Pure, layered compounds of overlithiated Li1＋xNi0.8Co0.2O2（x = 0.05 and 0.1） were successfully prepared by a modified combustion method. XRD studies showed that cell parameters of the material decreased with increa...Pure, layered compounds of overlithiated Li1＋xNi0.8Co0.2O2（x = 0.05 and 0.1） were successfully prepared by a modified combustion method. XRD studies showed that cell parameters of the material decreased with increasing the lithium content. SEM revealed that the morphology of particles changed from rounded polyhedral-like crystallites to sharp-edged polyhedral crystals with more doped lithium. EDX showed that the stoichiometries of Ni and Co agrees with calculated synthesized values. Electrochemical studies revealed the overlithiated samples have improved capacities as well as cycling behavior. The sample with x = 0.05 shows the best performance with a specific capacity of 113.29 mA.h.g-1 and the best capacity retention of 92.2% over 10 cycles. XPS results showed that the binding energy of Li ls is decreased for the Li doped samples with the smallest value for the x = 0.05 sample, implying that Li＋ ions can be extracted more easily from Li1.05Ni0.8Co0.2O2 than the other stoichiometries accounting for the improved performance of the material. Considerations of core level XPS peaks for transition metals reveal the existence in several oxidation states. However, the percentage of the＋3 oxidation state of transition metals for the when x = 0.1 is the highest and the availability for charge transition from the ＋3 to＋4 state of the transition metal during deintercalation is more readily available.展开更多
We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2（fum）2（bpy）] and [Zn4 O（bdc）3]（fum = fumaric acid; bpy =4,4-bipyridine; bdc = benzene-1,4-dicarboxylate...We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2（fum）2（bpy）] and [Zn4 O（bdc）3]（fum = fumaric acid; bpy =4,4-bipyridine; bdc = benzene-1,4-dicarboxylate） metal–organic frameworks（MOFs） as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared（FT-IR） spectroscopy, and powder X-ray diffraction（PXRD）. Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R2 values of 0.973 and0.993 obtained for [Zn2（fum）2（bpy）] and [Zn4 O（bdc）3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62 mg/g on the[Zn2（fum）2（bpy）] and [Zn4 O（bdc）3] MOFs respectively, and were obtained at p H of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.展开更多
文摘Pure, layered compounds of overlithiated Li1＋xNi0.8Co0.2O2（x = 0.05 and 0.1） were successfully prepared by a modified combustion method. XRD studies showed that cell parameters of the material decreased with increasing the lithium content. SEM revealed that the morphology of particles changed from rounded polyhedral-like crystallites to sharp-edged polyhedral crystals with more doped lithium. EDX showed that the stoichiometries of Ni and Co agrees with calculated synthesized values. Electrochemical studies revealed the overlithiated samples have improved capacities as well as cycling behavior. The sample with x = 0.05 shows the best performance with a specific capacity of 113.29 mA.h.g-1 and the best capacity retention of 92.2% over 10 cycles. XPS results showed that the binding energy of Li ls is decreased for the Li doped samples with the smallest value for the x = 0.05 sample, implying that Li＋ ions can be extracted more easily from Li1.05Ni0.8Co0.2O2 than the other stoichiometries accounting for the improved performance of the material. Considerations of core level XPS peaks for transition metals reveal the existence in several oxidation states. However, the percentage of the＋3 oxidation state of transition metals for the when x = 0.1 is the highest and the availability for charge transition from the ＋3 to＋4 state of the transition metal during deintercalation is more readily available.
基金Royal Society of Chemistry for the award of 2016 Royal Society of Chemistry (RSC) Research Fund Grant
文摘We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2（fum）2（bpy）] and [Zn4 O（bdc）3]（fum = fumaric acid; bpy =4,4-bipyridine; bdc = benzene-1,4-dicarboxylate） metal–organic frameworks（MOFs） as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared（FT-IR） spectroscopy, and powder X-ray diffraction（PXRD）. Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R2 values of 0.973 and0.993 obtained for [Zn2（fum）2（bpy）] and [Zn4 O（bdc）3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62 mg/g on the[Zn2（fum）2（bpy）] and [Zn4 O（bdc）3] MOFs respectively, and were obtained at p H of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.
