Porous zirconium-doped ceria showed great performance in the two-step solar thermochemical splitting of carbon dioxide into carbon monoxide and oxygen. The spherical zirconium-doped ceria is greatly desired for the fluidized-bedtype reactors because it has excellent moveability. In this paper, we demonstrate the fabrication and CO 2 -splitting performance of porous Zr-doped ceria microspheres of two compositions (Ce 1−x Zr x O 2 , x = 0.1 and 0.2). To process the porous microspheres, stable cerium-based liquid precursors were synthesized using the sol−gel method. One challenge was that the sol droplets would not solidify without solvent evaporation, when immersed in the immiscible hexadecane solution. Acrylamide (AM) was added to the precursor as the solidifier and poreforming agent. Upon polymerization of AM, the liquid was converted to solid, and thus droplets were converted to solid gel microspheres. After thermal decomposition and sintering, porous ceramic microspheres were obtained. Ceria and zirconia formed a solid solution. The CO 2 -splitting performance of porous Zr-doped ceria microspheres was characterized using thermogravimetric analysis (TGA). A higher Zr doping concentration (x = 0.2) resulted in a better CO production yield but slower reaction rate. Compared with reference Zr-doped ceria powder, the porous microspheres showed a higher CO production yield. After 12 800− 1400 °C thermal cycles, the microspheres maintained excellent individuality and sphericity. The specific surface areas of the porous Zr-doped ceria (Ce 0.8 Zr 0.2 O 2 ) microspheres had mild reduction.