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本文运用原位电子电导技术,测定了La-Cu-O复合氧化物分别在O_2,CO气氛下的电导瞬间应答曲线。从O_2吸附使电导率升高,CO吸附使电导率降低直至吸附平衡。以及从电导率值,说明在273～573K温度区间为P型半导体。还分别测定了在真空及空气,一氧化碳气氛下的平衡电导率和温度的关系以及不同的O_2,CO进样模式下电导率随温度的变化。发现在预吸附氧后再引入CO的情况下,在403K,443K和533K出现了三次电导率的突降。结合XPS测定中Om结合能的数据,分析了三个突变温度点可能为表面上不同能量的吸附氧所引起,并表明在此温度范围,反应以Eley-Ridcal机理为主。
In this paper, the in-situ electronic conductance technique was used to determine the conductance transient response curves of La-Cu-O composite oxides under O 2 and CO atmospheres respectively. Conductivity increases from O 2 adsorption and CO adsorption decreases conductivity until adsorption equilibrium. And from the conductivity value, indicating that the temperature range of 273 ~ 573K P-type semiconductor. The relationship between the equilibrium conductivity and temperature under vacuum and air and carbon monoxide atmosphere and the change of conductivity with temperature under different O_2 and CO modes were also measured respectively. It was found that in the case of introducing CO after pre-adsorption of oxygen, a dip of conductivity of three times occurred at 403K, 443K and 533K. Based on the data of Om binding energy in XPS analysis, it is analyzed that the three mutation temperature points may be caused by adsorbed oxygen with different energy on the surface, and the reaction is dominated by Eley-Ridcal mechanism in this temperature range.