In practical applications,noble metal doping is often used to prepare high performance gas sensors,but more noble metal doping will lead to higher preparation costs.In this study,CeO_(2)/ZnO-Pd with low palladium cont...In practical applications,noble metal doping is often used to prepare high performance gas sensors,but more noble metal doping will lead to higher preparation costs.In this study,CeO_(2)/ZnO-Pd with low palladium content was prepared by ultrasonic method with fast response and high selectivity for acetone sensing.With the same amount of palladium added,the selectivity coefficient of CeO_(2)/ZnO-Pd is 1.88 times higher than that of the stirred sensor.Compared with the pure PdO-doped CeO_(2)/ZnO-PdO material,the content of Pd in CeO_(2)/ZnO-PdO is about 30%of that in CeO_(2)/ZnO-PdO,but the selectivity coefficient for acetone is 2.56 times higher.The CeO_(2)/ZnO-Pd sensor has a higher response(22.54)to 50×10^(−6) acetone at 300℃and the selectivity coefficient is 2.57 times that of the CeO_(2)/ZnO sensor.The sensor has a sub-second response time(0.6 s)and still has a 2.36 response to 330×10^(−9) of acetone.Ultrasonic doping makes Pd particles smaller and increases the contact area with gas.Meanwhile,the composition of n-p-n heterojunction and the synergistic effect of Pd/PdO improve the sensor performance.It shows that ultrasonic Pd doping provides a way to improve the utilization rate of doped metals and prepare highly selective gas sensors.展开更多
The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a...The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity.However,the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now.Herein,the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques,including acetone-temperature-programmed surface reaction,gas chromatography-mass spectrometry,in situ ultraviolet-visible,and ^(13)C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy.A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites.In comparison with the low reaction temperature,a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed,and which could strongly adsorb on the Lewis acidic sites,and thus cause the catalyst deactivation eventually.After a simple calcination,the coke deposits could be easily removed and the catalytic activity could be well restored.展开更多
Dear editor, Isopropanol, also named 2-propanol or isopropyl alcohol(IPA), is a colorless, volatile liquid found in numerous household chemicals, such as cleaners and disinfectants, which typically contain a 70% solut...Dear editor, Isopropanol, also named 2-propanol or isopropyl alcohol(IPA), is a colorless, volatile liquid found in numerous household chemicals, such as cleaners and disinfectants, which typically contain a 70% solution of IPA in water. IPA is also extensively used in industry and laboratories as a solvent.展开更多
Exhaled ammonia(NH_(3))is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualita...Exhaled ammonia(NH_(3))is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH_(3)with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH_(3)product ion peak of(C_(3)H_(6)O)_(4)NH_(4)^(+)(K_(0)=1.45 cm^(2)/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C_(3)H_(6)O)_(2)H^(+)(K_(0)=1.87 cm^(2)/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH_(3)qualitative identification.Moreover,the interference of high humidity and the memory effect of NH_(3)molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92μmol/L with a response time of 40 ms was achieved,and the exhaled NH_(3)profile could be synchronized with the concentration curve of exhaled CO_(2).Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH_(3)of healthy subjects,demonstrating its great potential for clinical disease diagnosis.展开更多
Carbon nanotubes(CNTs)have attracted many researcher's attention in gas sensing field because of their excellent physical and chemical properties.Herein,multi-walled carbon nanotubes(MWCNTs)/ZnSnO_(3)heterostructu...Carbon nanotubes(CNTs)have attracted many researcher's attention in gas sensing field because of their excellent physical and chemical properties.Herein,multi-walled carbon nanotubes(MWCNTs)/ZnSnO_(3)heterostructures have been obtained by a simple hydrothermal method without additional annealing process.The structural and composition information are characterized by x-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and x-ray photoelectron spectroscopy(XPS).The acetone sensing properties of pure MWCNTs,ZnSnO_(3)and MWCNTs/ZnSnO_(3)heterostructures are systematically investigated,respectively.The results show that MWCNTs/ZnSnO_(3)heterostructures have better sensing properties compared with pure MWCNTs and ZnSnO_(3)sample.Specifically,MWCNTs/ZnSnO_(3)heterostructures exhibit not only high responses of 24.1 and rapid response/recovery speed of 1 s/9 s to 100 ppm acetone,but also relatively good repeatability and long-term stability.The enhanced sensing performance is analyzed in detail.In addition,this work provides the experimental and theory basis for synthesis of high-performance MWCNT-based chemical sensors.展开更多
Nickel ferrite nano-powders were prepared by microwave radiating low-temperature solid-state reaction method, and then modified with Ag by dipping method. The crystal structure and morphology of the samples were chara...Nickel ferrite nano-powders were prepared by microwave radiating low-temperature solid-state reaction method, and then modified with Ag by dipping method. The crystal structure and morphology of the samples were characterized by means of X-ray diffraction(XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing properties of the samples were also investigated. The results reveal that the Ag, as amorphous structure, can efficiently prevent the reuniting and growing-up of nanosized NiFe2O4 grains, and 1.5% Ag modified NiFe2O4 sensor has a better sensitivity, up to 43, for acetone gas than 1.5%Ag mixed NiFe2O4 sensor prepared by low-temperature solid-state reaction, at an optimal working voltage of 4.5 V. The quick response time (1 s) and fast recovery time (~10 s) are the main characteristics of this sensor.展开更多
The morphologic changes and growth status of PC12 cells were observed after intervened by different concentrations of methanol, ethanol, acetone, glycerol and the toxic concentrations were ascertained. Four kinds of o...The morphologic changes and growth status of PC12 cells were observed after intervened by different concentrations of methanol, ethanol, acetone, glycerol and the toxic concentrations were ascertained. Four kinds of organic solvents al showed certain cytotoxicity to PC12 cells. Compared with other three kinds of or-ganic solvents, ethanol showed the most obvious cytotoxicity to PC12 cells and the cellviability would be reduced to 60% if the concentration of ethanol was 20 ml/L and the intervention lasted for 24 h. Under the same condition, the reduced per-centages of cellviability for acetone and ethanol were 20% and 15% respectively. Glycerol also showed cytotoxicity to PC12 cells, especial y as the concentration was raised gradual y, but the toxicity was relatively mild. This study would provide refer-ence material for subsequent pharmacological studies.展开更多
Solvothermal reaction of imidazolyl-based synthon with deprotonated adipic acid produced a new coordination complex {[Zn(BIDPE)(hdc)]·2 H;O}n(1). The structure was characterized by single-crystal X-ray crysta...Solvothermal reaction of imidazolyl-based synthon with deprotonated adipic acid produced a new coordination complex {[Zn(BIDPE)(hdc)]·2 H;O}n(1). The structure was characterized by single-crystal X-ray crystallography. It crystallizes in monoclinic, space group C2/m, at 293 K: a = 12.005(2), b = 17.956(3), c = 12.039(2) ?, β = 113.089(3)°, V = 2387.3(7) ?;, Z = 4, Dc = 1.524 g·cm-3, μ(Mo Ka) = 1.082 mm–1 and F(000) = 1136. 5942 reflections were measured and 2180 independent reflections(Rint = 0.0679) were used in further refinement. Complex 1 reveals 1D double-stranded chains containing [Zn;(BIDPE);] and [Zn;(hdc);] metallocyclic rings. The adjacent chains are linked by H-bonding and π···π interactions to form a 3D network. Thermal stability and luminescence property were studied. Interestingly, the luminescent emission of 1 can be quenched by the addition of trace amount of acetone, demonstrating its potential application for sensitive detecting acetone.展开更多
The acetone-sensing properties of the undoped and Pd doped perovskite-type oxides NdFeO3 were investigated from room temperature to 400°C. The perovskite-type NdFeO3 was synthesized by a sol-gel method, and the d...The acetone-sensing properties of the undoped and Pd doped perovskite-type oxides NdFeO3 were investigated from room temperature to 400°C. The perovskite-type NdFeO3 was synthesized by a sol-gel method, and the dopants Pd with the content from 1wt% to 5wt% were implanted into NdFeO3 nanoparticles by thermal diffusion. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques show that NdFeO3 is an orthorhombic structure with the average particle size of about 40 nm. A giant acetone-sensing response of 675.7 is observed when the Pd content in NdFeO3 powders is about 3wt%. The response and recovery time of the sensor to the 5×10–4 acetone gas are 16 and 1 s, respectively. At the same time, it performs a good selectivity to acetone gas and may be a new promising material candidate for the acetone-sensor development.展开更多
Acetone diffusion in polycarbonate was investigated by spin-echo ~1H NMR imaging method at room temperature. The result shows that the diffusion process satisfies Case Ⅱ diffusion. The velocity of diffusion front is ...Acetone diffusion in polycarbonate was investigated by spin-echo ~1H NMR imaging method at room temperature. The result shows that the diffusion process satisfies Case Ⅱ diffusion. The velocity of diffusion front is 13.8nm sec^(-1)(0.05mm/h).展开更多
Ternary Au/Fe2O3-ZnO gas-sensing materials were synthesized by combining co-precipitation and microwave irradiation process.The as-prepared Au/Fe2O3-ZnO was characterized with X-ray diffractometer and scanning electro...Ternary Au/Fe2O3-ZnO gas-sensing materials were synthesized by combining co-precipitation and microwave irradiation process.The as-prepared Au/Fe2O3-ZnO was characterized with X-ray diffractometer and scanning electron microscope,and its gas-sensing performance was measured using a gas-sensor analysis system.The results show that the as-prepared products consist of hexagonal wurtzite ZnO,face-centered cubic gold nanoparticles and orthorhombic Fe2O3crystallines.The Au/Fe2O3-ZnO based sensor has a very high selectivity to ethanol and acetone,and also has high sensitivity(154)at a low working temperature(270°C)and an extremely fast response(1s)against acetone.It is found that the selectivity can be adjusted by Fe2O3content added in the ternary materials.It possesses a worth looking forward prospect to practical applications in acetone detecting and administrating field.展开更多
TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fl...TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.展开更多
In recent years, clinical studies have found that acetone concentration in exhaled breath can be taken as a characteristic marker of diabetes. Metal-oxide-semiconductor (MOS) materials are widely used in acetone gas s...In recent years, clinical studies have found that acetone concentration in exhaled breath can be taken as a characteristic marker of diabetes. Metal-oxide-semiconductor (MOS) materials are widely used in acetone gas sensors due to their low cost, high sensitivity, fast response/recovery time, and easy integration. This paper reviews recent progress in acetone sensors based on MOS materials for diabetes diagnosis. The methods of improving the performance of acetone sensor have been explored for comparison, especially in high humidity conditions. We summarize the current excellent methods of preparations of sensors based on MOSs and hope to provide some help for the progress of acetone sensors in the diagnosis of diabetes.展开更多
Acetone,which is volatile,flammable,toxic,expen- sive and causing serious air pollution,is often used as extracting solvent in the production of powdery soy phospholipid.Recycling and reusing acetone is the key of red...Acetone,which is volatile,flammable,toxic,expen- sive and causing serious air pollution,is often used as extracting solvent in the production of powdery soy phospholipid.Recycling and reusing acetone is the key of reducing the cost of production. Therefore,saving energy and reducing emission when recycling acetone are the most important technologies during the production of phospholipid.On the basis of the productivity of powdery phospholipid being 2.4 t every day,43.2 t acetone is reused every 8 h and the total volume of acetone gas emitted is 450.75 m3 (about 901.5 kg).According to the current price of acetone,the lost money is about 7212 yuan RMB.展开更多
The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)comp...The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.展开更多
基金Project(2023JJ10005)supported by the Natural Science Foundation of Hunan Province,ChinaProjects(51772082,51804106)supported by the National Natural Science Foundation of China。
文摘In practical applications,noble metal doping is often used to prepare high performance gas sensors,but more noble metal doping will lead to higher preparation costs.In this study,CeO_(2)/ZnO-Pd with low palladium content was prepared by ultrasonic method with fast response and high selectivity for acetone sensing.With the same amount of palladium added,the selectivity coefficient of CeO_(2)/ZnO-Pd is 1.88 times higher than that of the stirred sensor.Compared with the pure PdO-doped CeO_(2)/ZnO-PdO material,the content of Pd in CeO_(2)/ZnO-PdO is about 30%of that in CeO_(2)/ZnO-PdO,but the selectivity coefficient for acetone is 2.56 times higher.The CeO_(2)/ZnO-Pd sensor has a higher response(22.54)to 50×10^(−6) acetone at 300℃and the selectivity coefficient is 2.57 times that of the CeO_(2)/ZnO sensor.The sensor has a sub-second response time(0.6 s)and still has a 2.36 response to 330×10^(−9) of acetone.Ultrasonic doping makes Pd particles smaller and increases the contact area with gas.Meanwhile,the composition of n-p-n heterojunction and the synergistic effect of Pd/PdO improve the sensor performance.It shows that ultrasonic Pd doping provides a way to improve the utilization rate of doped metals and prepare highly selective gas sensors.
文摘The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity.However,the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now.Herein,the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques,including acetone-temperature-programmed surface reaction,gas chromatography-mass spectrometry,in situ ultraviolet-visible,and ^(13)C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy.A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites.In comparison with the low reaction temperature,a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed,and which could strongly adsorb on the Lewis acidic sites,and thus cause the catalyst deactivation eventually.After a simple calcination,the coke deposits could be easily removed and the catalytic activity could be well restored.
文摘Dear editor, Isopropanol, also named 2-propanol or isopropyl alcohol(IPA), is a colorless, volatile liquid found in numerous household chemicals, such as cleaners and disinfectants, which typically contain a 70% solution of IPA in water. IPA is also extensively used in industry and laboratories as a solvent.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.:22027804,21974141,and 21904125)Natural Science Foundation of Liaoning Province(Grant Nos.:2022-MS-019 and 2022-MS-016)+2 种基金Science and Technology Innovation Foundation of Dalian(Grant No.:2022JJ13SN096)Dalian Institute of Chemical Physics(Grant Nos.:DICP I202141 and DICP I202144)1+X Program for Large Cohort Study-Clinical Research Incubation Project,The Second Hospital of Dalian Medical University(Project No.:2022DXDL01).
文摘Exhaled ammonia(NH_(3))is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH_(3)with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH_(3)product ion peak of(C_(3)H_(6)O)_(4)NH_(4)^(+)(K_(0)=1.45 cm^(2)/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C_(3)H_(6)O)_(2)H^(+)(K_(0)=1.87 cm^(2)/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH_(3)qualitative identification.Moreover,the interference of high humidity and the memory effect of NH_(3)molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92μmol/L with a response time of 40 ms was achieved,and the exhaled NH_(3)profile could be synchronized with the concentration curve of exhaled CO_(2).Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH_(3)of healthy subjects,demonstrating its great potential for clinical disease diagnosis.
基金Fundamental Research Program of Shanxi Province,China(Grant No.202103021223004)Fundamental Research Fund of Taiyuan University(Grant No.21TYKQ21)。
文摘Carbon nanotubes(CNTs)have attracted many researcher's attention in gas sensing field because of their excellent physical and chemical properties.Herein,multi-walled carbon nanotubes(MWCNTs)/ZnSnO_(3)heterostructures have been obtained by a simple hydrothermal method without additional annealing process.The structural and composition information are characterized by x-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and x-ray photoelectron spectroscopy(XPS).The acetone sensing properties of pure MWCNTs,ZnSnO_(3)and MWCNTs/ZnSnO_(3)heterostructures are systematically investigated,respectively.The results show that MWCNTs/ZnSnO_(3)heterostructures have better sensing properties compared with pure MWCNTs and ZnSnO_(3)sample.Specifically,MWCNTs/ZnSnO_(3)heterostructures exhibit not only high responses of 24.1 and rapid response/recovery speed of 1 s/9 s to 100 ppm acetone,but also relatively good repeatability and long-term stability.The enhanced sensing performance is analyzed in detail.In addition,this work provides the experimental and theory basis for synthesis of high-performance MWCNT-based chemical sensors.
基金Project (2006BS04035) supported by the Youth Scientific Research Foundation of Shandong Province, China
文摘Nickel ferrite nano-powders were prepared by microwave radiating low-temperature solid-state reaction method, and then modified with Ag by dipping method. The crystal structure and morphology of the samples were characterized by means of X-ray diffraction(XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing properties of the samples were also investigated. The results reveal that the Ag, as amorphous structure, can efficiently prevent the reuniting and growing-up of nanosized NiFe2O4 grains, and 1.5% Ag modified NiFe2O4 sensor has a better sensitivity, up to 43, for acetone gas than 1.5%Ag mixed NiFe2O4 sensor prepared by low-temperature solid-state reaction, at an optimal working voltage of 4.5 V. The quick response time (1 s) and fast recovery time (~10 s) are the main characteristics of this sensor.
文摘The morphologic changes and growth status of PC12 cells were observed after intervened by different concentrations of methanol, ethanol, acetone, glycerol and the toxic concentrations were ascertained. Four kinds of organic solvents al showed certain cytotoxicity to PC12 cells. Compared with other three kinds of or-ganic solvents, ethanol showed the most obvious cytotoxicity to PC12 cells and the cellviability would be reduced to 60% if the concentration of ethanol was 20 ml/L and the intervention lasted for 24 h. Under the same condition, the reduced per-centages of cellviability for acetone and ethanol were 20% and 15% respectively. Glycerol also showed cytotoxicity to PC12 cells, especial y as the concentration was raised gradual y, but the toxicity was relatively mild. This study would provide refer-ence material for subsequent pharmacological studies.
基金supported by the National Natural Science Foundation of China(No.21671004,51404006)
文摘Solvothermal reaction of imidazolyl-based synthon with deprotonated adipic acid produced a new coordination complex {[Zn(BIDPE)(hdc)]·2 H;O}n(1). The structure was characterized by single-crystal X-ray crystallography. It crystallizes in monoclinic, space group C2/m, at 293 K: a = 12.005(2), b = 17.956(3), c = 12.039(2) ?, β = 113.089(3)°, V = 2387.3(7) ?;, Z = 4, Dc = 1.524 g·cm-3, μ(Mo Ka) = 1.082 mm–1 and F(000) = 1136. 5942 reflections were measured and 2180 independent reflections(Rint = 0.0679) were used in further refinement. Complex 1 reveals 1D double-stranded chains containing [Zn;(BIDPE);] and [Zn;(hdc);] metallocyclic rings. The adjacent chains are linked by H-bonding and π···π interactions to form a 3D network. Thermal stability and luminescence property were studied. Interestingly, the luminescent emission of 1 can be quenched by the addition of trace amount of acetone, demonstrating its potential application for sensitive detecting acetone.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50872069 and 50872074)
文摘The acetone-sensing properties of the undoped and Pd doped perovskite-type oxides NdFeO3 were investigated from room temperature to 400°C. The perovskite-type NdFeO3 was synthesized by a sol-gel method, and the dopants Pd with the content from 1wt% to 5wt% were implanted into NdFeO3 nanoparticles by thermal diffusion. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques show that NdFeO3 is an orthorhombic structure with the average particle size of about 40 nm. A giant acetone-sensing response of 675.7 is observed when the Pd content in NdFeO3 powders is about 3wt%. The response and recovery time of the sensor to the 5×10–4 acetone gas are 16 and 1 s, respectively. At the same time, it performs a good selectivity to acetone gas and may be a new promising material candidate for the acetone-sensor development.
文摘Acetone diffusion in polycarbonate was investigated by spin-echo ~1H NMR imaging method at room temperature. The result shows that the diffusion process satisfies Case Ⅱ diffusion. The velocity of diffusion front is 13.8nm sec^(-1)(0.05mm/h).
基金Project(30916014103) supported by the Fundamental Research Funds for the Central Universities,China
文摘Ternary Au/Fe2O3-ZnO gas-sensing materials were synthesized by combining co-precipitation and microwave irradiation process.The as-prepared Au/Fe2O3-ZnO was characterized with X-ray diffractometer and scanning electron microscope,and its gas-sensing performance was measured using a gas-sensor analysis system.The results show that the as-prepared products consist of hexagonal wurtzite ZnO,face-centered cubic gold nanoparticles and orthorhombic Fe2O3crystallines.The Au/Fe2O3-ZnO based sensor has a very high selectivity to ethanol and acetone,and also has high sensitivity(154)at a low working temperature(270°C)and an extremely fast response(1s)against acetone.It is found that the selectivity can be adjusted by Fe2O3content added in the ternary materials.It possesses a worth looking forward prospect to practical applications in acetone detecting and administrating field.
基金supported by the National Natural Science Foundation of China(51672312,21373275)the Science and Technology Program of Wuhan,China(2016010101010018,2015070504020220)the Dean’s Research Fund–04257 from the Education University of Hong Kong~~
文摘TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.
文摘In recent years, clinical studies have found that acetone concentration in exhaled breath can be taken as a characteristic marker of diabetes. Metal-oxide-semiconductor (MOS) materials are widely used in acetone gas sensors due to their low cost, high sensitivity, fast response/recovery time, and easy integration. This paper reviews recent progress in acetone sensors based on MOS materials for diabetes diagnosis. The methods of improving the performance of acetone sensor have been explored for comparison, especially in high humidity conditions. We summarize the current excellent methods of preparations of sensors based on MOSs and hope to provide some help for the progress of acetone sensors in the diagnosis of diabetes.
文摘Acetone,which is volatile,flammable,toxic,expen- sive and causing serious air pollution,is often used as extracting solvent in the production of powdery soy phospholipid.Recycling and reusing acetone is the key of reducing the cost of production. Therefore,saving energy and reducing emission when recycling acetone are the most important technologies during the production of phospholipid.On the basis of the productivity of powdery phospholipid being 2.4 t every day,43.2 t acetone is reused every 8 h and the total volume of acetone gas emitted is 450.75 m3 (about 901.5 kg).According to the current price of acetone,the lost money is about 7212 yuan RMB.
基金supported by the National Natural Science Foundation of China (Nos. 51772130, 51972145)。
文摘The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.