Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while ...Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs （SEM） show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed.展开更多
A simple and efficient approach was presented to enhance up-conversion emissions significantly for the Er：Al2O3 nanocrystals by Mo support （Er-Mo：Al2O3） with a 976 nm laser diode excitation. Mo support had evident...A simple and efficient approach was presented to enhance up-conversion emissions significantly for the Er：Al2O3 nanocrystals by Mo support （Er-Mo：Al2O3） with a 976 nm laser diode excitation. Mo support had evident effects on the phase structure and up-conversion emissions for the Er：Al2O3 nanocrystals, which promoted the θ-（Al,Er）2O3 transformed to α-（Al,Er,Mo）203 phase, Compared with the Er：Al2O3, the maximal green and red up-conversion emissions intensities increased about 3×10^3 and 1.4×10^2 times for the Er-Mo：Al2O3 nanocrystals, respectively. It suggests that the enhancement of up-conversion emissions is caused by the high excited state energy transfer process from [4115/2, 3T2） state of the Er3＋-MoO2- dimer to the 4F7/2 level of E3＋.展开更多
基金M/s NALCO, Bhubaneswar for the partial financial support to carry out this work
文摘Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs （SEM） show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 11004021)the Fundamental Research Funds for the Central Universities (Grant Nos. DC12010117 and DC120101174)
文摘A simple and efficient approach was presented to enhance up-conversion emissions significantly for the Er：Al2O3 nanocrystals by Mo support （Er-Mo：Al2O3） with a 976 nm laser diode excitation. Mo support had evident effects on the phase structure and up-conversion emissions for the Er：Al2O3 nanocrystals, which promoted the θ-（Al,Er）2O3 transformed to α-（Al,Er,Mo）203 phase, Compared with the Er：Al2O3, the maximal green and red up-conversion emissions intensities increased about 3×10^3 and 1.4×10^2 times for the Er-Mo：Al2O3 nanocrystals, respectively. It suggests that the enhancement of up-conversion emissions is caused by the high excited state energy transfer process from [4115/2, 3T2） state of the Er3＋-MoO2- dimer to the 4F7/2 level of E3＋.
