DMF体系中Cu2O球晶的制备及形貌分析

以N,N-二甲基甲酰胺(DMF)为溶剂,通过改变铜源和表面活性剂,调控反应参数,溶剂热条件下制备了三维十字形、空心及实心的Cu₂O球晶。利用XRD、SEM等表征手段,分析探讨了工艺条件变化对Cu₂O球晶形貌的影响。研究表明,随着DMF浓度的增大,体系的还原能力增强,Cu⁺增多,溶液的过饱和度增大,Cu₂O晶体集合体形态由晶体结构控制的各向异性与对称性的球晶逐渐向各向同性球晶演变。十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、聚乙烯吡咯烷酮(PVP)等表面活性剂有助于降低溶液的过饱和度,增加结晶质的表面扩散能力,有利于规则形态Cu₂O晶粒的形成。反应体系中,Cu(Ac)₂·H₂O水解生成的羧基与DMF中的甲酰基在高温下发生脱羧反应产生CO₂气体以及SDS发泡作用产生的气体是形成空心Cu₂O球晶的重要原因。

Preparation and Morphology Analysis of Cu2O Spherulites in DMF System

Cu₂O spherulites with different morphologies, such as three-dimensional cruciform, hollow and solid Cu₂O spherulites were prepared under DMF solvothermal conditions by changing copper source, surfactant and reaction parameters.The products were characterized by XRD and SEM, and the influences of process conditions on the morphology of Cu₂O spherulites were analyzed. The results indicate that with the increase of DMF concentration, the reduction capacity of the system is enlarged, Cu⁺ increases, and the solution supersaturation is enhanced. The spherulites with anisotropy and symmetry controlled by the crystal structure of Cu₂O crystal aggregates gradually evolve to isotropic spherulites. Surfactants such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and polyvinylpyrrolidone (PVP) are beneficial to reduce the supersaturation of the solution, the surface diffusion ability of the crystalline substance is improved. And the formation of Cu₂O grains tends to be regular. In the reaction system, the carboxyl group generated by the hydrolysis of Cu(Ac)₂·H₂O and the formyl group in DMF undergo decarboxylation reaction at high temperature to generate CO₂ gas and the gas generated by SDS foaming is an important reason for the formation of hollow Cu₂O spherulites.