【中文摘要】 氧化亚铜是一种重要的p型半导体材料,禁带宽度为2 eV,具有独特的光学和电学性质,在太阳能转换、气敏器件和催化等领域具有较大的应用价值。近二十年来,由于具有独特形貌和结构的微纳米材料逐渐被发现拥有优异的物理和化学性质,微纳米粉体材料的研发已成为粉体工业发展的重点,而其中对于氧化亚铜粉体的制备方法和工艺的研发更为受到材料科学家和工程师们的关注。本论文探索了新颖的氧化亚铜微纳米粉体的制备方法,从其形貌的形成机理和影响因素方面对粉体的形态控制进行研究。利用以下两种不同的合成路径成功实现了核壳结构和立方体,两种氧化亚铜粉体形貌的可控制备。以中间产物模板法为合成策略,设计了酒石酸辅助的水热结晶工艺,制备出粒径在2-5μm的核壳结构氧化亚铜粉体。在独立实验中,用扫描电子显微镜、X射线能量色散谱和X射线衍射对产物在不同合成时间下的形貌与结构进行了表征分析。推测其形成机理大致分为三个部分:(1)淡蓝色中间产物微米球的形成;(2)中间产物被还原转化为氧化亚铜微米球;(3)氧化亚铜球状粉体通过由内而外的奥氏熟化过程形成核壳结构。对于氧化亚铜微纳米粉体而言,这种同质核壳结构很少有人报道。该工艺所运用的中间产...更多物转化策略既推动了人们对水溶液中中空结构制备的理解,又对其他微纳米粉体的形态控制有很好的借鉴意义。以甲酸为还原剂,在水溶液环境中制备出立方体形貌的、粒径在4-9μm范围的氧化亚铜单晶粉体,并考察了氯离子和聚乙烯吡咯烷酮(PVP)的存在对其结晶形态的影响。利用扫描电子显微镜和X射线衍射对氧化亚铜产物进行表征,结果表明氯离子的存在使得最终产物的形貌由立方体变成截棱立方体,为进一步研究水溶液中微纳米粉末结晶形貌的控制因素提供了参考依据。
【英文摘要】 Cuprous oxide(Cu_2O) is an important p-type semiconductor with a direct band gap of 2 eV,and has wide applications in solar energy conversion,gas sensors and catalysis due to its unique optical and electronic properties.Over the last decade,extensive efforts have been focused on the research and development of micro/nano powders with specific morphologies and structures in the powder industry because of their distinctive properties. Moreover,it has even been a research hotspot that preparation methods and technologies of Cu_2O micro/nano powders.Herein,new synthetic routes to Cu_2O micro/nano powders have been designed and the formation mechanisms of the final shapes have been discussed.Two kinds of product morphologies,ie.,core-shell structure and cube,have been obtained by two different synthetic routes as described below.Starting from the intermediate-template strategy,we have designed a surfactant-free tartaric acid assisted hydrothermal approach for preparing homogenous core-shell... structured Cu_2O powders.The morphology and structure information of the as-grown crystals were characterized by Scanning Electron Microscope(SEM),energy dispersive X-ray(EDX) and X-ray powder diffraction(XRD).Furthermore,a formation mechanism has been revealed through the time-dependent experiments:(1) formation of intermediate microspheres;(2) reductive conversion of this template to Cu_2O;(3) inside-out Ostwald ripening of Cu_2O powders.As to Cu_2O,the core-shell structure is seldom reported.This intermediate template strategy not only can promote a better understanding of the designed synthesis of hollow-structured powders in aqueous solution,but help to make available functional powders in controllable morphologies.Uniform cubic Cu_2O micro powders have been synthesized via a hydrothermal method by reducing copper nitrate with formic acid,and the effect of Cl- ions and PVP on the morphologies of the products are also investigated.The products were characterized by SEM and XRD.The results reveal that the final shape of the Cu_2O powders change from cube to edge-truncated cube with the adding of Cl- ions into the initial solution.
【中文关键词】 氧化亚铜; 微纳米粉体; 形态控制
【英文关键词】 Cuprous Oxide; Micro/Nano Powders; Morphology Control
