Sprayable, Large-Area Metal-Organic Framework Films and Membranes of Varying Thickness

Despite their huge potential for efficient molecular separation, the fabrication of membranes from metal-organic frameworks (MOFs) remains a major challenge. The powders obtained by the conventional solvothermal MOF syntheses are difficult to process, and as a result the fabrication of well-performing, large-area MOF-based membranes is still awaiting success. The deposition of MOF thin films suited for membrane applications is demonstrated by employing a step-by-step spray method. This method can be scaled up to obtain industrially relevant membrane areas and a continuous process is also possible. The performance of sprayed HKUST-1-based membranes by the separation of a binary H₂ /CO₂ mixture is also demonstrated. Furthermore, this approach enables the control of the MOF film thickness, and thus controlling the permeance and the selectivity of the membrane.