The nanometer and ordinary anatase titanium dioxide(TiO_2) powders were adopted as the sonocatalysts for the degradation of methyl orange used as a model compound for the first time. It was found that the sonocatalyti...The nanometer and ordinary anatase titanium dioxide(TiO_2) powders were adopted as the sonocatalysts for the degradation of methyl orange used as a model compound for the first time. It was found that the sonocatalytic degradation effect of methyl orange in the presence of TiO_2 powder were much better than that without TiO_2, but the sonocatalytic activity of the nanometer anatase TiO_2 particle was obviously higher than that of ordinary anatase TiO_2 particle. Although there are many factors influencing sonocatalytic degradation of methyl orange, the experimental results showed that the best degradation ratio of methyl orange could be obtained when the experimental conditions were: initial concentration 15 mg/L, nanometer anatase TiO_2 adding amount 750 mg/L, ultrasonic frequency 40 kHz, output power 50 W, pH = 3.0 and temperature 40℃ within 150 min. In addition, the catalytic activity of reused nanometer anatase TiO_2 catalyst was also studied and found to decline gradually comparing with initial nanometer anatase TiO_2 catalyst. All experiments indicated that the method of the sonocatalytic degradation of organic pollutants in the presence of TiO_2 powder was an advisable choice for non- or low-transparent organic wastewaters.展开更多
Photocatalytic water splitting(PWS)has attracted widespread attention as a sustainable method for converting solar to green hydrogen energy.So far PWS research has mainly focused on the development of artificial photo...Photocatalytic water splitting(PWS)has attracted widespread attention as a sustainable method for converting solar to green hydrogen energy.So far PWS research has mainly focused on the development of artificial photocatalytic hydrogen production systems for pure water.It is more practically attractive to create systems for seawater,i.e.,to reduce the cost of hydrogen production and make better use of naturally occurring water resources.Herein,brookite,anatase,and rutile TiO_(2)nanoparticles are investigated as photocatalysts to explore the feasibility of such thought and have shown attractive hydrogen production performance under full solar spectrum without any sacrificial agent.It is worth noting that,brookite TiO_(2),has more suitable band gap position and excellent photoelectric properties compared with anatase and rutile TiO_(2),and has higher efficiency and stability in the process of hydrogen production.The photocatalytic hydrogen production rate of brookite TiO_(2)can reach up to 1,476μmol/g/h,the highest value reported for TiO_(2)-based systems and most other photocatalysts in seawater splitting under full spectrum.As the Cl−ions in seawater go through a cycle of oxidation and reduction,no Cl_(2) is detected in the solar hydrogen production from seawater.展开更多
Superlubricity control is of great interest in both industry and scientific research,and several methods have been proposed to achieve this goal.In this work,ultraviolet(UV)light was introduced into titanium dioxide(T...Superlubricity control is of great interest in both industry and scientific research,and several methods have been proposed to achieve this goal.In this work,ultraviolet(UV)light was introduced into titanium dioxide(TiO_(2))and silicon nitride(Si_(3)N_(4))tribosystems to accomplish photoinduced superlubricity.The friction coefficients(COFs)between Si_(3)N_(4) balls and TiO_(2) plates in the mixtures of sulfuric acid(H^(2)SO_(4))solution and glycerol solution were obviously reduced,and the system entered the superlubricity region(COF<0.01)after UV illumination at a speed of 56 mm/s.However,the COF was much larger without UV treatment than that with UV treatment.The formation of silica(SiO_(2))layers on the surfaces of Si_(3)N_(4) balls and the elastohydrodynamic effects were determined to be fundamental to the low friction in this experiment,and the enhancement of the combination between the TiO_(2) surface and the hydroxy group of glycerol by UV illumination was the key to the photoinduced superlubricity in this system.These findings showed one method for achieving superlubricity by introducing a light field that could be further applied to special working conditions.展开更多
We studied the effect of titanium dioxide(TiO_(2))nanoparticles(NPs)on dielectric behavior of Naþion-conducting salt-complexed polymer nanocomposite system formed from a binary polymer blend of poly(ethylene oxid...We studied the effect of titanium dioxide(TiO_(2))nanoparticles(NPs)on dielectric behavior of Naþion-conducting salt-complexed polymer nanocomposite system formed from a binary polymer blend of poly(ethylene oxide)(PEO)and polyvinyl pyrrolidone(PVP),with the addition of both sodium metaperiodate(NaIO_(4))at concentration 10 wt.%and TiO_(2) NPs of size10 nm,at concentrations 1,2,3,4 and 5 wt.%.Free standing nanocomposite PEO/PVP/NaIO_(4)/TiO_(2) films(150m)were characterized at room-temperature by analyzing their complex electrical impedance and dielectric spectra in the range 1 Hz–1 MHz.At the concentration of 3 wt.%of TiO_(2) NPs,both ion conductivity and dielectric permittivity of the PEO/PVP/NaIO_(4)/TiO_(2) ion-conducting dielectrics reach an enhancement by more than one order of magnitude as compared to nanoadditive-free case.展开更多
Titanium dioxide(TiO_(2))was elaborated by four different thermal spray techniques-(i)plasma spraying using a water-stabilized torch,(ii)plasma spraying using a gas-stabilized torch,(iii)high velocity oxy-fuel gun,and...Titanium dioxide(TiO_(2))was elaborated by four different thermal spray techniques-(i)plasma spraying using a water-stabilized torch,(ii)plasma spraying using a gas-stabilized torch,(iii)high velocity oxy-fuel gun,and(iv)oxy-acetylene flame.The porosity of the coatings was studied by optical microscopy,nano-structural features by scanning electron microscopy(SEM),phase composition by X-ray diffraction(XRD);the microhardness,surface roughness and wear resistance were evaluated.The diffuse reflectance was measured by ultra-violet/visible/near-infrared(UV/Vis/NIR)scanning spectrophotometer.The kinetics of photocatalytic degradation of gaseous acetone was measured under a UV lamp with 365 nm wavelength.After all the applied spray processes,the transformation of anatase phase from the initial powders to rutile phase in the coatings occurred.In spite of this transformation,all the coatings exhibited certain photocatalytic activity,which correlated well with their band gap energy calculated from reflectivity.All the coatings offer relatively good mechanical properties and can serve as robust photocatalysts.展开更多
基金Foundation item: The National Natural Science Foundation of China(No. 20371023)
文摘The nanometer and ordinary anatase titanium dioxide(TiO_2) powders were adopted as the sonocatalysts for the degradation of methyl orange used as a model compound for the first time. It was found that the sonocatalytic degradation effect of methyl orange in the presence of TiO_2 powder were much better than that without TiO_2, but the sonocatalytic activity of the nanometer anatase TiO_2 particle was obviously higher than that of ordinary anatase TiO_2 particle. Although there are many factors influencing sonocatalytic degradation of methyl orange, the experimental results showed that the best degradation ratio of methyl orange could be obtained when the experimental conditions were: initial concentration 15 mg/L, nanometer anatase TiO_2 adding amount 750 mg/L, ultrasonic frequency 40 kHz, output power 50 W, pH = 3.0 and temperature 40℃ within 150 min. In addition, the catalytic activity of reused nanometer anatase TiO_2 catalyst was also studied and found to decline gradually comparing with initial nanometer anatase TiO_2 catalyst. All experiments indicated that the method of the sonocatalytic degradation of organic pollutants in the presence of TiO_2 powder was an advisable choice for non- or low-transparent organic wastewaters.
基金the National Natural Science Foundation of China(No.21972028)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000).
文摘Photocatalytic water splitting(PWS)has attracted widespread attention as a sustainable method for converting solar to green hydrogen energy.So far PWS research has mainly focused on the development of artificial photocatalytic hydrogen production systems for pure water.It is more practically attractive to create systems for seawater,i.e.,to reduce the cost of hydrogen production and make better use of naturally occurring water resources.Herein,brookite,anatase,and rutile TiO_(2)nanoparticles are investigated as photocatalysts to explore the feasibility of such thought and have shown attractive hydrogen production performance under full solar spectrum without any sacrificial agent.It is worth noting that,brookite TiO_(2),has more suitable band gap position and excellent photoelectric properties compared with anatase and rutile TiO_(2),and has higher efficiency and stability in the process of hydrogen production.The photocatalytic hydrogen production rate of brookite TiO_(2)can reach up to 1,476μmol/g/h,the highest value reported for TiO_(2)-based systems and most other photocatalysts in seawater splitting under full spectrum.As the Cl−ions in seawater go through a cycle of oxidation and reduction,no Cl_(2) is detected in the solar hydrogen production from seawater.
基金the support of the National Natural Science Foundation of China(51922058).
文摘Superlubricity control is of great interest in both industry and scientific research,and several methods have been proposed to achieve this goal.In this work,ultraviolet(UV)light was introduced into titanium dioxide(TiO_(2))and silicon nitride(Si_(3)N_(4))tribosystems to accomplish photoinduced superlubricity.The friction coefficients(COFs)between Si_(3)N_(4) balls and TiO_(2) plates in the mixtures of sulfuric acid(H^(2)SO_(4))solution and glycerol solution were obviously reduced,and the system entered the superlubricity region(COF<0.01)after UV illumination at a speed of 56 mm/s.However,the COF was much larger without UV treatment than that with UV treatment.The formation of silica(SiO_(2))layers on the surfaces of Si_(3)N_(4) balls and the elastohydrodynamic effects were determined to be fundamental to the low friction in this experiment,and the enhancement of the combination between the TiO_(2) surface and the hydroxy group of glycerol by UV illumination was the key to the photoinduced superlubricity in this system.These findings showed one method for achieving superlubricity by introducing a light field that could be further applied to special working conditions.
基金supported by the Ministry of Education and Science of Bulgaria(MESB),through the National Science Fund of Bulgaria(research project No.KP-06-N58/6/2021)Todor Vlakhov gratefully acknowledges the support by the MESB under the National Research Programme,Young scientists and postdoctoral researches-2 approved by DCM 206/07.04.2022.
文摘We studied the effect of titanium dioxide(TiO_(2))nanoparticles(NPs)on dielectric behavior of Naþion-conducting salt-complexed polymer nanocomposite system formed from a binary polymer blend of poly(ethylene oxide)(PEO)and polyvinyl pyrrolidone(PVP),with the addition of both sodium metaperiodate(NaIO_(4))at concentration 10 wt.%and TiO_(2) NPs of size10 nm,at concentrations 1,2,3,4 and 5 wt.%.Free standing nanocomposite PEO/PVP/NaIO_(4)/TiO_(2) films(150m)were characterized at room-temperature by analyzing their complex electrical impedance and dielectric spectra in the range 1 Hz–1 MHz.At the concentration of 3 wt.%of TiO_(2) NPs,both ion conductivity and dielectric permittivity of the PEO/PVP/NaIO_(4)/TiO_(2) ion-conducting dielectrics reach an enhancement by more than one order of magnitude as compared to nanoadditive-free case.
基金This work was supported by the Czech Science Foundation under Project P108/12/1872.
文摘Titanium dioxide(TiO_(2))was elaborated by four different thermal spray techniques-(i)plasma spraying using a water-stabilized torch,(ii)plasma spraying using a gas-stabilized torch,(iii)high velocity oxy-fuel gun,and(iv)oxy-acetylene flame.The porosity of the coatings was studied by optical microscopy,nano-structural features by scanning electron microscopy(SEM),phase composition by X-ray diffraction(XRD);the microhardness,surface roughness and wear resistance were evaluated.The diffuse reflectance was measured by ultra-violet/visible/near-infrared(UV/Vis/NIR)scanning spectrophotometer.The kinetics of photocatalytic degradation of gaseous acetone was measured under a UV lamp with 365 nm wavelength.After all the applied spray processes,the transformation of anatase phase from the initial powders to rutile phase in the coatings occurred.In spite of this transformation,all the coatings exhibited certain photocatalytic activity,which correlated well with their band gap energy calculated from reflectivity.All the coatings offer relatively good mechanical properties and can serve as robust photocatalysts.
