用微乳液法制备了明胶复合的纳米Co Fe O体。将明胶和亚铁盐以及钴盐制成凝胶,使该凝胶状反应物在微乳液的胶束中反应,再被还原-化合-成核长大。用XRD、TEM、SEM、EDS、IR等测试表明:微粉为明胶包裹的球形纳米微球。生成的微粒处于明胶...用微乳液法制备了明胶复合的纳米Co Fe O体。将明胶和亚铁盐以及钴盐制成凝胶,使该凝胶状反应物在微乳液的胶束中反应,再被还原-化合-成核长大。用XRD、TEM、SEM、EDS、IR等测试表明:微粉为明胶包裹的球形纳米微球。生成的微粒处于明胶蛋白分子的包裹之中,单个微粒的粒径3 3～4 6nm,每个复合微球中约有3～22个Co Fe O体粒子组成,微球的平均粒径为10～100nm,Co-Fe-O体复合微粉的比饱和磁化强度σs=1 532kAm-1·g-1;矫顽力Hc=18 4kAm-1;剩磁σr=322 5Am-1·g-1。展开更多
Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been disc...Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg 0 could be oxidized by active oxygen atom on the surface of nano-Fe 2 O 3 as well as lattice oxygen in nano-Fe 2 O 3 . Among the factors that affect Hg 0 oxidation by nano-Fe 2 O 3 , bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower efficiency of Hg 0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg 0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N 2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.展开更多
Cs-promoted Mo-Bi-Co-Fe-Ce-O catalyst for the selective oxidation of isobutylene to methacrolein had been studied in a fixed bed micro-reactor. The selectivity to methacrolein was significantly improved by the additio...Cs-promoted Mo-Bi-Co-Fe-Ce-O catalyst for the selective oxidation of isobutylene to methacrolein had been studied in a fixed bed micro-reactor. The selectivity to methacrolein was significantly improved by the addition of Cs, which could probably enhance the dehydrogenation ability and weaken the oxygenation ability of the catalyst based on temperature programmed reduction （TPR） analysis investigation. The kinetic studies indicated that the oxidation of isobutylene to methacrolein followed the first-order kinetic behavior.展开更多
The 5-parameter Morse pntential（5-MP） of the interaction between oxygen atoms and iron surfaces was constructed. The adsorption and diffusion of O atoms on Fe low-index and Fe（211 ） high-index surfaces were invest...The 5-parameter Morse pntential（5-MP） of the interaction between oxygen atoms and iron surfaces was constructed. The adsorption and diffusion of O atoms on Fe low-index and Fe（211 ） high-index surfaces were investigated by using 5-MP. All the critical characteristics of the system, such as adsorption site, adsorption geometry, binding energy, and eigenvalues for vibration, were calculated. The calculation results show that O atoms are located at the fourfold hollow site of the Fe（100） surface with an eigenvibration at437 cm^-1. These results are in good agreement with the experimental and theoretical results obtained previously. With regard to the adsorption site of O-Fe（110） system, the authors of this study assume that the preferential adsorption state is the H3 site and not the LB site, which is not in agreement with the experimental inferences obtained earlier. However, on the Fe（ 111 ） and Fe（211 ） surfaces, O atoms predominantly occupy the quasi-3-fold site.展开更多
文摘用微乳液法制备了明胶复合的纳米Co Fe O体。将明胶和亚铁盐以及钴盐制成凝胶,使该凝胶状反应物在微乳液的胶束中反应,再被还原-化合-成核长大。用XRD、TEM、SEM、EDS、IR等测试表明:微粉为明胶包裹的球形纳米微球。生成的微粒处于明胶蛋白分子的包裹之中,单个微粒的粒径3 3～4 6nm,每个复合微球中约有3～22个Co Fe O体粒子组成,微球的平均粒径为10～100nm,Co-Fe-O体复合微粉的比饱和磁化强度σs=1 532kAm-1·g-1;矫顽力Hc=18 4kAm-1;剩磁σr=322 5Am-1·g-1。
基金supported by the Scientific Funds for Outstanding Young Scientists of China(No.50525619)the National Natural Science Foundation of China(No.51078163,50706014)the National High Technology Research and Development Program(863)of China(No.2006AA05Z304)
文摘Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg 0 could be oxidized by active oxygen atom on the surface of nano-Fe 2 O 3 as well as lattice oxygen in nano-Fe 2 O 3 . Among the factors that affect Hg 0 oxidation by nano-Fe 2 O 3 , bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower efficiency of Hg 0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg 0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N 2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.
基金国家自然科学基金，国家高技术研究发展计划(863计划)，the Open Foundation of State Key Laboratory of Heavy Oil Processing
文摘Cs-promoted Mo-Bi-Co-Fe-Ce-O catalyst for the selective oxidation of isobutylene to methacrolein had been studied in a fixed bed micro-reactor. The selectivity to methacrolein was significantly improved by the addition of Cs, which could probably enhance the dehydrogenation ability and weaken the oxygenation ability of the catalyst based on temperature programmed reduction （TPR） analysis investigation. The kinetic studies indicated that the oxidation of isobutylene to methacrolein followed the first-order kinetic behavior.
基金the Natural Science Foundation of Shandong Province(No Y2002B09)
文摘The 5-parameter Morse pntential（5-MP） of the interaction between oxygen atoms and iron surfaces was constructed. The adsorption and diffusion of O atoms on Fe low-index and Fe（211 ） high-index surfaces were investigated by using 5-MP. All the critical characteristics of the system, such as adsorption site, adsorption geometry, binding energy, and eigenvalues for vibration, were calculated. The calculation results show that O atoms are located at the fourfold hollow site of the Fe（100） surface with an eigenvibration at437 cm^-1. These results are in good agreement with the experimental and theoretical results obtained previously. With regard to the adsorption site of O-Fe（110） system, the authors of this study assume that the preferential adsorption state is the H3 site and not the LB site, which is not in agreement with the experimental inferences obtained earlier. However, on the Fe（ 111 ） and Fe（211 ） surfaces, O atoms predominantly occupy the quasi-3-fold site.
