Layered Double Hydroxides MgFe-LDH and MgAl-LDH have been prepared by th e method involving separate nucleation and ageing steps. The structure analyses for these two materials show that the values of the parameters b...Layered Double Hydroxides MgFe-LDH and MgAl-LDH have been prepared by th e method involving separate nucleation and ageing steps. The structure analyses for these two materials show that the values of the parameters both a and c of M gAl-LDH are smaller than that of MgFe-LDH though their structures are simila r, and MgAl-LDH with higher crystallinity is more easily formed than MgFe-LD H in the same preparing conditions. The IR analyses manifest that the structures of layer sheets and the orderings of the anions in the interlayer regions of Mg Al-LDH are more regular than that of MgFe-LDH. The temperature programmed XR D analyses reveal that the diffraction peak of 003 reflections for MgAl-LDH co uld be seen after calcining at 300℃, while this peak for MgFe-LDH disappears after calcining at 200℃. Together with the TG-DTA analysis it can be conclu ded that the thermal stability of MgAl-LDH is obviously higher than that of Mg Fe-LDH.展开更多
文摘Layered Double Hydroxides MgFe-LDH and MgAl-LDH have been prepared by th e method involving separate nucleation and ageing steps. The structure analyses for these two materials show that the values of the parameters both a and c of M gAl-LDH are smaller than that of MgFe-LDH though their structures are simila r, and MgAl-LDH with higher crystallinity is more easily formed than MgFe-LD H in the same preparing conditions. The IR analyses manifest that the structures of layer sheets and the orderings of the anions in the interlayer regions of Mg Al-LDH are more regular than that of MgFe-LDH. The temperature programmed XR D analyses reveal that the diffraction peak of 003 reflections for MgAl-LDH co uld be seen after calcining at 300℃, while this peak for MgFe-LDH disappears after calcining at 200℃. Together with the TG-DTA analysis it can be conclu ded that the thermal stability of MgAl-LDH is obviously higher than that of Mg Fe-LDH.
文摘为了得到高性能的双效氧电极,研究了钙钛矿型掺杂LaNiO3电催化剂的溶胶-凝胶制备方法,通过热重- 差热分析、红外分析、XRD分析以及催化剂的粒径分布分析等手段,探讨了pH值、柠檬酸用量以及焙烧制度对催化剂制备的影响.结果表明,制备LaNiO3的溶胶-凝胶法的最佳工艺条件是:柠檬酸的用量为金属离子总物质的量的1.5倍;pH值调节为9;焙烧制度为在750℃下焙烧2 h.
