高等学校化学学报

高等学校化学学报 ›› 1996, Vol. 17 ›› Issue (2): 274.

• 论文 • 上一篇    下一篇

包覆硬脂酸膜α-Fe2O3超微粒子的光谱及光电化学研究

杨迈之, 张雯, 蔡生民   

  1. 北京大学化学与分子工程学院, 北京 100871
  • 收稿日期:1995-01-26 出版日期:1996-02-24 发布日期:1996-02-24
  • 通讯作者: 杨迈之,女,39岁,博士,副教授.
  • 作者简介:杨迈之,女,39岁,博士,副教授.
  • 基金资助:

    国家科学技术委员会“863”高科技项目

UV-Vis Spectral and Photoelectrochemical Studies on the α-Fe2O3 Ultrafine Particles with a Layer of Stearic Acid

YANG Mai-Zhi, ZHANG Wen, CAI Sheng-Min   

  1. COllege of Chemistry and Molecular Engineering, Peking University, Beijing 100871
  • Received:1995-01-26 Online:1996-02-24 Published:1996-02-24

PDF (PC)

摘要： 采用相转移法制备了以硬脂酸(ST)修饰的α-Fe2O3超微粒子,测量了其紫外-可见吸收光谱。随着粒子尺寸的减小,光谱吸收阈值发生红移,表现出介电限域效应。用循环伏安法和光电流～电势曲线研究了介电限域效应对α-Fe2O3超微粒子电化学及光电化学性质的影响。循环伏安结果表明,表面修饰ST的α-Fe2O3超微粒子电化学可逆性较裸露粒子好。光电流-电位的关系表明,超微粒子周围的介质性质也影响了微粉的光电化学性质。

关键词: &alpha, -Fe2O3超微粒子, 介电限域效应, 光电化学

Abstract: The α-Fe2O3 ultrafine particles coated with a layer of stearic acid(ST) were prepared by phase transfer method.There is a significant red shift of optical absorption band edge with the decrease of size particles which exhibits the dielectric confinement effect. The effect of dielectric confinement on the electrochemical and photoelectrochemical properties of α-Fe2O3 ultrafine particles was investigated by using cyclic voltammetry and photocurrent measurement.The coating layer with smaller dielectric constant decreases the shielding to the electric lines,so that the platinum electrode deposed by the coated particles is more electrochemically reversible than by the naked particles.Acathodic photocurrent is observed with both kinds of particles in the region of-600～267 mV,but there is a fine distinction in the cathodic photocurrent of two kinds of electrodes,which comes from the dielectric confinement effect.Aweak anodic photocurrent is observed in the potential region of>260 mV.

Key words: α-Fe2O3 ultrafine particles, Dielectric confinement effect, Photoelectrochemistry

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