Characterization of CeO2 microspheres fabricated by an ultrasonic spray pyrolysis method

CeO2 is one of the main catalysts for solid oxide fuel cell (SOFC). It is critical to find a green and cost-effective fabrication method for CeO2 at scale. In this study, the CeO2 microspheres were prepared by one-step ultrasonic spray pyrolysis of cerium chloride solution at 700 °C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) study demonstrate that the prepared CeO2 microspheres exhibit a particle size of 0.01–1.08 μm with a mean particle size of 0.23 μm, and more than 94% of the particles have a diameter less than 0.5 μm. But the presence of residual Cl in the fabricated CeO2 microspheres blocks the active sites and leads to the significant degradation of SOFC performance. The formation mechanism and distribution of residual Cl in the fabricated CeO2 microspheres were systemically studied. The water washing method was shown to effectively reduce the residual Cl in the CeO2 microspheres. Overall, this work provides a clean manufacturing process for the preparation of SOFC electrode/electrolyte materials.