中山大学学报(自然科学版)2011，Vol.50Issue(3)：68-73,6.
Keggin型铬取代杂多离子PW11O39Cr(Ⅲ)(H2O)4-的电化学性质
The Electrochemical Properties of the Keggin-type Cr(Ⅲ)- Substituted Heteropolyanion PW11O39Cr(Ⅲ)(H2O)4-
摘要
Abstract
Electrochemical properties of the PW11 Cr(Ⅲ)O394-;( PW11Cr) in H3PO4-HAc-H3BO3 ( pH 2.16) buffer were investigated in detail by cyclic voltammetry, AC voltammograms and alternating current impedance analyses. The result of cyclic voltammogram showed that three pairs of redox waves were observed on the glassy carbon (GC) electrode in H3PO4-HAc-H3BO3 (pH 2. 16) buffer solution containing 1.0 mmol·L-1 PW11Cr. The pair of quasi-reversible wave at 1.30/0. 631 V belonged to Cr( V )/Cr( Ⅲ ) two-electron redox, while the two pairs of reversible waved at - 0. 553/- 0. 505 V and -0.782/-0.725 V belonged to W-O skeleton two-electron redox. When the pH value increased, the peak potential of the three pairs of two-electron waves shifted negatively and the peak current decreased, which showed that H+ was involved in the electrode process. In addition, the difference of peak potential between anode and cathode for each pair of waves increased, which showed reversibility of electrode process decreased. The diffusion coefficient DO of PW11Cr calculated from linear relationship of peak current of the first skeleton reduction wave versus square root of potential scan rate was 4. 4 × 10-6 cm2 · s-1 in H3PO4-HAc-H3BO3 ( pH 2.16) buffer. AC impedance of Cr ( Ⅲ ) was a semicircle without Wahlberg line occurred at high frequency, which showed the anode oxidation process was controlled by heterogeneous charge transfer dynamics. The dynamic parameter k°of electrode process was calculated from the relationship between phase angle and frequency. AC impedance of PW11 Cr keleton reduction revealed the electrode process was controlled by diffusion.关键词
Keggin型铬取代杂多离子/循环伏安/交流伏安/交流阻抗Key words
Keggin-type Cr-substituted heteropolytungstate/ cyclic voltammetry/ AC voltammetry/ AC impedance分类
化学化工引用本文复制引用
华英杰,王崇太,李天略,毛彦超,黄永龙,彭婷,于丹..Keggin型铬取代杂多离子PW11O39Cr(Ⅲ)(H2O)4-的电化学性质[J].中山大学学报(自然科学版),2011,50(3):68-73,6.基金项目
国家自然科学基金资助项目(20963003) （20963003）
海南省重点科技资助项目(090803) （090803）
海南省自然科学基金资助项目(509009) （509009）
吉林省科技发展计划资助项目(20090595) （20090595）
国家大学生创新资助项目(091165820) （091165820）
