New Insights into the Mechanism of ZnO Formation from Aqueous Solutions of Zinc Acetate and Zinc Nitrate
New Insights into the Mechanism of ZnO Formation from Aqueous Solutions of Zinc Acetate and Zinc Nitrate
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DOI：
10.1021/cm501096p
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发表时间：
2014-07-22
影响因子：
8.6
通讯作者：
Perry, Carole C.
中科院分区：
文献类型：
--
作者：
Liang, Mei-Keat;Limo, Marion J.;Perry, Carole C.
由于氧化锌在电学和光电子应用中的重要性，以及在晶体形成阶段调节其性质的潜力，在微米和纳米尺度上的可控合成一直是重要研究的重点。我们对氧化锌的生长过程进行了详细的研究，支持和巩固了以前的发现，并对氧化锌的形成机理有了更清晰的理解。通过比较两种不同的生长途径(锌(CH3COO)(2)-NH3和锌(NO3)(2)中心点6H(2)O-HMTA)，研究了合成条件对氧化锌形成的影响，这两种生长途径都可以形成纤锌矿结构的孪晶六角形氧化锌。通过扫描电子显微镜、X射线衍射仪、傅立叶变换红外光谱、X射线光电子能谱、热重分析和电感耦合等离子体发射光电子能谱分析的数据证实了形成的固相和上清液的一致性，揭示了多步反应途径的参与。在这两种情况下，反应都是通过称为层状碱性锌盐(LBZ)的中间体发生的，这些中间体后来才转化为氧化物相。在ZnAc_2-NH_3体系中，晶体的生长通过溶解/再沉淀过程演变为Zn(CH3COO)(2)->；LBZA(A：醋酸酯)->；ZnO，并形成一个额外的产物LBZAC(C：碳酸盐)。相反，在锌(硝酸盐)(2)中心点6H(2)O-HMTA体系中，固相转变为锌(硝酸盐)(2)中心点6H(2)O->；LBZN(N：硝酸盐)->；氧化锌，没有溶解迹象。类似的综合研究可以应用于其他固态工艺，以进一步推进功能材料的设计。
The controlled synthesis of ZnO at the micro- and nanoscale has been the focus of significant research due to its importance in electrical and optoelectronic applications, and the potential of tuning its properties at the crystal formation stage. We present a detailed study of ZnO growth processes which supports and consolidates previous findings and gives a clearer understanding of the mechanism of ZnO formation. The influence of synthesis conditions on ZnO formation was investigated by comparison of two different growth routes (Zn(CH3COO)(2)-NH3 and Zn(NO3)(2)center dot 6H(2)O-HMTA) both known to result in the formation of wurtzite structured, twinned hexagonal rods of ZnO. The identities of the solid phases formed and supernatants were confirmed by data from SEM, XRD, FTIR, XPS, TGA, and ICP-OES analysis; giving insight into the involvement of multistep pathways. In both cases, reaction takes place via intermediates known as layered basic zinc salts (LBZs) which only later transform to the oxide phase. In the ZnAc2-NH3 system, crystal growth evolves as Zn(CH3COO)(2) -> LBZA (A: acetate) -> ZnO through a dissolution/reprecipitation process, with the formation of an additional product identified as LBZAC (C: carbonate). In contrast, in the Zn(NO3)(2)center dot 6H(2)O-HMTA system, solid-phase transformation occurs as Zn(NO3)(2)center dot 6H(2)O -> LBZN (N: nitrate) -> ZnO with no evidence of dissolution. Similar comprehensive studies can be applied to other solid-state processes to further advance functional materials design.