Asymmetric and hierarchical porous carbon membranes prepared by a single-step soft-templated method

A facile single-step method was developed to prepare carbon membranes derived from novalac phenol–formaldehyde resin as a carbon precursor and Pluronic® F108 (EO132–PO50–EO132) and polyethylene glycol as the soft template. In a single sintering-step, an asymmetric membrane was formed with a very thin top layer followed mesoporous interlayer supported on a macroporous support. The top separating layer was characterized by closely packed carbon particles while the interlayer is consisted of disordered and loosely packed carbon particles, containing large gaps thus leading to hierarchical structures. The carbon membrane achieved H2/N2 permselectivity up to 92, far above the Knudsen selectivity suggesting the molecular sieving mechanism.