We report the fabrication of disposable and flexible Screen-Printed Electrodes (SPEs). This new type of screen-printed electrochemical platform consists of Ag nanoparticles (AgNPs) and graphite composite. For this pur...We report the fabrication of disposable and flexible Screen-Printed Electrodes (SPEs). This new type of screen-printed electrochemical platform consists of Ag nanoparticles (AgNPs) and graphite composite. For this purpose, silver nanoparticles were first synthesized by a chemical reduction method. The morphology and structure of the AgNPs were analyzed using a Scanning Electron Microscope (SEM) and UV-Visible spectroscopy. Graphite was chosen as the working electrode material for the fabrication of a thick-film. The fabrication of a screen-printed hydrogen peroxide biosensor consisting of three electrodes on a polyethylene terephthalate (PET) substrate was performed with a spraying approach (working, counter and reference: enzyme electrode, graphite, pseudo reference: Ag/AgCl). This biosensor was fabricated by immobilizing the peroxidase enzyme (HRP) in a Titania sol-gel membrane which was obtained through a vapor deposition method. The biosensor had electrocatalytic activity in the reduction of H2O2 with linear dependence on H2O2 concentration in the range of 10-5 to 10-3 M;the detection limit was 4.5 × 10-6 M.展开更多
Sol-gel titania films were deposited on 316L stainless steel using titanium isopropoxide as a chemical precursor. Dip-coating was performed at withdrawal speeds of 6 mm/min, 30 mm/min, and 60 mm/min. Deposited gel fil...Sol-gel titania films were deposited on 316L stainless steel using titanium isopropoxide as a chemical precursor. Dip-coating was performed at withdrawal speeds of 6 mm/min, 30 mm/min, and 60 mm/min. Deposited gel films were heat treated in air at 80℃, 100℃, 300℃, and 400℃. The structural evolution of the coatings was evaluated by infrared reflection-absorption spectroscopy. The influence of the withdrawal speed and the heat treatment temperature on the structure of the films was studied by varying the reflectance incidence angle during the infrared experiments and by Glow Discharge Spectrometry. Free functional groups were detected. The results indicate the formation of bidendate bridging coordination of carboxylic acid to titanium. Titanium atoms can also be pentacoordinated according to the processing conditions of the films. We observed a tendency of increasing amounts of OH groups with decreasing reflectance incidence angle. The film hardness was measured via Knoop microindenation hardness test.展开更多
In-situ synthesis of ternary europium complex with thenoyltrifluoacetone (TTA) and 1,10-phenanthroline (phen) in titania matrix in the presence of dimethylformamide (DMF) by a sol-gel process was described, which was ...In-situ synthesis of ternary europium complex with thenoyltrifluoacetone (TTA) and 1,10-phenanthroline (phen) in titania matrix in the presence of dimethylformamide (DMF) by a sol-gel process was described, which was confirmed by the luminescence excitation spectra and infrared spectra. The titania gel that contains europium complex exhibits Eu3+ characteristic emission bands and presents a longer fluorescence lifetime than the pure complexes dissolved in ethanol solution. The concentration effect on the luminescence intensity was also investigated.展开更多
The composite films consisting of the titania gel impregnated with hydroxyapatite (HAP) submicron particles were prepared on commercial Ti6A14V plates processed by a sol-gel route. HAP powders were synthesized based...The composite films consisting of the titania gel impregnated with hydroxyapatite (HAP) submicron particles were prepared on commercial Ti6A14V plates processed by a sol-gel route. HAP powders were synthesized based on wet chemical precipitation method with Ca(NO3)2.4H2O and (NH4)2HPO4 as starting reagents. After being calcined at 900℃, HAP powders were ultrasonically scattered in ethanol to produce HAP sol. The titania sol was prepared using titanium (IV) isopropoxide {Ti[OCH(CH3)2]4} as precursor. Both the titania sol and the HAP/titania mixture were sequentially spin-coated on the substrates and calcined at various temperatures. The characteristics and mechanical adhesion of the composite films were investigated. The results show that the as-prepared films are dense, homogeneous, well-crystallized, and there is a good interfacial adhesion between the film and the substrate. The in vitro bioactivities of these films were discussed based on the analysis of the variations of Ca and P concentrations in the simulated body fluid and their surface morphologies against immersion time.展开更多
Titania sol has been prepared by the sol-gel process with Ti(OC4H9)4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into th...Titania sol has been prepared by the sol-gel process with Ti(OC4H9)4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into the nanostructure TiO2. After TiO2 and rare earth doped TiO2 powders were calcined at 400℃, 500℃, 600℃, 700℃ and 800℃ respectively, the characteristic analyses of the TiO2 samples were studied by UV-VIS, XRD and TEM etc. It was found that there are some stringer absorption peaks at 200 - 325 nm. The rare earth doping can increase the phase transition temperature convertin8 anatase phase into rutile phase, can decrease the grain size of TiO2particles and can improve the ann-UV capacity of the coating fabrics.展开更多
Objective of this study was to develope low temperature sol-gel coatings for shape memory metal (NiTi) and evaluate their biocompatibility on NiTi suture material. A series of low temperature TiO2 and TiO2-SiO2 sol-ge...Objective of this study was to develope low temperature sol-gel coatings for shape memory metal (NiTi) and evaluate their biocompatibility on NiTi suture material. A series of low temperature TiO2 and TiO2-SiO2 sol-gel coatings were prepared on glass substrates. The silica content of TiO2-SiO2 coatings ranged from 0 to 30 mol%. The coatings were also prepared with polyethyleneglycol (PEG). The contact angle and photocatalytic activity measurements were used to evaluate the surface properties of the coatings. Stability of the coatings was tested in simulated body fluid (SBF). The TiO2-SiO2 90/10 film made with PEG was more hydrophilic, showed photocatalytic activity and was crack-free after the SBF test, thus it was chosen to animal experiment as a new experimental coating. Uncoated NiTi suture and the suture coated with high temperature TiO2 were used as reference materials. NiTi sutures were inserted subcutaneously on the back of rat for four weeks. In routine histological examinations all materials showed good biocompatibility with mild inflammatory cell reaction. No significant differences in the soft tissue response among the materials were observed. Both the high and new low temperature processed sol-gel coatings remained attached on the sutures confirming the suitability of the coating technique on thin NiTi sutures.展开更多
A stacked Si/SiO_(x)/C composite anode material with carbon-coated structure was prepared by sol-gel method combined with carbothermal reduction using organic silicon.The results of X-ray diffractometry, scanning elec...A stacked Si/SiO_(x)/C composite anode material with carbon-coated structure was prepared by sol-gel method combined with carbothermal reduction using organic silicon.The results of X-ray diffractometry, scanning electron microscopy, and elemental analysis show that the Si/SiO_(x)/C material is a secondary particle with a porous micronanostructure, and the presence of nanometer silicon does not affect the carbothermal reduction and carbon coating.Electrochemical test results indicate that the specific capacity and first coulombic efficiency of SiO_(x)/C composite with nanometer silicon can be increased to 1 946.05 mAh/g and 76.49%,respectively.The reversible specific capacity of Si/SiO_(x)/C material blended with graphite is 749.69 mAh/g after 100 cycles at a current density of 0.1 C,and the capacity retention rate is up to 89.03%.Therefore, the composite has excellent electrochemical cycle stability.展开更多
This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & sil...This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.展开更多
Titania films with nano-sized pores were prepared on the NaOH?HCl pretreated NiTi alloy substrate by sol?gel method.A crack-free film is obtained for the sample with a dense inner layer and a porous outside layer(s...Titania films with nano-sized pores were prepared on the NaOH?HCl pretreated NiTi alloy substrate by sol?gel method.A crack-free film is obtained for the sample with a dense inner layer and a porous outside layer(sample TC1+1).The X-ray diffraction shows that the titania films are composed of anatase,and a little Ni4Ti3 phase in the heat treated substrate is also detected.The X-ray photoelectron spectroscopy results indicate that the titania film completely covered the NiTi substrate for sample TC1+1.The sample TC1+1 is hydrophilic with a contact angle about 20°,and UV illumination treatment for 15 min further decreases the contact angle to(9.2±3.2)°.The potentiodynamic polarization test in 0.9% NaCl solution reveals a better corrosion resistance of sample TC1+1 than the polished NiTi sample.展开更多
A new technique was developed for the conversion of high titania slag,containing 70%-75% TiO2 and with MgO,FeO,CaO,Al2O3 and SiO2 as main impurities,into a synthetic rutile,90%-95% TiO2,which satisfies the requirement...A new technique was developed for the conversion of high titania slag,containing 70%-75% TiO2 and with MgO,FeO,CaO,Al2O3 and SiO2 as main impurities,into a synthetic rutile,90%-95% TiO2,which satisfies the requirements for fluidizing chlorination process with respect to impurity contents.After a pre-oxidation at around 1 042 ℃ and a heat-treatment above 1 510 ℃,the Ti components in high titania slag can be enriched into the rutile phase which can precipitate and grow,and can be separated with dilute hydrochloric and sulfuric acid,respectively.The results show that the average crystal size of rutile phase is over 25 μm,and the synthetic rutile containing more than 95% TiO2 can be produced by selective leaching.展开更多
We demonstrate the synthesis of C-Cl-codoped titania/attapulgite(TiO2/ATT) composites containing a mixture of TiO2 phases by a facile sol-gel method at 70 ℃ using titanium tetraisopropoxide as the TiO2 precursor an...We demonstrate the synthesis of C-Cl-codoped titania/attapulgite(TiO2/ATT) composites containing a mixture of TiO2 phases by a facile sol-gel method at 70 ℃ using titanium tetraisopropoxide as the TiO2 precursor and ATT as a support for the TiO2 nanoparticles.The photocatalytic activity of the C-Cl-codoped TiO2/ATT composites with mixed anatase/brookite/rutile phases obtained at pH= 3.0 was much higher than that of commercially available Degussa P25 for the photocatalytic degradation of acid red G under visible-light irradiation.The excellent photocatalytic activity of the developed composite originates from the nonmetal codoping,which extends the absorption edge of TiO2 into visible region,and the presence of multiple phases,which slow the recombination of photoexcited electron/hole pairs.The formation of hydroxyl radicals during the photocatalytic degradation process was detected by photoluminescence probing using terephthalic acid.A mechanism for photocatalysis over the C-Cl-codoped TiO2/ATT composites was proposed.展开更多
文摘We report the fabrication of disposable and flexible Screen-Printed Electrodes (SPEs). This new type of screen-printed electrochemical platform consists of Ag nanoparticles (AgNPs) and graphite composite. For this purpose, silver nanoparticles were first synthesized by a chemical reduction method. The morphology and structure of the AgNPs were analyzed using a Scanning Electron Microscope (SEM) and UV-Visible spectroscopy. Graphite was chosen as the working electrode material for the fabrication of a thick-film. The fabrication of a screen-printed hydrogen peroxide biosensor consisting of three electrodes on a polyethylene terephthalate (PET) substrate was performed with a spraying approach (working, counter and reference: enzyme electrode, graphite, pseudo reference: Ag/AgCl). This biosensor was fabricated by immobilizing the peroxidase enzyme (HRP) in a Titania sol-gel membrane which was obtained through a vapor deposition method. The biosensor had electrocatalytic activity in the reduction of H2O2 with linear dependence on H2O2 concentration in the range of 10-5 to 10-3 M;the detection limit was 4.5 × 10-6 M.
基金financial support from the Minas Gerais Research Agency(Fapemig),Brazilian Research Agency(CNPq),Brazilian Graduate Agency(CAPES),Minerals and Metallurgy Pole of Excellence of The Minas Gerais State,and The National Institute of Science and Technology on Mineral Resources,Water,and Biodiversity(Acqua).
文摘Sol-gel titania films were deposited on 316L stainless steel using titanium isopropoxide as a chemical precursor. Dip-coating was performed at withdrawal speeds of 6 mm/min, 30 mm/min, and 60 mm/min. Deposited gel films were heat treated in air at 80℃, 100℃, 300℃, and 400℃. The structural evolution of the coatings was evaluated by infrared reflection-absorption spectroscopy. The influence of the withdrawal speed and the heat treatment temperature on the structure of the films was studied by varying the reflectance incidence angle during the infrared experiments and by Glow Discharge Spectrometry. Free functional groups were detected. The results indicate the formation of bidendate bridging coordination of carboxylic acid to titanium. Titanium atoms can also be pentacoordinated according to the processing conditions of the films. We observed a tendency of increasing amounts of OH groups with decreasing reflectance incidence angle. The film hardness was measured via Knoop microindenation hardness test.
文摘In-situ synthesis of ternary europium complex with thenoyltrifluoacetone (TTA) and 1,10-phenanthroline (phen) in titania matrix in the presence of dimethylformamide (DMF) by a sol-gel process was described, which was confirmed by the luminescence excitation spectra and infrared spectra. The titania gel that contains europium complex exhibits Eu3+ characteristic emission bands and presents a longer fluorescence lifetime than the pure complexes dissolved in ethanol solution. The concentration effect on the luminescence intensity was also investigated.
基金This work was financially supported by the National Natural Science Foundation of China (No.50235020).
文摘The composite films consisting of the titania gel impregnated with hydroxyapatite (HAP) submicron particles were prepared on commercial Ti6A14V plates processed by a sol-gel route. HAP powders were synthesized based on wet chemical precipitation method with Ca(NO3)2.4H2O and (NH4)2HPO4 as starting reagents. After being calcined at 900℃, HAP powders were ultrasonically scattered in ethanol to produce HAP sol. The titania sol was prepared using titanium (IV) isopropoxide {Ti[OCH(CH3)2]4} as precursor. Both the titania sol and the HAP/titania mixture were sequentially spin-coated on the substrates and calcined at various temperatures. The characteristics and mechanical adhesion of the composite films were investigated. The results show that the as-prepared films are dense, homogeneous, well-crystallized, and there is a good interfacial adhesion between the film and the substrate. The in vitro bioactivities of these films were discussed based on the analysis of the variations of Ca and P concentrations in the simulated body fluid and their surface morphologies against immersion time.
文摘Titania sol has been prepared by the sol-gel process with Ti(OC4H9)4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into the nanostructure TiO2. After TiO2 and rare earth doped TiO2 powders were calcined at 400℃, 500℃, 600℃, 700℃ and 800℃ respectively, the characteristic analyses of the TiO2 samples were studied by UV-VIS, XRD and TEM etc. It was found that there are some stringer absorption peaks at 200 - 325 nm. The rare earth doping can increase the phase transition temperature convertin8 anatase phase into rutile phase, can decrease the grain size of TiO2particles and can improve the ann-UV capacity of the coating fabrics.
基金supported in part by the National Technology Agency of Finland(40222/05,40171/06)supported by the Biomaterial and Tissue Engineering Graduate School in Finland
文摘Objective of this study was to develope low temperature sol-gel coatings for shape memory metal (NiTi) and evaluate their biocompatibility on NiTi suture material. A series of low temperature TiO2 and TiO2-SiO2 sol-gel coatings were prepared on glass substrates. The silica content of TiO2-SiO2 coatings ranged from 0 to 30 mol%. The coatings were also prepared with polyethyleneglycol (PEG). The contact angle and photocatalytic activity measurements were used to evaluate the surface properties of the coatings. Stability of the coatings was tested in simulated body fluid (SBF). The TiO2-SiO2 90/10 film made with PEG was more hydrophilic, showed photocatalytic activity and was crack-free after the SBF test, thus it was chosen to animal experiment as a new experimental coating. Uncoated NiTi suture and the suture coated with high temperature TiO2 were used as reference materials. NiTi sutures were inserted subcutaneously on the back of rat for four weeks. In routine histological examinations all materials showed good biocompatibility with mild inflammatory cell reaction. No significant differences in the soft tissue response among the materials were observed. Both the high and new low temperature processed sol-gel coatings remained attached on the sutures confirming the suitability of the coating technique on thin NiTi sutures.
文摘A stacked Si/SiO_(x)/C composite anode material with carbon-coated structure was prepared by sol-gel method combined with carbothermal reduction using organic silicon.The results of X-ray diffractometry, scanning electron microscopy, and elemental analysis show that the Si/SiO_(x)/C material is a secondary particle with a porous micronanostructure, and the presence of nanometer silicon does not affect the carbothermal reduction and carbon coating.Electrochemical test results indicate that the specific capacity and first coulombic efficiency of SiO_(x)/C composite with nanometer silicon can be increased to 1 946.05 mAh/g and 76.49%,respectively.The reversible specific capacity of Si/SiO_(x)/C material blended with graphite is 749.69 mAh/g after 100 cycles at a current density of 0.1 C,and the capacity retention rate is up to 89.03%.Therefore, the composite has excellent electrochemical cycle stability.
文摘This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.
基金Project(xjj2011096)supported by the Fundamental Research Fund for the Central Universities,ChinaProject(201107)supported by the Open Project Program of State Key Laboratory of Metastable Materials Science and Technology,ChinaProject(50901058)supported by the National Natural Science Foundation of China
文摘Titania films with nano-sized pores were prepared on the NaOH?HCl pretreated NiTi alloy substrate by sol?gel method.A crack-free film is obtained for the sample with a dense inner layer and a porous outside layer(sample TC1+1).The X-ray diffraction shows that the titania films are composed of anatase,and a little Ni4Ti3 phase in the heat treated substrate is also detected.The X-ray photoelectron spectroscopy results indicate that the titania film completely covered the NiTi substrate for sample TC1+1.The sample TC1+1 is hydrophilic with a contact angle about 20°,and UV illumination treatment for 15 min further decreases the contact angle to(9.2±3.2)°.The potentiodynamic polarization test in 0.9% NaCl solution reveals a better corrosion resistance of sample TC1+1 than the polished NiTi sample.
基金Project(FMRU2007K10)supported by the Open Research Fund of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,China
文摘A new technique was developed for the conversion of high titania slag,containing 70%-75% TiO2 and with MgO,FeO,CaO,Al2O3 and SiO2 as main impurities,into a synthetic rutile,90%-95% TiO2,which satisfies the requirements for fluidizing chlorination process with respect to impurity contents.After a pre-oxidation at around 1 042 ℃ and a heat-treatment above 1 510 ℃,the Ti components in high titania slag can be enriched into the rutile phase which can precipitate and grow,and can be separated with dilute hydrochloric and sulfuric acid,respectively.The results show that the average crystal size of rutile phase is over 25 μm,and the synthetic rutile containing more than 95% TiO2 can be produced by selective leaching.
基金supported by the National Basic Research Program of China (973 Program, 2007CB613302)the Natural Science Foundation of Hubei Province (2016CFA078)~~
文摘We demonstrate the synthesis of C-Cl-codoped titania/attapulgite(TiO2/ATT) composites containing a mixture of TiO2 phases by a facile sol-gel method at 70 ℃ using titanium tetraisopropoxide as the TiO2 precursor and ATT as a support for the TiO2 nanoparticles.The photocatalytic activity of the C-Cl-codoped TiO2/ATT composites with mixed anatase/brookite/rutile phases obtained at pH= 3.0 was much higher than that of commercially available Degussa P25 for the photocatalytic degradation of acid red G under visible-light irradiation.The excellent photocatalytic activity of the developed composite originates from the nonmetal codoping,which extends the absorption edge of TiO2 into visible region,and the presence of multiple phases,which slow the recombination of photoexcited electron/hole pairs.The formation of hydroxyl radicals during the photocatalytic degradation process was detected by photoluminescence probing using terephthalic acid.A mechanism for photocatalysis over the C-Cl-codoped TiO2/ATT composites was proposed.