Facile surface modification of porous stainless steel substrate with TiO2intermediate layer for fabrication of H2-permeable composite palladium membranes

The increasing demand in compact hydrogen separators greatly stimulated the investigation and utilization of composite palladium membranes. Porous stainless steel (PSS) tubes were chosen as substrate material in this study, and a novel process of carbon-assisted solid-state sintering was introduced to modify the PSS surface with a TiO2 layer. A Pd/TiO2/PSS membrane with a Pd thickness of 6 µm was successfully fabricated via electroless plating. Scanning electron microscopy (SEM), metallographic microscopy, X-ray diffraction and pore-size analyses were performed for material characterizations. As measured by H2/N2 single-gas testing, the fabricated Pd/TiO2/PSS membrane is permeable and selective to hydrogen, and it was stable during a time-on-stream of 100 h under 450°C.