金属离子诱导新方法合成高能面暴露的金属氧化物纳米材料及性能研究

High-index facets usually have higher surface energy and more adatoms, vacancies and kinks, which makes the high-index facets have better activities in photo- and electro-catalysis and have special applications in optical, electrical, sonic, and magnetic devices. However, during the crystal growth, high-index facets usually have fast growth rates due to the high surface energy and ultimately disappear. So, it is a big challenge for scientists to synthesize nanocrystals bound by high-index facets. The species in the growth environment would play important roles, which makes introducing impurities or additive in the solution be an effective way to tailor the shape of crystals since impurity/additive would possibly interact with faces with some atomic configurations to change surface relative stability in terms of surface energy. The most used additives are halogen ions,surfactant and there are few reports about the metal ions in controlling the size and shape of nanostructures. Iron oxide, manganese oxide and cuprous oxide et al, have potential applications in many fields, as the target metal oxide nanomaterials, with metal ions as structure-directing agents,at certain coordination agents (such as ammonia or ethylene diamine, etc.) existing conditions, through the precipitation, hydrothermal method, solvothermal method, liquid phase methods controlled synthesize high-index faced metal oxide nanocrystals, explore the effect mechanism of the metal ions in the high-index faced nanocrystals synthesis. And study the high-index faced metal oxides properties such as electric catalysis, photocatalysis, gas sensitivities, research the relationship between exposed suface and properties and construct the superior performance of catalysis, sensing of nanomaterials.

高能面具有更高的反应活性，更多的空位，可以应用于光、电、声、磁等领域。然而高能面在晶体生长过程中很容易消失，因此合成高能面暴露的纳米晶是一个很大的挑战。在反应体系中引入一些添加剂，对纳米晶的表面控制起到很大的作用，合成高能面常用的添加剂为卤素离子和表面活性剂，关于金属离子控制的报道很少。本项目以氧化铁、氧化锰、氧化亚铜等有着潜在应用的金属氧化物纳米材料作为目标产物，以金属离子作为结构导向剂，在一定的配位剂（如氨水或者乙二胺等）存在的条件下，通过沉淀法、水热法、溶剂热法等液相法控制合成具有高能面暴露的金属氧化物纳米晶，探索金属离子在高能面暴露的纳米材料合成中的作用机制。并研究高能面暴露的金属氧化物纳米晶与暴露面密切相关的电催化、光催化、气敏等方面的性能，构建性能优越的催化、传感材料。

高能面暴露的纳米材料因为具有更高的反应活性，更多的空位，可以应用于光、电、声、磁等领域。然而高能面在晶体生长过程中很容易消失，在反应体系中引入一些添加剂，对纳米晶的表面控制起到很大的作用。针对这一问题，本项目以金属离子作为结构导向剂，控制合成了不同暴露晶面的氧化铁、羟基氧化铁、四氧化三钴、氢氧化钴等系列纳米材料。探讨了金属离子种类及用量、配位剂种类及用量、温度、反应时间等因素对反应体系的影响。考察了以金属离子作为结构导向剂，稳定高能晶面的作用机制，实现了系列高能面暴露的纳米材料的合成调控。并研究了与暴露晶面密切相关的磁性和电化学等方面的性能。磁性研究显示，高能晶面暴露的类立方体结构的氧化铁，属于缺陷磁性控制并且具有更高的磁性。这将为磁性器件的设计提供新思路。电化学性能研究显示金属离子控制合成的氧化铁、羟基氧化铁、四氧化三钴、氢氧化钴等系列纳米材料比普通暴露晶面的材料具有更高的电化学活性，有望在超级电容器、电催化剂等领域进行广泛的应用。