The effect of Lanthanum content,calcinating temperature and calcinating time on the photocatalytic activity of Lanthanum doping TiO 2 was investigated.The study showed that samples treated under higher temperature and...The effect of Lanthanum content,calcinating temperature and calcinating time on the photocatalytic activity of Lanthanum doping TiO 2 was investigated.The study showed that samples treated under higher temperature and longer calcinating time exhibited higher photocatalytic activity.The X ray diffraction pattern revealed that the lattice of those samples was highly expanded.It is suggested that the highly distorted crystal lattice may be involved in producing more ways by which the hole was captured.Thus,the photocatalytic activity of samples treated under higher temperature and longer time was promoted.展开更多
The iron doping titanium dioxide was prepared by sol-gel,step precipitation,co-precipitation and immersion methods,respectively.The photocatalytic activities of these prepared samples were evaluated in X-3B dispersion...The iron doping titanium dioxide was prepared by sol-gel,step precipitation,co-precipitation and immersion methods,respectively.The photocatalytic activities of these prepared samples were evaluated in X-3B dispersion irradiated under UV.The experimental results showed that the immersion method,especially using the nano TiO2 as immersion matrix,greatly enhanced the photocatalytic activity.One fold enhancement in photocatalytic activity was observed in the case of the sample prepared by immersion doping method.This may be attributed to the nano-size effect,the irreversible hole trapper in non-saturated bonding field of Fe3＋ and larger lattice strain.展开更多
Using Fe doped titania powders as the precursor, Fe doped TiO2 nanotubes with small diameter of 10nm were obtained by hydrothermal method. The doped titania powders have two different crystalline phases, anatase and r...Using Fe doped titania powders as the precursor, Fe doped TiO2 nanotubes with small diameter of 10nm were obtained by hydrothermal method. The doped titania powders have two different crystalline phases, anatase and rutile of which the average particle diameters are 30.3nm and 41.7nm, receptively. The products were characterized by TEM, XRD and EDS. The results showed that Fe doped TiO2 nanotubes of 200nm in length could be obtained from Fe doped rutile powder, and have higher yields. The formation mechanism of long titania nanotubes was suggested in the light of the relative stability of crystalline phase.展开更多
合成了表面包覆 Si O2 的超细 Ca CO3 。通过 XPS,XRD对包覆表面层结构的分析 ,证实了 Si O2 以无定形包覆于 Ca CO3 表面 ,并在其表面形成了 Si- O- Ca键。对 Si O2 包覆超细 Ca CO3 的机理分析结果可知 :Na2 Si O3 的加入量是影响包...合成了表面包覆 Si O2 的超细 Ca CO3 。通过 XPS,XRD对包覆表面层结构的分析 ,证实了 Si O2 以无定形包覆于 Ca CO3 表面 ,并在其表面形成了 Si- O- Ca键。对 Si O2 包覆超细 Ca CO3 的机理分析结果可知 :Na2 Si O3 的加入量是影响包覆效率的重要因素 ,由于硅酸易自聚 ,控制 Si O2 与 Ca CO3 的重量比约为4 %～ 5 %时为包覆的最佳点 ;Ca CO3 晶粒度大小影响分散性能 ,进而影响包覆效率 ,分散性能好的包覆效率较高。展开更多
Spherical calcium carbonate was prepared by the reaction of sodium carbonate with calcium chloride at the presence of a protein like molecule, polyvinylpyrrolidone, as the template. The products were characterized by ...Spherical calcium carbonate was prepared by the reaction of sodium carbonate with calcium chloride at the presence of a protein like molecule, polyvinylpyrrolidone, as the template. The products were characterized by elemental analyses, XRD, SEM, and TG DSC respectively. The effects of polyvinylpyrrolidone on the crystal form and morphology of the as prepared CaCO3 were investigated. It was found that the aggregative shape of the produced calcium carbonate crystalline could be well controlled by adjusting the concentration of the polyvinylpyrrolidone template. This may be of important meanings to the biomimetic synthesis of novel inorganic materials.展开更多
Shape apprearance and crystallite characterization of magnesium hydroxide at different hydrothermal temperatures have been investigated by SEM, XRD and DSC methods. The grain size, cell parameter and lattice distortio...Shape apprearance and crystallite characterization of magnesium hydroxide at different hydrothermal temperatures have been investigated by SEM, XRD and DSC methods. The grain size, cell parameter and lattice distortion rate of powders under each condition were obtained. The results show that the grains had grown up, especially along the (001) surface as the hydrothermal temperature was raised, accompanying the shrinkage of lattice and the descending of distortion rate. These could be relate to the re crystallization of Mg(OH)2, as well as the thermal diffusion of OH-with lower charges, resulting in good dispersion, high thermal decomposition temperature and enthalpy of Mg(OH)2. Moreover, it is helpful for the increase of the retardant behavior of Mg(OH)2.展开更多
The spherical CaCO3 composite was synthesized in the presence of the amphiphilic block copolymer, i.e. polystyrene-b-poly(acrylic acid). It was revealed by XRD analysis that the grains in the composite was calcite wit...The spherical CaCO3 composite was synthesized in the presence of the amphiphilic block copolymer, i.e. polystyrene-b-poly(acrylic acid). It was revealed by XRD analysis that the grains in the composite was calcite with great distortion. Infared and Raman analysis showed that the composite was composed of PS-b-PAA calcium salt and calcite, and the calcite was nano-scaled.展开更多
文摘The effect of Lanthanum content,calcinating temperature and calcinating time on the photocatalytic activity of Lanthanum doping TiO 2 was investigated.The study showed that samples treated under higher temperature and longer calcinating time exhibited higher photocatalytic activity.The X ray diffraction pattern revealed that the lattice of those samples was highly expanded.It is suggested that the highly distorted crystal lattice may be involved in producing more ways by which the hole was captured.Thus,the photocatalytic activity of samples treated under higher temperature and longer time was promoted.
文摘The iron doping titanium dioxide was prepared by sol-gel,step precipitation,co-precipitation and immersion methods,respectively.The photocatalytic activities of these prepared samples were evaluated in X-3B dispersion irradiated under UV.The experimental results showed that the immersion method,especially using the nano TiO2 as immersion matrix,greatly enhanced the photocatalytic activity.One fold enhancement in photocatalytic activity was observed in the case of the sample prepared by immersion doping method.This may be attributed to the nano-size effect,the irreversible hole trapper in non-saturated bonding field of Fe3＋ and larger lattice strain.
文摘Using Fe doped titania powders as the precursor, Fe doped TiO2 nanotubes with small diameter of 10nm were obtained by hydrothermal method. The doped titania powders have two different crystalline phases, anatase and rutile of which the average particle diameters are 30.3nm and 41.7nm, receptively. The products were characterized by TEM, XRD and EDS. The results showed that Fe doped TiO2 nanotubes of 200nm in length could be obtained from Fe doped rutile powder, and have higher yields. The formation mechanism of long titania nanotubes was suggested in the light of the relative stability of crystalline phase.
文摘合成了表面包覆 Si O2 的超细 Ca CO3 。通过 XPS,XRD对包覆表面层结构的分析 ,证实了 Si O2 以无定形包覆于 Ca CO3 表面 ,并在其表面形成了 Si- O- Ca键。对 Si O2 包覆超细 Ca CO3 的机理分析结果可知 :Na2 Si O3 的加入量是影响包覆效率的重要因素 ,由于硅酸易自聚 ,控制 Si O2 与 Ca CO3 的重量比约为4 %～ 5 %时为包覆的最佳点 ;Ca CO3 晶粒度大小影响分散性能 ,进而影响包覆效率 ,分散性能好的包覆效率较高。
文摘Spherical calcium carbonate was prepared by the reaction of sodium carbonate with calcium chloride at the presence of a protein like molecule, polyvinylpyrrolidone, as the template. The products were characterized by elemental analyses, XRD, SEM, and TG DSC respectively. The effects of polyvinylpyrrolidone on the crystal form and morphology of the as prepared CaCO3 were investigated. It was found that the aggregative shape of the produced calcium carbonate crystalline could be well controlled by adjusting the concentration of the polyvinylpyrrolidone template. This may be of important meanings to the biomimetic synthesis of novel inorganic materials.
文摘Shape apprearance and crystallite characterization of magnesium hydroxide at different hydrothermal temperatures have been investigated by SEM, XRD and DSC methods. The grain size, cell parameter and lattice distortion rate of powders under each condition were obtained. The results show that the grains had grown up, especially along the (001) surface as the hydrothermal temperature was raised, accompanying the shrinkage of lattice and the descending of distortion rate. These could be relate to the re crystallization of Mg(OH)2, as well as the thermal diffusion of OH-with lower charges, resulting in good dispersion, high thermal decomposition temperature and enthalpy of Mg(OH)2. Moreover, it is helpful for the increase of the retardant behavior of Mg(OH)2.
文摘The spherical CaCO3 composite was synthesized in the presence of the amphiphilic block copolymer, i.e. polystyrene-b-poly(acrylic acid). It was revealed by XRD analysis that the grains in the composite was calcite with great distortion. Infared and Raman analysis showed that the composite was composed of PS-b-PAA calcium salt and calcite, and the calcite was nano-scaled.
