Oxygen storage and release behavior of delafossite-type CuFe1−xAlxO2

• Published in: Journal of materials science 2013, Vol.48 (23), p.8077-8083
• Main Authors: Kato, Sumio, Suzuki, Sho, Kawashima, Ryunosuke, Ogasawara, Masataka, Wakabayashi, Takashi, Nakahara, Yuunosuke, Nakata, Shinichi
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Materials Science; Polymer Sciences; Solid Mechanics
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-013-7620-2

Delafossite-type solid solution, CuFe 1− x Al x O 2 , was synthesized and its oxygen storage capacity (OSC) was investigated under oxidation/reduction cycle using a pulse injection method. CuFe 1− x Al x O 2 was synthesized by heating at 1100–1150 °C in N 2 flow. OSC values for x  = 0.1 and 0.3 were larger than that for x  = 0 above 500 °C, indicating that substitution of Fe 3+ by Al 3+ improved OSC. For x  = 0.5–1.0, temperature at which OSC increased steeply shifted upward. Results of X-ray diffraction (XRD) after the thermogravimetry and differential thermal analysis (TG–DTA) measurement in air for CuFe 1− x Al x O 2 ( x  = 0–0.7) indicated that oxidative decomposition of delafossite phases to CuO and spinel-type phase occurred. In addition, Cu reduction temperature estimated by the temperature programmed reduction using H 2 (H 2 -TPR) shifted to higher temperature with increasing Al content. The XRD results of the samples after H 2 and O 2 /He pulse injection suggested that the oxygen storage/release behavior was caused by reversible oxidation/reduction process between CuFe 1− x Al x O 2 delafossite and (Fe 1− x Al x ) 3 O 4 spinel phase +Cu.