A microporous zirconia membrane with hydrogen permeance about 5×10

-8

mol·m

-2

·s

-1

·Pa

-1

H

2

/CO

2

permselectivity of ca. 14

and excellent hydrothermal stability under steam pressure of 100 kPa was fabricated via polymeric sol-gel process. The effect of calcination temperature on single gas permeance of sol-gel derived zirconia membranes was investigated. Zirconia membranes calcined at 350℃ and 400℃ showed similar single gas permeance

with permselectivities of hydrogen towards other gases

such as oxygen

nitrogen

methane

and sulfur hexafluoride

around Knudsen values. A much lower CO

2

permeance (3.7×10

-9

mol·m

-2

·s

-1

·Pa

-1

) was observed due to the interaction between CO

2

molecules and pore wall of membrane. Higher calcination temperature

500℃

led to the formation of mesoporous structure and

hence

the membrane lost itsmolecular sieving property towards hydrogen and carbon dioxide. The stability of zirconia membrane in the presence of hot steam was also investigated. Exposed to 100 kPa steam for 400 h

the membrane performance kept unchanged in comparison with freshly prepared one

with hydrogen and carbon dioxi

de permeances of 4.7×10

-8

and~3×10

-9

mol·m

-2

·s

-1

·Pa

-1

respectively. Both H

2

and CO

2

permeances of the zirconia membrane decreased with exposure time to 100 kPa steam. With a total exposure time of 1250 h

the membrane presented hydrogen permeance of 2.4×10

-8

mol·m

-2

·s

-1

·Pa

-1

and H

2

/CO

2

permselectivity of 28

indicating that the membrane retains its microporous structure.