摘要
通过循环伏安(CV)、恒电流充放电和电化学阻抗谱(EIS)等测试方法,研究了电化学改性石墨电极对硫酸溶液中Fe3+/Fe2+的电催化性能与准电容特性.结果表明:由于电化学改性石墨电极表面存在大量的含氧活性官能团,使其对Fe3+/Fe2+的氧化还原反应具有极高的电催化性能,并具有可逆反应过程特征.在含有0.5mo·lL-1Fe3++0.5mo·lL-1Fe2+的2.0mo·lL-1H2SO4溶液中,其表观面积比电容是不含铁离子硫酸溶液的1.808倍,达到2.157F·cm-2;同时,铁离子浓度的增大也能够进一步提高其电容量.Fe3+/Fe2+电对的加入增加了充放电时间,有效提高了电化学电容器(EC)的电容存储容量和高功率特性.电化学阻抗谱测试同样证实体系具有明显的电容特性.因此,可以利用电化学改性石墨电极表面的含氧活性官能团和溶液中Fe3+/Fe2+的氧化还原特性来共同储存和释放能量.
The electrocatalytic performance and pseudocapacitive characteristics of a modified graphite electrode（MGE）with Fe 3＋ /Fe 2＋ in H 2 SO 4 solution were studied by cyclic voltammetry（CV）,constant current charge-discharge measurements,and electrochemical impedance spectroscopy（EIS）.The results showed that the MGE had high electrocatalytic activity and good reversible characteristics for the redox reaction of Fe 3＋ /Fe 2＋ because of a large quantity of oxygen-containing functional groups on the MGE surface.The apparent area-specific capacitance of the MGE in 2.0 mol·L -1 H 2 SO 4 solution containing 0.5 mol·L -1 Fe 3＋ and 0.5 mo·lL -1 Fe 2＋ reached 2.157 F·cm -2 ,which was almost double that in 2.0 mo·lL -1 H 2 SO 4 without Fe 3＋ / Fe 2＋ .Meanwhile,increasing the concentration of iron ions increased the capacitance of the MGE.The addition of Fe 3＋ /Fe 2＋ made the charge-discharge curves more symmetric and change more slowly,which increases the charge-discharge time,and effectively improves the capacitive energy storage and high power performance for an electrochemical capacitor（EC）.The obvious capacitive characteristics were confirmed by EIS,and are attributed to the oxygen-containing functional groups on the MGE and the Faraday redox reaction of Fe 3＋ /Fe 2＋ in the thin electrolyte layer.Therefore,the oxygen-containing functional groups on the MGE surface and redox reaction of Fe 3＋ /Fe 2＋ can be used together for energy storage and release.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2012年第3期603-608,共6页
Acta Physico-Chimica Sinica
基金
山东省博士基金(BS2010NJ018
BS2011NJ019)
中央高校基础科研基金(201022006)资助项目~~
关键词
电化学改性石墨电极
铁离子
电催化
电化学电容
准电容
Modified graphite electrode
Iron ion
Electrocatalysis
Electrochemical capacitor
Pseudo-capacitance
