Oxygen Storage Capacity of Co-Doped SrTiO₃ with High Redox Performance

We prepared Co-doped SrTiO 3 materials with a high level of structural stability and investigated their oxygen storage capacity (OSC). These materials can release and store a large amount of oxygen in a reversible topotactic process. The oxygen storage amounts of SrTi 1– x Co x O 3−δ increased as the Co content was increased and was much larger than that of a conventional Pd/Ce 0.5 Zr 0.5 O 2 (Pd/CZ). X-ray absorption fine structure (XAFS) observation and iodometric titration revealed that doping Co into SrTiO 3 formed a higher Co valence (close to Co 4+ ) than that found in simple cobalt oxides. The high redox capability of this Co species contributed to the increased OSC of the Co-doped material. Moreover, Pd-loaded SrTi 1– x Co x O 3−δ was demonstrated to have an enhanced ability to purify exhaust gases under various oxygen concentrations because of their high OSC. We found that SrTiO 3 perovskite with a small amount of Co doping shows excellent structural stability and oxygen storage performance and is very effective as a catalyst support for the exhaust gas purification reaction.