 400℃,Co particles gradually grow,and the degree of Co oxidation significantly decreases.Consequently,the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400℃.At a high substrate temperature,conductive pathways form among some of the clustered Co particles.Thus,resistivity rapidly declines from 1600 to 76μΩ·m.The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76μΩ·m.These results reveal that the obtained nanocomposite films have low Co oxidation,high magnetization and magnetoresistance at room temperature.
基金financially supported by the Japan Society for the Promotion of Science(JSPS)Grant-in-Aid for the Scientific Research(KAKENHI)on Innovative Areas“Mixed Anion”(No.16H06439,No.16H06440)by the Dynamic Alliance for Open Innovations Bridging Human,Environment and Materials,the Cooperative Research Program of“Network Joint Research Center for Materials and Devices”。
文摘We reported a facile preparation of a uniform decoration of spherical n-type SnO2 by p-type CuO nanopa rticles as well as their utilization for enhanced performance on toluene gas detection.CuO nanoparticles and spherical SnO2 were synthesized by a facile non-hydrolytic solvothermal reaction,which could easily control their morphology.A uniform CuO nanoparticles decoration onto spherical SnO2 was achieved by a simple sonication and vigorous stirring at room tempe rature.We revealed orga nic solvents used in the oxide synthesis had a considerable influence on its surface charge that was beneficial for a uniformly electrostatic self-decoration between positively charged p-type CuO nanoparticles and negatively charged n-type spherical SnO2.Interestingly,CuO was partially reduced to Cu metal during high concentration of toluene exposure destroying p-n contact and developing new metal-semiconductor contact so-called ohmic junction,resulting in extraordinarily responsive and selective to toluene gas at 400℃as compared to a single p-CuO and n-SnO2.It was also found that the amount of particle decoration had an influence on sensor response and resistance.The optimum amount of CuO nanoparticle decoration was0.1 mmol on 0.5 mmol SnO2.The re s ponse(S=Ra/Rg)and selectivity of CuO/S nO2 based material toward the exposure of 75 ppm toluene had reached to such high as 540 and 5,respectively.The effect of p-n heterojunction and metal-semiconductor contact on the gas sensing mechanism of p-type CuO/n-type SnO2 was discussed.Furthermore,by decorating with CuO nanoparticles,CuO/SnO2 morphology was well-maintained after gas sensing evaluation demonstrated its excellency for high temperature toluene gas sensor application.
基金Project supported by the "973" Basic Research Foundation of China (2006CB932605)the National Natural Science Foundation of China (20976002)
文摘Hexagonal NaYF4:Yb3+,Er3+ (β-NaYF4:Yb3+,Er3+) nanoparticles supported on TiO2 nanobelts were prepared using two-step pro- cedures of ion-exchangeable process and hydrothermal treatment: layered titanate nanobelts were first ion-exchanged with Y3+, Yb3+ and Er3+ cations to produce titanate nanobelts with these cations, and then, the product nanobelts in NaY solution were treated under hydrothermal con- dition to transform into anatase TiO2 nanobelts supported with β-NaYF4:Yb3+,Er3+ nanoparticles. The final p...
基金the Behbahan Khatam Alanbia University of Technology for the partial support of this work
文摘CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized by XRD, BET specific surface area, ESEM and EDS analysis. This synthetic method provides several advantages such as simple work-up procedures, minimal amount of waste generated, short reaction time, and high yields of products.
文摘以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti O2 做了简单对比 .结果表明 :所制 Ti O2 / Sn O2 样品为包覆型结构 ,由锐钛矿型 Ti O2 金红石型 Sn O2 组成 ,与 Sn O2 及 Ti O2 晶体粉末相比所制 Ti O2 / Sn O2 包覆粒子光催化活性得到明显提高 .
