Modifying the oxygen adsorption properties of YBaCo4O7 by Ca, Al, and Fe doping

The doping effect of Ca, Al, and Fe on the oxygen adsorption properties of YBaCo4O7 was investigated by thermogravimetry (TG) method. It was found that the original YBaCo4O7 oxygen adsorption properties can be modified greatly by Ca, Al, and Fe doping. Ca doping in Y sites eliminates the oxygen adsorption at low temperature (*300 C) but the oxygen adsorption properties at high temperature is almost unchanged. Minor Al doping in Co sites eliminates the oxygen adsorption hump at high temperature, but the hump at low temperature is preserved. Fe appearance in YBaCo3Al1-xFexO7 seems to weaken the effect of Al doping, so the oxygen hump at high temperature emerges again. The doping effect was discussed based on elements valence, binding energy between cations and oxygen ions, and distortion of crystal structure.