催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (8): 725-729.

• 研究论文 • 上一篇    下一篇

磷钼酸修饰的铂电极对二甲醚氧化的电催化作用

陈金伟,曾杰,姜春萍,王耀辉,赵北君,朱世富,王瑞林   

  1. 四川大学材料科学与工程学院, 四川成都 610065
  • 收稿日期:2007-08-25 出版日期:2007-08-25 发布日期:2011-08-19

Promotion Effect of Platinum Electrode Modified by Phosphomolybdic Acid on Dimethyl Ether Electrochemical Oxidation

CHEN Jinwei, ZENG Jie, JIANG Chunping, WANG Yaohui, ZHAO Beijun, ZHU Shifu, WANG Ruilin*   

  1. College of Materials Science and Engineering, Sichuan University, Chengdu 610065, Sichuan, China
  • Received:2007-08-25 Online:2007-08-25 Published:2011-08-19

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摘要： 利用循环伏安扫描法制备了磷钼酸(H3PMo12O40)修饰的铂电极. 在制备修饰电极时,随着扫描次数的增加,磷钼酸的氧化还原峰电流增大,但最终获得稳定的重现性好的磷钼酸修饰的铂电极. 通过循环伏安法研究了该修饰电极对二甲醚氧化的电催化反应. 结果表明,与未修饰的铂电极相比,磷钼酸修饰的铂电极电催化氧化二甲醚的起始氧化电位负移50 mV, 氧化峰电位负移35 mV, 氧化峰电流密度提高了1.86倍,这表明修饰电极的电催化活性有了很大的提高. 同时,电位负扫时,二甲醚在425 mV(vs SCE)处出现氧化峰,表明二甲醚在修饰电极上的电氧化机理可能发生了改变. 实验还发现,制备修饰电极时,降低扫速会提高还原物质杂多蓝的吸附量,但过多的修饰物质会降低铂的活性位数目,反而降低了对二甲醚氧化的电催化作用.

关键词: 铂, 磷钼酸, 循环伏安法, 二甲醚, 电氧化, 燃料电池, 电催化

Abstract: A Pt electrode modified by H3PMo12O40(PMo12) was prepared by cyclic voltammetry. The preparation process showed that more PMo12was adsorbed on the surface of the bare Pt electrode when the number of scanning increased at the beginning, but finally the total adsorbed amount reached saturation. The electrooxidation of dimethyl ether (DME) was studied on the surface of the PMo12-modified Pt electrode by cyclic voltammetry. The results showed that the Pt electrode modified by PMo12had higher activity for DME oxidation, and its onset potential had a negative shift of 50 mV. The peak current density was enhanced more than 1.86 times with the negative shift of 35 mV on its peak potential, compared with the unmodified electrode. There was a positive current peak at the reverse scan, which was different from the literature. This might indicate the change of the mechanism for DME oxidation on the modified electrode surface. The peak could response methanol oxidation, and the methanol was more likely the mid-product of DME oxidation at the PMo12-modified Pt electrode. The experimental results also showed that the decrease of scan rate put more PMo12on the surface of the bare Pt electrode, however, the activity for DME oxidation was reduced due to the decrease of the effective sites on the surface of the Pt electrode.

Key words: platinum, phosphomolybdic acid, cyclic voltammetry, dimethyl ether, electrooxidation, fuel cell, electrocatalysis