摘要
以ESR为主要研究手段 ,研究了一种最可几粒径为 9.8nm的ZrO2 样品在室温不同气体 (He,H2 ,O2 ,空气 ,湿空气 )中及经不同温度处理后ZrO2 中Zr3 + 中心信号的变化 .根据ZrO2 样品中Zr3 + 浓度在室温下对于介质气体中O2 分压改变的响应极快及Zr3 + 浓度在室温下对于介质气体变化可逆性等特点提出 ,ZrO2 中Zr3 + 中心绝大多数存在于样品的表面上 ,Zr3 + 是ZrO2 晶体表面上那些O2 -配位不饱和的Zr原子点位 .ZrO2 表面上ESR活性Zr3 + 中心的数目与其上氧吸附平衡有关 .由ESR法对ZrO2 样品中Zr3 + 中心的定量和对ZrO2 晶体的粒度分析 ,推测ZrO2 表面上Zr3 + 中心是那些位于ZrO2 微晶的晶角处O2 -配位不饱和的Zr原子 .
The changes of signal intensity of Zr3+ centers of ZrO2 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 ZrO2, about 1 X 10(-7) Mol. g(-1) of Zr3+ centers were detected, which are the oxygen coordinatively unsaturated Zr ions. It is found that the concentration of Zr3+ center changes reversibly and quickly with O-2 partial pressure in various gases. This result reveals that the Zr3+ centers are mainly on the surface of ZrO2 and their concentration is related to O-2 adsorption equilibrium. Based on the quantitative ESR analysis and particle size data of ZrO2, the present authors propose that the oxygen coordinatively unsaturated Zr3+ centers should be located at the crystal corners of ZrO2 initial particles.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第4期622-626,共5页
Acta Chimica Sinica
基金
国家自然科学基金 (No .2 99770 4)资助项目
