The single hot thermocouple technique （SHTT） and high temperature equilibrium technique were combined to investigate the phase diagram of the CaO-SiO2-5%MgO-20%AlzO3-TiO2 system. The 1300 ℃ to 1500 ℃ liquidus line...The single hot thermocouple technique （SHTT） and high temperature equilibrium technique were combined to investigate the phase diagram of the CaO-SiO2-5%MgO-20%AlzO3-TiO2 system. The 1300 ℃ to 1500 ℃ liquidus lines are calculated according to the thermodynamic equations based on the pseudo-melting temperatures measured by the single hot thermocouple technique. The phase equilibria relationships are experimentally determined at 1400 ℃ using the high temperature equilibria technique followed by X-ray fluorescence （XRF）, X-ray diffraction（XRD）, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX） analysis. The liquid phase（L）, melilite solid solution phase （（C2MSz,C2AS）ss）, diopside phase（CMS2） and perovskite phase （CaO·TiO2） are found. Coupled with the liquidus lines and equilibria results, the phase diagram is constructed for the specified region of the CaO-SiO2-5%MgO-20%Al2O3-TiO2 system.展开更多
A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the ...A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900°C. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500°C had an apparent rate constant equal to 0.0075 min 1, which is superior to the performance of a commercial photocatalyst Degussa P25 Kapp = 0.0045 min 1 and of unmodified TiO2 （TP0500） Kapp = 0.0022 min 1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone （HQ）, benzoquinone （BQ） and （4CC） 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato （Lycopersicon esculentum） whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished展开更多
An efficient toluene removal in air using a plasma photocatalytic system（PPS） not only needs favorable surface reactions over photocatalysts under the action of plasma,but also requires the photocatalysts to efficie...An efficient toluene removal in air using a plasma photocatalytic system（PPS） not only needs favorable surface reactions over photocatalysts under the action of plasma,but also requires the photocatalysts to efficiently absorb light emitted from the discharge for driving the photocatalytic reactions. We report here that the PPS constructed by integrating a black titania（B-TiO2）photocatalyst with a dielectric barrier discharge（DBD） can effectively remove toluene with above 70% CO2 selectivity and remarkably reduced the concentration of secondary pollutants of ozone and nitrogen oxides at a specific energy input of 1500 J·l-1,while exhibiting good stability. Photocatalyst characterizations suggest that the B-TiO2 provides a high concentration of oxygen vacancies for the surface oxidation of toluene in DBD,and efficiently absorbs ultraviolet–visible light emitted from the discharge to induce plasma photocatalytic oxidation of toluene. The presence of B-TiO2 in the plasma region also results in a high discharge efficiency,facilitating the generation of large numbers of reactive species and thus the oxidation of toluene towards CO2. The greatly enhanced performance of the PPS integrated with B-TiO2 in toluene removal offers a promising approach to efficiently remove refractory volatile organic compounds from air at low temperatures.展开更多
Hydrogen(H2)production from photocatalytic reforming of cellulose is a promising way for sustainable H2 to be generated.Herein,we report a systematic study of the photocatalytic reforming of cellulose over Pt/m-TiO2(i...Hydrogen(H2)production from photocatalytic reforming of cellulose is a promising way for sustainable H2 to be generated.Herein,we report a systematic study of the photocatalytic reforming of cellulose over Pt/m-TiO2(i.e.mixed TiO2,80%of anatase and 20%of rutile)catalysts in water.The optimum operation condition was established by studying the effect of Pt loading,catalyst concentration,cellulose concentration and reaction temperature on the gas production rate of H2(r(H2))and CO2(r(CO2)),suggesting an optimum operation condition at 40°C with 1.0 g·L^-1of cellulose and 0.75 g·L^-1of 0.16-Pt/m-TiO2 catalyst(with 0.16 wt%Pt loadting)to achieve a relatively sound photocatalytic performance with rH2=9.95μmol·h^-1.It is also shown that although the photoreforming of cellulose was operated at a relatively mild condition(i.e.with an UV-A lamp irradiation at40°C in the aqueous system),a low loading of Pt at^0.16 wt%on m-TiO2 could promote the H2 production effectively.Additionally,by comparing the reaction order expressed from both r(H2)(a1)and r(CO2)(a2)with respect to cellulose and water,the possible mechanism of H2 production was proposed.展开更多
A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic（PEC） oxidation system was established by o-phenanthroline-Fe（Ⅱ）（Fe（phen）3^2＋） spectrophotometr...A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic（PEC） oxidation system was established by o-phenanthroline-Fe（Ⅱ）（Fe（phen）3^2＋） spectrophotometry and using anion exchange membrane. Fe （phen）3^2＋ can be oxidized to o-phenanthroline-Fe（Ⅲ）（Fe（phen）3^3＋） by strong oxidization of hydroxyl radicals（·OH）. Then the cumulate concentration of hydroxyl radicals can be calculated through determining the change of the Fe（phen）3^3＋ absorbency at 509 nm. In addition, the research results showed the production rate of hydroxyl radicals was affected obviously by pH of solution, the cumulate concentration of hydroxyl radicals was the largest at nearby the initial pH 6.3 （isoelectric point）, and the change direction of pH after illumination tended to nearby isoelectric point.展开更多
基金Projects(51104039,51374059,51304042)supported by the National Natural Science Foundation of ChinaProject(L2013114)supported by Scientific Research Fund of Liaoning Provincial Education Department,China+1 种基金Project(2012221013)supported by Programs of Liaoning Province for Science and Technology Development,ChinaProject(N130602002)supported by the Fundamental Research Funds for the Central Universities China
文摘The single hot thermocouple technique （SHTT） and high temperature equilibrium technique were combined to investigate the phase diagram of the CaO-SiO2-5%MgO-20%AlzO3-TiO2 system. The 1300 ℃ to 1500 ℃ liquidus lines are calculated according to the thermodynamic equations based on the pseudo-melting temperatures measured by the single hot thermocouple technique. The phase equilibria relationships are experimentally determined at 1400 ℃ using the high temperature equilibria technique followed by X-ray fluorescence （XRF）, X-ray diffraction（XRD）, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX） analysis. The liquid phase（L）, melilite solid solution phase （（C2MSz,C2AS）ss）, diopside phase（CMS2） and perovskite phase （CaO·TiO2） are found. Coupled with the liquidus lines and equilibria results, the phase diagram is constructed for the specified region of the CaO-SiO2-5%MgO-20%Al2O3-TiO2 system.
文摘A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900°C. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500°C had an apparent rate constant equal to 0.0075 min 1, which is superior to the performance of a commercial photocatalyst Degussa P25 Kapp = 0.0045 min 1 and of unmodified TiO2 （TP0500） Kapp = 0.0022 min 1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone （HQ）, benzoquinone （BQ） and （4CC） 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato （Lycopersicon esculentum） whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished
基金supported by National Natural Science Foundation of China (No. 21808024)Fundamental Research Funds for the Central Universities (DMU 3132018175)
文摘An efficient toluene removal in air using a plasma photocatalytic system（PPS） not only needs favorable surface reactions over photocatalysts under the action of plasma,but also requires the photocatalysts to efficiently absorb light emitted from the discharge for driving the photocatalytic reactions. We report here that the PPS constructed by integrating a black titania（B-TiO2）photocatalyst with a dielectric barrier discharge（DBD） can effectively remove toluene with above 70% CO2 selectivity and remarkably reduced the concentration of secondary pollutants of ozone and nitrogen oxides at a specific energy input of 1500 J·l-1,while exhibiting good stability. Photocatalyst characterizations suggest that the B-TiO2 provides a high concentration of oxygen vacancies for the surface oxidation of toluene in DBD,and efficiently absorbs ultraviolet–visible light emitted from the discharge to induce plasma photocatalytic oxidation of toluene. The presence of B-TiO2 in the plasma region also results in a high discharge efficiency,facilitating the generation of large numbers of reactive species and thus the oxidation of toluene towards CO2. The greatly enhanced performance of the PPS integrated with B-TiO2 in toluene removal offers a promising approach to efficiently remove refractory volatile organic compounds from air at low temperatures.
基金the China Scholarship Council(CSC,file no.201706950035)University of Manchester joint studentship for supporting her PhD researchthe CSC for her academic visiting fellowship at The University of Manchester(file no.201708440477)the Foundation of Department of Education of Guangdong Province(No.2017KZDXM085,2018KZDXM070)。
文摘Hydrogen(H2)production from photocatalytic reforming of cellulose is a promising way for sustainable H2 to be generated.Herein,we report a systematic study of the photocatalytic reforming of cellulose over Pt/m-TiO2(i.e.mixed TiO2,80%of anatase and 20%of rutile)catalysts in water.The optimum operation condition was established by studying the effect of Pt loading,catalyst concentration,cellulose concentration and reaction temperature on the gas production rate of H2(r(H2))and CO2(r(CO2)),suggesting an optimum operation condition at 40°C with 1.0 g·L^-1of cellulose and 0.75 g·L^-1of 0.16-Pt/m-TiO2 catalyst(with 0.16 wt%Pt loadting)to achieve a relatively sound photocatalytic performance with rH2=9.95μmol·h^-1.It is also shown that although the photoreforming of cellulose was operated at a relatively mild condition(i.e.with an UV-A lamp irradiation at40°C in the aqueous system),a low loading of Pt at^0.16 wt%on m-TiO2 could promote the H2 production effectively.Additionally,by comparing the reaction order expressed from both r(H2)(a1)and r(CO2)(a2)with respect to cellulose and water,the possible mechanism of H2 production was proposed.
文摘A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic（PEC） oxidation system was established by o-phenanthroline-Fe（Ⅱ）（Fe（phen）3^2＋） spectrophotometry and using anion exchange membrane. Fe （phen）3^2＋ can be oxidized to o-phenanthroline-Fe（Ⅲ）（Fe（phen）3^3＋） by strong oxidization of hydroxyl radicals（·OH）. Then the cumulate concentration of hydroxyl radicals can be calculated through determining the change of the Fe（phen）3^3＋ absorbency at 509 nm. In addition, the research results showed the production rate of hydroxyl radicals was affected obviously by pH of solution, the cumulate concentration of hydroxyl radicals was the largest at nearby the initial pH 6.3 （isoelectric point）, and the change direction of pH after illumination tended to nearby isoelectric point.
