Preparation of thin Pd-based composite membrane on planar metallic substrate

Development of a new porous metal support based on nickel and its application for Pd based composite membranes

“…The pretreatment procedure followed the method described by Li et al [5], including polishing and etching, followed by diffusion barrier coating with aluminum oxide sol particles of two different mean sizes of 2.5 mm and 0.3 mm. Two suspension sols A and B consisting of aluminum oxides were prepared using precursors of 2.5 mm mean particle size for sol A and 0.3 mm for sol B.…”

“…Many studies have examined the pre-treatment process for porous stainless steel to use it as a support for Pd-based membranes. Li et al [5,6] suggested several steps to pretreat supports, with alumina layers playing dual roles, serving as a modifier to reduce the pore size and the surface roughness of the support while also providing an inter-diffusion barrier between two layers. Nam and Lee [18] used sub-micron nickel powder to make the PSS surface smoother before plating a Pd-alloy membrane.…”

A tailor-made porous stainless steel support for a dense hydrogen separation membrane

“…Generally, dense metal membranes are PdeAg or PdeAu alloy either as foil type, which is unsupported, or as tubular or planar type, which is supported with porous materials such as alumina or stainless steel [2,3]. If being considered for their industrial applications, the Pd alloy membrane supported on the porous metal substrate is better choice, due to many advantages such as mechanical strength, thermal affinity with a Pd-based film, modularity with regular reactor parts, and low cost [4]. Based on these factors, tubular type, porous stainless steel supports have been widely adapted for membrane preparation [5,6].…”

“…The support's surface morphologies such as roughness, pore size, and degree of open-pores significantly affect membrane performance because they are directly related to membrane thickness. Therefore, proper surface modification processes to reduce roughness and largest pore size and also to keep the open-pores are needed, including mechanical and/ or chemical polishing, etching, coating, and filling [4,13]. In the case of the plate-type support, it is easy to modify its surface morphologies with polishing and/or filling methods.…”

“…The issues mentioned previously have been widely investigated to be overcome, but little attention has been paid to porous metal substrates even though membrane performance is directly related to the support properties [4]. The disk-shaped porous stainless steel substrate (DPSS) is a promising substrate for supporting the Pd-based layer due to its strength, versatility, and machinability [17].…”