Microfluidics for synthesis and morphology control of hierarchical porous covalent organic polymer monolith

The hierarchical porous monoliths are important in enhancing diffusion efficiency and reducing pressure drop in heterogeneous catalysis. Here, a practical way to synthesize hierarchical porous covalent organic polymer (COP) monolith by using droplet microfluidic is proposed. The interconnected macro pores (up to ∼ 130 nm) were created within intrinsic microporous COP structures by the further condensation of COP particles in the confined microdroplets. Concentration, flow rate ratio, catalyst, etc., were screened to figure out the superior condition for producing different hierarchical porous COP monolith in microfluidic. Rod-like and spherical monolith with gradient sizes were controllable synthesized to satisfy the requirements of different packing density for practical applications. Significantly, our homemade single microreactor is able to produce the spherical hierarchical porous COP monolith with a high space-time yield of 413 kg·m⁻³·day⁻¹ at optimized condition, which provides a promising scale-up method to synthesize COP monoliths for but not limit to industrial heterogeneous catalysis.