可控电化学法合成超细金属氧化物粉体的研究

【作者】 徐秀梅；

【导师】 袁福龙；

【作者基本信息】 黑龙江大学 ， 无机化学， 2008， 硕士

【摘要】 本文采用两室（阴离子交换膜为隔膜）可控电化学的方法,研究了Zn²⁺、Al³⁺、La³⁺和Mg²⁺等四种不同金属离子制备其纳米金属氧化物的制备条件,着重讨论了金属离子的电极电势、电流密度、分散剂、焙烧温度等条件对其纳米金属氧化物的制备工艺的影响,利用TEM、TG-DTA、XRD和UV等测试手段对制备产物进行表征,并探索其纳米金属氧化物的制备机理。通过阴离子交换膜在两室可控电化学反应过程中起到有效的隔离作用,在阴极室可形成稳定的沉淀环境。利用控制阴极上的电流密度大小来控制沉淀离子生成的速度,进而可形成金属离子沉淀物晶核不同程度的过饱和度,在不加分散剂的情况下,可以形成获得颗粒均匀的纳米尺寸的金属氧化物的制备环境,实验证明电流密度大小对制备金属氧化物起到至关重要的作用。通过研究不同的溶液制备体系,能够有效地控制电解体系中的电解反应,可以避免具有不同氧化还原电势的金属离子在阴极上优先还原,实验证明选择合适的溶液制备纳米金属氧化物体系可达到目标化学反应的控制和实现。研究了可控电化学反应得到的其金属氢氧化物沉淀,在不同的温度下进行热解反应,可以得到结构、粒度均不同的金属氧化物粉体,并发现随着热解温度的升高,其氧化物的颗粒尺寸逐渐增加,晶型不断完善,因此,确定合适的热解温度是制备出纳米金属氧化物非常重要条件之一。更多还原

【Abstract】 The electrolyzing method in both chambers divided by anion-exchanging membrance is studied in the paper, analyzing preparation conditions of nanoscale oxides made of different ions of Zn²⁺, Al³⁺, La³⁺ and Mg²⁺, discussing the relations of the preparation conditions of ionic electrode potential, current density, disperser, calcining temperature to the influence of prepatation technology of nanoscale oxides. The nanoscale materials are characterized by using the methods of TEM,TG-DTA,XRD and UV. Its preparation mechanics is investigated in the paper.Anion-exchanging membrane is used as membrane to form the stable precipitation environment in process of controllably electrolyzing in the both chamber. The productive deposition speed is controlled by the electrolyzing speed to form certain extent supersaturation of crystal nucleus, which is more important for forming nanoscale oxides. The preparation environment of uniform and nanoscale oxides particles is obtained without adding disperser. The variant current density is vital to the preparation of nanoscale oxides.Electricity potential of oxidizing and deoxidizing of metal ions and the system of preparing solution are chosen fitly to avoid deoxidization of metal ions on cathode by controlling electrolytic reaction in the different solution system. The fact that the system of preparing solution which is used to make nanoscale oxides is seleced properly to realize the aiming reactions is confirmed by by the experiments.The predecessors of nanoscale oxides produced by the controllably electrolyzing deposition method can be made to form oxides of different sizes and crystal groups under different heat temperatures. With calcined temperatures rising, the size of oxide particles will be augmented and crystal group will be perfected, thus one of the most important factors of making nanoscale materials can’t be ignored by making sure of calcined temperatures.更多还原