两级反应器制备Zn^(2+)原位掺杂型LDHs纳米晶

Synthesis of Zn^(2+) In-Situ Doped LDHs Nanocrystal by the Two-Stage Reactor

采用两级反应器,将盐溶液MgCl2.6H2O、AlCl3.6H2O、ZnCl2.6H2O和沉降剂Na2CO3、NaOH进行反应成功制备出Zn2+原位掺杂型LDHs纳米晶。采用XRD、TEM、TG分析了Zn2+掺杂对MgAl-CO3LDHs晶体结构、形貌与热稳定性的影响。结果表明:当[Mg2++Zn2+]/[Al3+]=2,[Mg2+]/[Zn2+]=4时,对MgAl-CO3LDHs晶体结构影响最小,此时晶体形貌也相对较规则;原位掺杂后,95℃晶化2 h为最佳晶化时间;Zn2+掺杂LDHs纳米晶在0～450℃范围内热稳定性降低,在450～550℃范围内热稳定性提高,且残渣量由46.57%提高到58.58%。

Zn2 ＋ in-situ doped nano-LDHs material was prepared in the two-stage reactor by reaction of the salt solution of MgCl2.6H2O,AlCl3.6H2O,ZnCl2.6H2O,and the alkali solution of Na2CO3,NaOH.XRD,TEM,TG were employed to analyze effect of doped Zn2 ＋ on crystal structure,morphology and thermal stability of MgAl-CO3LDHs.The results show that the ratio of [Mg2 ＋ ＋ Zn2 ＋]/[Al3 ＋] equals to 2,and [Mg2 ＋]/[Zn2 ＋]equals to 4 is optimum condition to the crystal structure and crystal morphology;After in-situ doping,the crystallization time of two hours is desirable one for crystal to achieve high crystallinity and regular structure;The thermal stability of doped LDHs was lower than none doped LDHs between 0 ℃ and 450 ℃,but higher than none doped LDHs between 450 ℃ and 550 ℃,moreover,the residue of the decomposition was increased from 46.57% to 58.58%.