Supercritical Hydrothermal Synthesis of Organic‐Modified Ce_1‐xZr_xO_2‐δ (0≤x≤1) Nanoparticles as a Low‐Temperature Oxygen Carrier

Abstract In this study, organic surface‐modified Ce_1‐xZr_xO_2‐δ nanoparticles were synthesized using supercritical hydrothermal method. X‐ray diffraction and energy‐dispersive X‐ray spectroscopy analysis results indicated Zr intake into the CeO₂ lattice and vice versa. Results obtained from thermogravimetric analysis proved surface modification of Ce_1‐xZr_xO_2‐δ nanoparticles with carboxylic acids. Decreased particle size caused by surface modification along with induction of Zr into the CeO₂ lattice was found. Extraordinarily high oxygen storage capacity was obtained at low temperatures with a 70%‐Zr loading sample, which showed 337.0 μmol‐O/g at 200 °C and 530.1 μmol‐O/g at 250 °C. High oxygen mobility in the oxide originated from the small particle size and size control effects by surface modification, together with the great amount of defect sites enabled by Zr substitution. Taken together, these results suggest that this is a promising material for use as an oxygen carrier to support low‐temperature chemical looping process. Material performance as an oxygen carrier can be extracted by nano‐size and surface‐controlled effects, even exploring ordinary material composition, as ceria‐zirconia.