Ni-Al2O3 composite membranes for hydrogen separation

This work presents fabrication of Ni-Al2O3 composite membranes for hydrogen separation, by Solid State Reaction and an impregnation method. The role of Al2O3 precursor is also investigated. In fact, ?-Al2O3 and ?-Al2O3 have been used as alumina source. Nickel source is Ni(NO3)2o6H2O [ ]. By Solid State Reaction procedure, mixtures containing ?-Al2O3 or ?-Al2O3 and Ni 10 wt% are ball milled with a properly amount of ethanol in ZrO2 jar. After 12 h of effective mixing, the mixtures are dried in air at 100 °C for 24 h. The so obtained powder are grounded and uniaxially pressed at 195MPa in circular shape of about 1,3 cm. Different heat treatments at 900 °C, 1100 °C and 1300°C were tested to understand how this can affect the final phases and sintering behaviour. With impregnation method, raw ?-Al2O3 and ?-Al2O3 are ball milled with 5 wt% of Polyvinyl alcohol for 12 h in ZrO2 jar. After 2 h at 85°C, powders are grounded, uniaxially pressed at 195MPa in circular shape of about 1,3 cm and heat treated (1000 °C and 1200 °C). After that, a Ni(NO3)2o6H2O solution is introduced into sintered pellet in order to obtain final amount of Ni 10 wt%. The as obtained pellet were heat treated at 900°C to remove nitrate and water re-siduals. After preparation, the membranes obtained by both methods were reduced at 1000°C for 2h in hydrogen atmos-phere. Phases and morphologies were analyzed by means of XRD and SEM analyses respectively. References [1] S. Vichaphund, D. Atong, Journal of Materials Science & Technology 26 (2010) 589.