甲酸在Nd-Fe-WO_4^(2-)氰桥混配物修饰铂电极上的电催化氧化  

Electrocatalytic Oxidation Behavior of Formic Acid at Platinum Elec-trode Modified with Nd-Fe-WO_4^(2-) Cyanide-bridged Mixed Complexes

作　　者：马永钧[1] 杨梅霞[1] 王伟峰[1] 周敏[1] 刘婧[1] 李婷婷[1] 陈慧[1] 

机构地区：[1]省部共建生态环境相关高分子材料教育部重点实验室甘肃省高分子材料重点实验室西北师范大学化学化工学院,兰州730070

出　　处：《化学学报》2011年第3期262-268,共7页Acta Chimica Sinica

基　　金：甘肃省自然科学基金(No.096RJZA117)资助项目

摘　　要：首次用电沉积法制备了Nd-Fe-WO42-氰桥混配物修饰铂电极(Nd-Fe-WO42-/Pt),并通过SEM和XRD技术分别表征了该修饰电极的表面形貌和修饰物的晶相结构.采用循环伏安法和计时电流法研究了甲酸在该修饰电极上的电氧化行为,实验发现甲酸在修饰电极上的电催化氧化电流密度与裸铂电极相比增加了10余倍,而且CV回扫阳极电位边界对属于吸附中间体的反扫峰形状有很大影响.此外,还研究了支持电解质中H+和SO24-浓度变化对甲酸氧化过程伏安特性的影响.结果表明:甲酸电催化主氧化峰的电位随H+浓度的增加而正向移动,随SO42-浓度增加而负向移动;当这两种离子共存时,H+的影响起主导作用.这表明甲酸在该修饰电极上电催化氧化反应的速率控制步骤是脱质子过程,而且SO42-/HSO-4在电极表面的吸附有利于氧化反应正向进行.以上结论为解释甲酸的电催化氧化机理提供了新的实验依据.同时,计时电流曲线和电极稳定性实验均表明该修饰电极对甲酸的电催化氧化过程具有良好的催化活性和抗毒化能力.A Nd-Fe-WO4^2- cyanide-bridged mixed complexes modified platinum electrode was success-fully prepared by using electrodeposition method for the first time. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were employed to characterize the morphology and crystalline lattice structure of the modified materials. Formic acid electrocatalytic oxidation behavior on this modified electrode was evaluated by means of cyclic voltammetry and chronoamperometry. The results indicated that the electro- catalytic oxidation current density of formic acid on modified electrode was about 10 times more than on bare Pt electrode, and CV anodic limit potential had significant effect on peak figuration of absorption intermediate in the reverse scan. Moreover, the influence of H^＋ and SO 2- concentration in electrolyte solution on the voltammetric characteristics of formic acid electrocatalytic oxidation was also studied, it showed that the main oxidation peak＇s potential increased with increasing H^＋ concentration, however, decreased with increasing SO4^2- concentration, but being coexistence of H^＋ and SO4^2-, the effect of H^＋ played a dominant role. This phenomenon revealed that the rate-determining step of electrocatalytic oxidation of for mic acid on modified electrode was correlative with de-protonation process, and the adsorption of SO 2-/HSO 4 would promote the forward oxidation reaction. These conclusions provided new experimental evidences for explaining the mechanism of formic acid electrocatalytic oxidation. Meanwhile, the electrode stability experiments as well as chronoamperometry also demonstrated that the newly developed modified electrode possessed much better electrocatalytic activity and tolerance to toxic intermediate contamination.

关 键 词：甲酸 电催化氧化 氰桥混配物 修饰电极 

分 类 号：O643.32[理学—物理化学]