Surface compositions,structures,and acidities of the Mo-Te-Fe-Ni catalysts added with La_2O_3,CeO_2, Pr_6O_(12),Nd_2O_3 and Sm_2O_3 were measured and related with the activities of the catalysts for selective oxidatio...Surface compositions,structures,and acidities of the Mo-Te-Fe-Ni catalysts added with La_2O_3,CeO_2, Pr_6O_(12),Nd_2O_3 and Sm_2O_3 were measured and related with the activities of the catalysts for selective oxidation of olefins.It was found that adding rare earth elements to the Mo-Te catalysts increases obviously their selectivities to methacrolein(MAL),and the yield percentage of MAL changes periodically with the increase of atomic numbers of rare earth elements added,and the highest yield was obtained with the catalyst containing CeO_2.The addition of CeO_2 to 9-component Mo-Te catalyst increases not only the activity of the catalyst, but also its thermostability remarkably.The mechanism of rare earth elements in the catalysts was discussed.展开更多
Polyheteroanions have a big volume and small electric charge density. They dissolve easily in water and organic solvents containing oxygen, and permeate readily through the cell membrane or protoplasm membrane. Thus t...Polyheteroanions have a big volume and small electric charge density. They dissolve easily in water and organic solvents containing oxygen, and permeate readily through the cell membrane or protoplasm membrane. Thus they may be absorbed by organisms easily. Two polyhetero-compounds, Na<sub>5</sub>FeW<sub>12</sub>O<sub>40</sub>XH<sub>2</sub>O (FeW<sub>12</sub>) and （NH<sub>4</sub>）<sub>3</sub>H<sub>6</sub>FeMo<sub>6</sub>XH<sub>2</sub>O（FeMo<sub>6</sub>）, were synthesized as food additives for layer-hen. The iron-complement effects, enrichment展开更多
文摘Surface compositions,structures,and acidities of the Mo-Te-Fe-Ni catalysts added with La_2O_3,CeO_2, Pr_6O_(12),Nd_2O_3 and Sm_2O_3 were measured and related with the activities of the catalysts for selective oxidation of olefins.It was found that adding rare earth elements to the Mo-Te catalysts increases obviously their selectivities to methacrolein(MAL),and the yield percentage of MAL changes periodically with the increase of atomic numbers of rare earth elements added,and the highest yield was obtained with the catalyst containing CeO_2.The addition of CeO_2 to 9-component Mo-Te catalyst increases not only the activity of the catalyst, but also its thermostability remarkably.The mechanism of rare earth elements in the catalysts was discussed.
文摘Polyheteroanions have a big volume and small electric charge density. They dissolve easily in water and organic solvents containing oxygen, and permeate readily through the cell membrane or protoplasm membrane. Thus they may be absorbed by organisms easily. Two polyhetero-compounds, Na<sub>5</sub>FeW<sub>12</sub>O<sub>40</sub>XH<sub>2</sub>O (FeW<sub>12</sub>) and （NH<sub>4</sub>）<sub>3</sub>H<sub>6</sub>FeMo<sub>6</sub>XH<sub>2</sub>O（FeMo<sub>6</sub>）, were synthesized as food additives for layer-hen. The iron-complement effects, enrichment
