【摘要】 NaVO₃在Na₂CO₃-K₂CO₃熔盐体系中可原位催化电还原CO₂制备高附加值碳材料,对Na₂CO₃-K₂CO₃-NaVO₃体系熔盐结构进行研究有助于明晰电极过程机理和优化反应条件.本文采用拉曼光谱学和量子化学计算（基于Gaussian和Molclus程序）相结合的方法探究了1 073 K下Na₂CO₃-K₂CO₃-NaVO₃熔盐体系的离子结构.结果表明,在该熔盐体系中,除了存在CO₃^2-以外,还存在由CO₃^2-和VO₃^-发生反应生成的VO₄^3-,而不存在VO₃^-;VO₄^3-所属C₁空间点群,其中V—O键的对称伸缩振动模对应的拉曼特征峰位于802 cm^-1处;随着体系中NaVO₃质量分数由5%增加至15%,熔盐中VO₄^3-的相对含量急剧增加,而CO₃^2-的相对含量相应地减少.更多还原

【Abstract】 In the molten Na₂CO₃-K₂CO₃, NaVO₃ can catalyze the in-situ electroreduction of CO₂ to prepare high value-added carbon-based products. Studying the molten salt structure of Na₂CO₃-K₂CO₃-NaVO₃ system contributes to understand the electrode process mechanism and optimize the reaction conditions. The ionic structure of Na₂CO₃-K₂CO₃-NaVO₃ molten salt system at 1 073 K was investigated by a combination of Raman spectroscopy and quantum chemistry calculation using Gaussian and Molclus programs. The results show that VO₄^3-generated by the reaction of CO₃^2-and VO₃^-exists in the melts, apart from the presence of CO₃^2-, but VO₃^-doesn’t exist. VO₄^3-belongs to C₁ point group symmetry, and the band located at 802 cm^-1 in the Raman spectrum is caused by the symmetrical stretching vibration of the V—O bond in VO₄^3-. As the mass fraction of NaVO₃ in the system increases from 5% to 15%, the relative content of VO₄^3-increases dramatically, while that of CO₃^2-decreases accordingly in the molten salts.更多还原