Effect of surface oxidation on the surface condition and deuterium permeability of a palladium membrane

Abstract

Oxidation and deoxidation of a Pd membrane was conducted in a quartz tube oven in a temperature range of 23–500°C. The micromorphology and chemical composition of the Pd membrane surface was characterized using scanning electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Micropores and PdO began to form on the Pd membrane surface after oxidation at 240°C for 1h and their quantity increased gradually with increasing temperature. A rough Pd membrane surface was obtained when the temperature rose to 500°C. The PdO on the Pd membrane surface was completely deoxidized once more using H2 at room temperature, but the rough surface morphology caused by oxidation remained. The deuterium permeability of the Pd membrane was tested using special equipment in the China National Key Laboratory and the results indicated that the rough Pd membrane surface had higher deuterium permeability than the original membrane. The improved deuterium permeability could be attributed to the higher Pd membrane surface area, which provided deuterium atoms with more adsorption sites and dissociation sites.