Method of making a gas separation system

A method of making a gas separation system, said method comprising the steps of:

• (a) providing a porous metal support having a first surface and a second surface with each said surface being opposed to the other to thereby define a support thickness, said first surface of said support having a measurable initial surface roughness and an initial mean pore size;
• (b) contacting said first surface of said support with a first particulate material having a first mean particle size that is less than said initial mean pore size to form a first coated surface on a coated support, said first coated surface having a measured first surface roughness;
• (c) removing excess first particulate material from said first coated surface;
• (d) contacting said first coated surface with a second particulate material having a second mean particle size that is less than said first mean particle size to form a second coated surface on said coated support, said second coated surface having a measured second surface roughness;
• and
• (e) removing excess second particulate material from said second coated surface;
• and
• (f) contacting said second coated surface with a third particulate material having a third mean particle size that is less than the second mean particle size to form a third coated surface having a third measured surface roughness;
• wherein the measured surface roughness of said third coated surface is less than the measured surface roughness of said first coated surface.