HKUST-1 membranes on porous supports using secondary growth

Here we report the synthesis of continuous HKUST-1 membranes on porous supports via the secondary (i.e., seeded) growth method. A new seeding technique (“thermal seeding”) was developed to strongly anchor HKUST-1 seed crystals on porous α-alumina supports. It was found critical to have both organic ligands and copper species in the seed suspension as well as to seed the crystals at elevated temperature. The HKUST-1 seed crystals on the supports were then hydrothermally grown into continuous HKUST-1 films. The formation of cracks and fractures in the films was prevented by controlling the cooling and the drying processes after crystallization. The permeation results of HKUST-1 membranes show moderate separation of hydrogen over other small gas molecules such as carbon dioxide, nitrogen, oxygen, and methane.