大尺寸金属氧族化合物超晶体的非线性调控合成、形成机理及性质研究

Fabricating macroscopic supercrystals has been regarded as an effective approach of achieving a broad range of applications of nanocrystals in areas such as photoelectricity, sensing and energy conversion. However, the current methods of nanocrystals assembly are still facing several challenges, which include the complex procedures involved, the small sizes of assembled body, irregular shapes, inferior stability and severer dependence on the deployed substrates. This project is proposed to develop new methods through the deployment of nonlinear electrochemical oxidation of transition metal on an oil-water interface, leading to the in-situ synthesis and simultaneous assembly of highly ordered large metal chalcogenide supercrystals (e.g., CoO、PbS、CdTe、SnS-PbS, etc.) . The proposed research will systematically examine the effects of different reaction medium, surface modification of molecular, polarization voltage/current density and temperature on the oscillatory behaviors of the metal and chalcogen , and subsequently investigate the correlation between the oscillation mode and frequency and the structure of thus-obtained supercrystals. The essence of nanocrystals synthesis and assembly which controlled by the nonlinear reaction system on oil-water interface will be studied to understand the formation mechanism of large supercrystals. In addition, the Enhanced Raman spectrum, photoelectric and thermoelectric properties of cadmium and lead based metal chalcogenides supercrystals will be also explored. Through the systematic investigation, this project will provide new insights and lay a solid foundation for future development of more economic, efficient and universal routes of preparing new structure, high performance supercrystals.

构建宏观尺度的超晶体被认为是实现纳米晶在光电、传感以及能源等领域实际应用的一条有效途径。但目前纳米晶的可控组装领域仍存在：组装工艺复杂，组装体尺寸偏小、形态不规则、稳定性不足以及对衬底的严重依赖性等难题。本课题拟发展一种基于过渡金属电溶解振荡反应的非线性动力学调控合成新方法，在油-水界面一步合成大尺寸、高规整的金属氧族化合物超晶体（如CoO、PbS、CdTe、SnS-PbS等)。研究反应介质、表面修饰分子、极化电压/电流等对金属（合金）电溶解振荡行为和氧族单质溶出行为的影响规律；洞察振荡模式与频率等对超晶体形成结构的影响；阐明纳米晶在非线性反应体系中两相界面上现场产生和原位组装形成大尺寸超晶体的机制和规律；研究大尺寸铅基、镉基等氧族化合物超晶体的光电、热电及增强拉曼光谱效应等性质。期望上述研究能建立一种经济、简便、普适的可控合成新方法，为发展新结构、高性能的大尺寸超晶体提供认识与实践基础。

金属氧族化合物纳米晶因其独特而丰富的光、电、热、磁等性质在光电、传感以及能源转换等领域有着重要的应用前景，可控高效的纳米晶合成技术一直以来是制约其实际应用的瓶颈。而利用非线性反应体系的自组织和自调控为无机纳米晶的高效成核、定向生长提供了新思路。为此，本项目发展了非线性电化学法合成了多种碲化物、氧化物、硫化物等氧族化合物纳米晶，并对其光、热、电性质及能量转化与存储性能等进行了深入的研究。主要工作包括：（1）建立了一种普适的基于非线性电化学技术促进无机纳米晶-导电共聚物紧密结合的新方法，量化制备了具有新颖核壳结构的TexSy@PANI无机-有机杂化纳米棒储锂固体，实现了高比能Li-TexSy电池长期循环的稳定性和优异的倍率性能。在0.1 A/g的充放电条件下，比容量达1141 mAh/g，是传统Li2Te电池理论容量的3倍。 （2）利用非线性电化学溶解金属阳极的方法宏量制备了CuxO/Cu2S纳米晶复合材料。不同的瞬态振荡模式可制备得到不同形貌的纳米晶体，将其应用在无酶葡萄糖检测中，检测限为10uM，检测灵敏度为2688 uA cm−2 mM−1。（3）发展了一步法快速宏量地可控合成了Cd0.8Zn0.2S-MoS2、CdS-MoS2-WS2、 CdS-MoS2-WS2@Pt等系列多组分过渡金属硫化物纳米异质结光催化剂材料，所得材料具有优异的光解水效率和稳定性。. 本项目顺利完成各项研究工作，在Energy Storage Mater.、Electrochimica Acta、 J. Raman. Spectrosc.、J. Phys. Chem. C、 Int. J. Hydrogen Energ.和Appl. Surf. Sci.等学术杂志上发表SCI论文8篇，其中影响因子大于2.0的6篇。申请专利6项，获授权发明专利2项。培养了4位研究生。