采用溶胶-凝胶法制备的铁钴钡氧化物纳米颗粒作为非均相类芬顿催化剂,研究其催化降解亚甲基蓝,考察催化剂投加量,H_2O_2投加量,温度等对亚甲基蓝降解效率和降解速率的影响。结果表明,在最佳的实验条件下该氧化物颗粒与过氧化氢组成的芬...采用溶胶-凝胶法制备的铁钴钡氧化物纳米颗粒作为非均相类芬顿催化剂,研究其催化降解亚甲基蓝,考察催化剂投加量,H_2O_2投加量,温度等对亚甲基蓝降解效率和降解速率的影响。结果表明,在最佳的实验条件下该氧化物颗粒与过氧化氢组成的芬顿试剂在20 min内,亚甲基蓝降解率达到95%。该反应符合一级动力学模型,55℃条件下,速率常数为0.10 min^(-1),反应活化能为54.1 k J/mol。展开更多
采用固定床反应器,研究了Cu Cr Ca Ba催化剂上糠醛常压选择加氢制2 甲基呋喃的反应.详细考察了反应条件对催化性能的影响.结果表明,添加Ca Ba助剂显著提高了催化剂对目的产物的选择性,Cu Cr Ca Ba催化剂在200～220℃,液时空速0.2～0.6h...采用固定床反应器,研究了Cu Cr Ca Ba催化剂上糠醛常压选择加氢制2 甲基呋喃的反应.详细考察了反应条件对催化性能的影响.结果表明,添加Ca Ba助剂显著提高了催化剂对目的产物的选择性,Cu Cr Ca Ba催化剂在200～220℃,液时空速0.2～0.6h-1,氢醛摩尔比6～16的条件下,具有良好的活性和选择性,糠醛转化率 99.8%,2 甲基呋喃选择性 90.3%.展开更多
A precursor of BaCe 0.9 Nd 0.1 O 3-δ solid electrolyte was synthesized by the sol-gel method and sintered at14 00℃.The obtained gels and powder were characterized by differential and ther mogravimetric thermal analy...A precursor of BaCe 0.9 Nd 0.1 O 3-δ solid electrolyte was synthesized by the sol-gel method and sintered at14 00℃.The obtained gels and powder were characterized by differential and ther mogravimetric thermal analysis(TG-DTA),X-ray diffraction(XRD),transmissi on electron microscopy(TEM).Using the sintered samples as solid electrolyte a nd silver-palladium alloy as electrodes,electrical conductivities under differ ent gas ambiences at intermediate temperature(400～600℃)were measured. In moist hydrogen atmosphere,the conduction is a little higher than that of dry hydrogen atmosphere.In hydrogen atmosphere,proton conduction may predominate ,leading to an increase in conductivity and a decrease in activation energy.展开更多
In this paper, the nanometer permanent magnetic BaFe12O19 powder was synthesized by a novel method of independent nucleation and crystallization steps and subsequent heat treatment,during the synthesis, Ba(NO3)2, Fe(N...In this paper, the nanometer permanent magnetic BaFe12O19 powder was synthesized by a novel method of independent nucleation and crystallization steps and subsequent heat treatment,during the synthesis, Ba(NO3)2, Fe(NO3)2 and NH4HCO3·NH2COONH4 were used as starting materials. The effect of crystallization process and heat treatment conditions on the particle size, microstructure and magnetic properties of powder was studied by using XRD, TEM and vibration sample magnetometometer techniques.XRD results showed that the hematite, α Fe2O3, was the main phase in the powder at heat treatment temperatures below 650℃ and its amount in the powder was decreased with increasing temperature and small amount of α Fe2O3 was still remained after being heated at 900℃ for 8hrs. BaFe12O19 was formed about 650℃ and its amount increased in the powder as temperature raised and the higher temperature was needed to attain considerable amount of BaFe12O19 and ideal nanometer BaFe12O19 particle in the powder. The temperature between 40℃～60℃ in the crystallization process was favor to the formation of good BaFe12O19 crystal and to the good magnetic properties of the powder. TEM showed that the particle size in the powder increased with the enhancement of the temperature and the powder crystallized at 40℃ and heated at 800℃ for 8hrs afterwards had a very homogenous particle size distribution, and that the powder heated at 900℃ for 8hrs with the same crystalline condition as the former had a typical hexagonal shape and a chain aggregation. Specific saturation and residential magnetizations and coercive force of the powder increased monotonically with the increase of temperature, and reached 39.86A·m2·kg-1, 23.96A·m2·kg-1, 480kA·m-1 at 900℃, respectively.展开更多
BaxCe0.8Y0.2O3-α(x=1.03,1,0.98) solid electrolyte samples show a single phase of orthorhombic perovskite of BaCeO3. The oxide ion conduction and transport number were detected in the temperature of 600～1000℃by elec...BaxCe0.8Y0.2O3-α(x=1.03,1,0.98) solid electrolyte samples show a single phase of orthorhombic perovskite of BaCeO3. The oxide ion conduction and transport number were detected in the temperature of 600～1000℃by electrochemical oxygen permeation (oxygen pumping), and compared with the results from the oxygen concentration cell. The relation between the ingredient of Ba and oxide ion conduction was also researched. It was found that these electrolytes exhibited the mixed oxide ionic and electronic hole conduction under the experimental temperature and oxygen gas. The oxide ion transport numbers are 0.1～0.6, which are close to the results of the oxygen concentration cell. They increase as the decrease of Ba content in the samples.展开更多
The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The resu...The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.展开更多
文摘采用溶胶-凝胶法制备的铁钴钡氧化物纳米颗粒作为非均相类芬顿催化剂,研究其催化降解亚甲基蓝,考察催化剂投加量,H_2O_2投加量,温度等对亚甲基蓝降解效率和降解速率的影响。结果表明,在最佳的实验条件下该氧化物颗粒与过氧化氢组成的芬顿试剂在20 min内,亚甲基蓝降解率达到95%。该反应符合一级动力学模型,55℃条件下,速率常数为0.10 min^(-1),反应活化能为54.1 k J/mol。
文摘A precursor of BaCe 0.9 Nd 0.1 O 3-δ solid electrolyte was synthesized by the sol-gel method and sintered at14 00℃.The obtained gels and powder were characterized by differential and ther mogravimetric thermal analysis(TG-DTA),X-ray diffraction(XRD),transmissi on electron microscopy(TEM).Using the sintered samples as solid electrolyte a nd silver-palladium alloy as electrodes,electrical conductivities under differ ent gas ambiences at intermediate temperature(400～600℃)were measured. In moist hydrogen atmosphere,the conduction is a little higher than that of dry hydrogen atmosphere.In hydrogen atmosphere,proton conduction may predominate ,leading to an increase in conductivity and a decrease in activation energy.
文摘In this paper, the nanometer permanent magnetic BaFe12O19 powder was synthesized by a novel method of independent nucleation and crystallization steps and subsequent heat treatment,during the synthesis, Ba(NO3)2, Fe(NO3)2 and NH4HCO3·NH2COONH4 were used as starting materials. The effect of crystallization process and heat treatment conditions on the particle size, microstructure and magnetic properties of powder was studied by using XRD, TEM and vibration sample magnetometometer techniques.XRD results showed that the hematite, α Fe2O3, was the main phase in the powder at heat treatment temperatures below 650℃ and its amount in the powder was decreased with increasing temperature and small amount of α Fe2O3 was still remained after being heated at 900℃ for 8hrs. BaFe12O19 was formed about 650℃ and its amount increased in the powder as temperature raised and the higher temperature was needed to attain considerable amount of BaFe12O19 and ideal nanometer BaFe12O19 particle in the powder. The temperature between 40℃～60℃ in the crystallization process was favor to the formation of good BaFe12O19 crystal and to the good magnetic properties of the powder. TEM showed that the particle size in the powder increased with the enhancement of the temperature and the powder crystallized at 40℃ and heated at 800℃ for 8hrs afterwards had a very homogenous particle size distribution, and that the powder heated at 900℃ for 8hrs with the same crystalline condition as the former had a typical hexagonal shape and a chain aggregation. Specific saturation and residential magnetizations and coercive force of the powder increased monotonically with the increase of temperature, and reached 39.86A·m2·kg-1, 23.96A·m2·kg-1, 480kA·m-1 at 900℃, respectively.
文摘BaxCe0.8Y0.2O3-α(x=1.03,1,0.98) solid electrolyte samples show a single phase of orthorhombic perovskite of BaCeO3. The oxide ion conduction and transport number were detected in the temperature of 600～1000℃by electrochemical oxygen permeation (oxygen pumping), and compared with the results from the oxygen concentration cell. The relation between the ingredient of Ba and oxide ion conduction was also researched. It was found that these electrolytes exhibited the mixed oxide ionic and electronic hole conduction under the experimental temperature and oxygen gas. The oxide ion transport numbers are 0.1～0.6, which are close to the results of the oxygen concentration cell. They increase as the decrease of Ba content in the samples.
文摘The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.
