Correlation of catalytic oxidation and ionic conductivity properties of nanostructured gadolinium-doped ceria.

Abstract

This paper reports the relationship between ionic conductivity and catalytic activity of ionic conductors based on gadolinium-doped ceria (GDC) at different temperatures. The samples have been characterized by transmission electron microscopy techniques, and the results indicated a highly homogeneous particle size, which confirmed their nanometric size. Afterward, the structure determined using X-ray diffraction analysis has been used to analyze the effect of dopant insertion. Lastly, ionic conductivity data were obtained using the impedance technique and were compared with the conversion rates of volatile organic compounds using GDC heterogeneous catalysts. The samples containing 15% gadolinium presented higher catalytic activity for the oxidation of n hexane (82,5%) as well as higher ionic conductivity at 400 ◦C (3.09 × 10− 4 S⋅cm− 1 ). An attempt is made to correlate conductivity and catalytic oxidation in terms of oxygen mobility, vacancies, and superoxide formation.