Development of mixed-conducting oxides for gas separation

• Published in: Solid state ionics Vol. 108; no. 1; pp. 363 - 370
• Main Authors: Balachandran, U, Ma, B, Maiya, P.S, Mieville, R.L, Dusek, J.T, Picciolo, J.J, Guan, J, Dorris, S.E, Liu, M
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-05-1998; Elsevier Science
• Subjects: Ceramic membrane; Chemistry; Colloidal state and disperse state; Exact sciences and technology; Gas separation; General and physical chemistry; Membranes; Mixed-conductor; Oxygen permeation; Proton conduction; Ceramic membrane; Gas separation; Mixed-conductor; Proton conduction; Oxygen permeation; Oxygen; Cobalt Oxides; Ionic conductivity; Experimental study; Gaseous permeation; Membrane separation; Iron Oxides; Quaternary compound; Preparation; Proton conductivity; Membrane; Strontium Oxides; Ceramic materials
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/S0167-2738(98)00064-2

Mixed-conducting oxides have been used in many applications, including fuel cells, gas-separation membranes, sensors, and electrocatalysis. We are developing a mixed-conducting, dense ceramic membrane for selectively transporting oxygen and hydrogen. Ceramic membranes made of Sr-Fe-Co oxide, which has high combined electronic and oxygen ionic conductions, can be used to selectively transport oxygen during the partial oxidation of methane to synthesis gas (syngas, CO+H
2). We have measured the steady-state oxygen permeability of SrFeCo
0.5O
x
as a function of oxygen partial-pressure gradient and temperature. At 900°C, oxygen permeability was ≈2.5 scc·cm
−2·min
−1 for a 2.9 mm thick membrane and this value increases as membrane thickness decreases. We have fabricated tubular SrFeCo
0.5O
x
membranes and operated them at 900°C for >1000 h during conversion of methane into syngas. The hydrogen ion (proton) transport properties of Ba(Ce,Y)O
3−
δ
were investigated by impedance spectroscopy and open-cell voltage measurements. High proton conductivity and a high protonic transference number make Ba(Ce,Y)O
3−
δ
a potential membrane for hydrogen separation.