摘要
采用交流阻抗等电化学技术研究了SiO2在等物质的量CaCl2和NaCl熔盐中的电脱氧反应.交流阻抗谱表明,SiO2电脱氧为单质硅的反应是两步反应,与循环伏安曲线上的两个还原电流峰相符合.电脱氧后电极产物的XRD分析证实,在反应体系存在着下列中间物:SiO,CaSiO3和Ca2SiO4.通过拟合交流阻抗谱与等效电路,得到SiO2电脱氧反应的电荷传递电阻、双电层电容和活化能.在低电压范围内,电荷传递电阻和活化能均随阴极电压的增加而降低,表明SiO2电脱氧反应的速度控制步骤是电荷传递过程.本研究工作对提高SiO2电脱氧过程的电流效率有重要意义.
AC impedance spectrum was used to study the electro-deoxidation reaction of silicon dioxide in the equalmolar molten salt CaCl2 and NaCl. The AC impedance spectra showed that the electro-deoxidation reaction of silicon dioxide is a two-step reaction and corresponding to the two reduction current peaks in the cyclic voltammetry curve. In the XRD pattern the intermediates SiO, CaSiO3 and Ca2SiO4 were found in the reaction system. By fitting the AC impedance spectra with equivalent circuits, the charge transfer resistance, double layer capacitance and activation energy during the reaction were obtained. In the low voltage range the charge transfer resistance and activation energy decrease with increasing cathodic voltage which implies that charge transfer is the rate control step of the electro-deoxidation of SiO2. The results of the study are important to improve the current efficiency in the electro-deoxidation process of silicon dioxide.
出处
《东北大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2007年第4期537-540,共4页
Journal of Northeastern University(Natural Science)
基金
国家自然科学基金资助项目(50674027)
关键词
二氧化硅
电脱氧
交流阻抗谱
机理
silicon dioxide
electro-deoxidation
AC impedance spectrum
mechanism
