Herein,we report a unique approach towards the preparation of C-modified and N-doped TiO2 hollow spheres(C/N-TiO2).TEM,SEM,and XPS analyses were used to confirm that the carbon and nitrogen co-decorated TiO2 photocata...Herein,we report a unique approach towards the preparation of C-modified and N-doped TiO2 hollow spheres(C/N-TiO2).TEM,SEM,and XPS analyses were used to confirm that the carbon and nitrogen co-decorated TiO2 photocatalyst was formed.Carbon-decoration improves the visible-light absorption and speeds up the separation of the photo-generated electron-hole pairs.C/N-TiO2 not only narrows the band gap of TiO2,but also exhibits excellent photocatalytic activity for the degradation of tetracycline and tetracycline hydrochloride.In addition,the C/N-TiO2 photocatalyst shows excellent recyclability for water decontamination,making it a promising candidate to purify aquatic contaminants.展开更多
Pd/LaxPbyMnOz, Pd/C, Pd/molecular sieve and Pd-heteropoly acid catalysts for direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction were compared and the results of DPC synthesis indicated th...Pd/LaxPbyMnOz, Pd/C, Pd/molecular sieve and Pd-heteropoly acid catalysts for direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction were compared and the results of DPC synthesis indicated that the catalyst Pd/LaxPbyMnOz had higher activity. The Pd/LaxPbyMnOz catalyst and the support was characterized by XRD, SEM and TEM, the main phase was Lao.szPbo.asMnOa and the average diameter could be about 25.4nm. The optimuna conditions for synthesis of DPC with Pd/LasPbyMnOz were determined by orthogonal experiments and the experimental results showed that reaction temperature was the first factor of effect on the selectivity and yield of DPC, and the concentration of O2 in gas phase also had significant effect on selectivity of DPC. The optimum reaction conditions were catalyst/phenol mass ratio l to 50, pressure 4.5MPa, volume concentration of O2 25%, reaction temperature 60℃ and reaction time 4 h. The maximum yield and average selectivity could reach 13% and 97% respectively in the batch operation.展开更多
This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized b...This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction （XRD）, Ultraviolet-Visible Diffuse Reflection Spectroscopy （UV-Vis DRS）, X-ray Photoelectron Spectroscopy （XPS）, Scanning Electron Microscopy （SEM）, Energy Dispersive Spectrometry （EDS）, Fourier Transform Infrared Spectroscopic Studies （FT-IR）, and Transmission Electron Microscopy （TEM）. From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV-Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region （red shift）, the entry ofCu2 ＋ into Ti02 lattice as a substitution- al dopant and S042- ions were covalently bonded with Ti4＋ on the surface of the copper doped titania respectively. The photocatalytic activity studies were investigated by considering methyl orange （MO） as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, pH of the solution, and concentration of the dye was studied in detail.展开更多
Granite is one of the most important components of the continental crust on our Earth; it thus has been an enduring studied subject in geology. According to present knowledge, granite shows a great deal of heterogenei...Granite is one of the most important components of the continental crust on our Earth; it thus has been an enduring studied subject in geology. According to present knowledge, granite shows a great deal of heterogeneity in terms of its texture,structure, mineral species and geochemical compositions at different scales from small dike to large batholith. However, the reasons for these variations are not well understood although numerous interpretations have been proposed. The key point of this debate is whether granitic magma can be effectively differentiated through fractional crystallization, and, if so, what kind of crystallization occurred during the magmatic evolution. Although granitic magma has high viscosity because of its elevated SiO2 content, we agree that fractional crystallization is effectively processed during its evolution based on the evidence from field investigation,mineral species and its chemical variations, and geochemical compositions. These data indicate that crystal settling by gravitation is not the only mechanism dominating granitic differentiation. On the contrary, flow segregation or dynamic sorting may be more important. Accordingly, granite can be divided into unfractionated, fractionated(including weakly fractionated and highly fractionated) and cumulated types, according to the differentiation degree. Highly fractionated granitic magmas are generally high in primary temperature or high with various volatiles during the later stage, which make the fractional crystallization much easier than the common granitic melts. In addition, effective magmatic differentiation can be also expected when the magma emplaced along a large scale of extensional structure. Highly fractionated granitic magma is easily contaminated by country rocks due to its relatively prolonged crystallization time. Thus, granites do not always reflect the characteristics of the source areas and the physical and chemical conditions of the primary magma. We proposed that highly fractionated granites are an important sign indicating compositional maturity of the continental crust, and they are also closely related to the rare-elemental(metal) mineralization of W,Sn, Nb, Ta, Li, Be, Rb, Cs, REEs, etc.展开更多
基金supported by the National Natural Science Foundation of China(21876069,21707054)the Six Talent Peaks Project in Jiangsu(XCL-018)the China Postdoctoral Science Foundation(2016M601744)~~
文摘Herein,we report a unique approach towards the preparation of C-modified and N-doped TiO2 hollow spheres(C/N-TiO2).TEM,SEM,and XPS analyses were used to confirm that the carbon and nitrogen co-decorated TiO2 photocatalyst was formed.Carbon-decoration improves the visible-light absorption and speeds up the separation of the photo-generated electron-hole pairs.C/N-TiO2 not only narrows the band gap of TiO2,but also exhibits excellent photocatalytic activity for the degradation of tetracycline and tetracycline hydrochloride.In addition,the C/N-TiO2 photocatalyst shows excellent recyclability for water decontamination,making it a promising candidate to purify aquatic contaminants.
基金National Natural Science Foundation of China(No.20076036Tianjin University C1 National Laboratory Project
文摘Pd/LaxPbyMnOz, Pd/C, Pd/molecular sieve and Pd-heteropoly acid catalysts for direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction were compared and the results of DPC synthesis indicated that the catalyst Pd/LaxPbyMnOz had higher activity. The Pd/LaxPbyMnOz catalyst and the support was characterized by XRD, SEM and TEM, the main phase was Lao.szPbo.asMnOa and the average diameter could be about 25.4nm. The optimuna conditions for synthesis of DPC with Pd/LasPbyMnOz were determined by orthogonal experiments and the experimental results showed that reaction temperature was the first factor of effect on the selectivity and yield of DPC, and the concentration of O2 in gas phase also had significant effect on selectivity of DPC. The optimum reaction conditions were catalyst/phenol mass ratio l to 50, pressure 4.5MPa, volume concentration of O2 25%, reaction temperature 60℃ and reaction time 4 h. The maximum yield and average selectivity could reach 13% and 97% respectively in the batch operation.
文摘This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction （XRD）, Ultraviolet-Visible Diffuse Reflection Spectroscopy （UV-Vis DRS）, X-ray Photoelectron Spectroscopy （XPS）, Scanning Electron Microscopy （SEM）, Energy Dispersive Spectrometry （EDS）, Fourier Transform Infrared Spectroscopic Studies （FT-IR）, and Transmission Electron Microscopy （TEM）. From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV-Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region （red shift）, the entry ofCu2 ＋ into Ti02 lattice as a substitution- al dopant and S042- ions were covalently bonded with Ti4＋ on the surface of the copper doped titania respectively. The photocatalytic activity studies were investigated by considering methyl orange （MO） as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, pH of the solution, and concentration of the dye was studied in detail.
基金supported by the National Natural Science Foundation of China (Grant No. 41130313)by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB03010200)
文摘Granite is one of the most important components of the continental crust on our Earth; it thus has been an enduring studied subject in geology. According to present knowledge, granite shows a great deal of heterogeneity in terms of its texture,structure, mineral species and geochemical compositions at different scales from small dike to large batholith. However, the reasons for these variations are not well understood although numerous interpretations have been proposed. The key point of this debate is whether granitic magma can be effectively differentiated through fractional crystallization, and, if so, what kind of crystallization occurred during the magmatic evolution. Although granitic magma has high viscosity because of its elevated SiO2 content, we agree that fractional crystallization is effectively processed during its evolution based on the evidence from field investigation,mineral species and its chemical variations, and geochemical compositions. These data indicate that crystal settling by gravitation is not the only mechanism dominating granitic differentiation. On the contrary, flow segregation or dynamic sorting may be more important. Accordingly, granite can be divided into unfractionated, fractionated(including weakly fractionated and highly fractionated) and cumulated types, according to the differentiation degree. Highly fractionated granitic magmas are generally high in primary temperature or high with various volatiles during the later stage, which make the fractional crystallization much easier than the common granitic melts. In addition, effective magmatic differentiation can be also expected when the magma emplaced along a large scale of extensional structure. Highly fractionated granitic magma is easily contaminated by country rocks due to its relatively prolonged crystallization time. Thus, granites do not always reflect the characteristics of the source areas and the physical and chemical conditions of the primary magma. We proposed that highly fractionated granites are an important sign indicating compositional maturity of the continental crust, and they are also closely related to the rare-elemental(metal) mineralization of W,Sn, Nb, Ta, Li, Be, Rb, Cs, REEs, etc.
