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化学学报
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化学学报 ›› 2002, Vol. 60 ›› Issue (4): 622-626. 上一篇    下一篇

研究论文

ZrO_2表面上Zr~(3+)中心上的O_2吸附平衡

王新平;赵沁;蔡天锡   

  1. 大连理工大学化工学院,大连(116012)
  • 发布日期:2002-04-15

Adsorption Equilibrium of O_2 on Zr~(3+) Center Located on the Surface of Zirconia

Wang Xinping;Zhao Qin;Cai Tianxi   

  1. State Key Laboratory of Fine Chemicals, Dalian University of Technology,Dalian(116012)
  • Published:2002-04-15

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以ESR为主要研究手段，研究了一种最可几粒径为9.8 nm的ZrO_2样品在室温不 同气体（He，H_2，O_2，空气，温空气）中及经不同温度处理后ZrO_2中Zr~(3+)中 心信号的变化。根据ZrO_2样品中Zr~(3+)浓度在室温下对于介质气体中O_2分压改 变的响应极快及Zr~(3+)浓度在室温下对于介质气体变化可逆性等特点提出， ZrO_2中Zr~(3+)中心绝大多数存在于样品的表面上，Zr~(3+)是ZrO_2晶体表面上那 些O~(2-)配位不饱和的Zr原子点位。ZrO_2表面上ESR活性Zr~(3+)中心的数目与其 上氧吸附平衡有关。由ESR法对ZrO_2样品中Zr~(3+)中心的定量和对ZrO_2晶体的粒 度分析，推测ZrO_2表面上Zr~(3+)中心是那些位于ZrO_2微晶的晶角处O~(2-)配位 不饱和的Zr原子。

关键词: 氧化锆, 吸附, 电子自旋共振, 氧

The changes of signal intensity oF Zr~(3+) centers of ZrO_2 nanopowder in various gases (He, H_2, O_2, air and wet air) and at different annealing temperatures have been studied by means of ESR. On the surface of ZrO_2, about 1 * 10~(-7) mol·g of Zr~(3+) centers were detected, which are the oxygen coordinatively unsaturated Zr ions. It is found that the concentration of Zr~(3+) center changes reversibly and quickly with O_2 partial pressure in various gases. This result reveals that the Zr~(3+) centers are mainly on the surface of ZrO_2 and their concentration is related to O_2 adsorption equilibrium. Based on the quantitative ESR analysis and particle size data of ZrO_2, the present authors propose that the oxygen coordinatively unsaturated Zr~(3+) centers should be located at the crystal corners of ZrO_2 initial particles.

Key words: ZIRCONIUM OXIDE, ADSORPTION, ESR, OXYGEN

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