Large-area synthesis of nanoscopic catalyst-decorated conductive MOF film using microfluidic-based solution shearing.

Conductive metal-organic framework (C-MOF) thin-films have a wide variety of potential applications in the field of electronics, sensors, and energy devices. The immobilization of various functional species within the pores of C-MOFs can further improve the performance and extend the potential applications of C-MOFs thin films. However, developing facile and scalable synthesis of high quality ultra-thin C-MOFs while simultaneously immobilizing functional species within the MOF pores remains challenging. Here, we develop microfluidic channel-embedded solution-shearing (MiCS) for ultra-fast (≤5 mm/s) and large-area synthesis of high quality nanocatalyst-embedded C-MOF thin films with thickness controllability down to tens of nanometers. The MiCS method synthesizes nanoscopic catalyst-embedded C-MOF particles within the microfluidic channels, and simultaneously grows catalyst-embedded C-MOF thin-film uniformly over a large area using solution shearing. The thin film displays high nitrogen dioxide (NO2) sensing properties at room temperature in air amongst two-dimensional materials, owing to the high surface area and porosity of the ultra-thin C-MOFs, and the catalytic activity of the nanoscopic catalysts embedded in the C-MOFs. Therefore, our method, i.e. MiCS, can provide an efficient way to fabricate highly active and conductive porous materials for various applications.