| The idea of using hydrogen as an energy carrier in transportation and distributed industries necessitates an increasing research activities associated with all aspects of hydrogen, from production to end uses. As one of the most important operation units in the hydrogen production and gas-to-liquid processes, mixed conductor hydrogen separation membranes offer a simple and efficient way of separating hydrogen in a non-galvanic mode without electrodes and external circuitry. As the interfacial resistance will eventually dominate the total resistance of hydrogen separation, it is the goal of this research to gain a fundamental understanding of the surface kinetics, modify the membrane surface to reduce the surface polarization resistance, and improve the hydrogen permeation A composite of 40vol% nickel and 60vol% yttrium doped cerate (Ni-BCY) has been chosen as the membrane material. Results show that the surface kinetics is controlled by the charge-transfer process and changes with the surface composition and microstructure of the membrane. Surface modification layers (SMLs) with different compositions and microstructures are employed to reduce the polarization resistance. The stability and moisture effect in the feed gas on the membrane performance are also discussed in the thesis. |
