CeO2–CoOx mixed oxides: Structural characteristics and dynamic storage/release capacity

CoOx–CeO2 mixed oxides with increasing Co/(Ce + Co) atomic ratio (1–20 mol%) are prepared by sol–gel method and characterized by means of by X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) and Hydrogen temperature-programmed reduction (H2-TPR) techniques. The dynamic oxygen storage capacity (DOSC) is investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement reveal that the solubility limit of cobalt oxides in the CeO2 was 5 mol% based on Co/(Ce + Co). The lattice parameters have been observed to experience a decrease followed by an increase due to the influence of the maximum solubility limit of cobalt oxides in the CeO2. TPR analysis reveals that Co introduction into ceria strongly modifies the textual and structural properties, which influenced the oxygen handling properties. DOSC results reveal that Ce-based materials containing Co oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicates that the calculated apparent kinetic parameters obey the compensation effect.