Microdroplet-Driven Synthesis of a Metal-Organic Framework Catalyst.

We report a room-temperature synthesis of copper-based metal-organic frameworks (Cu-MOFs) using microdroplet chemistry, offering a fast and energy-efficient alternative to conventional solvothermal methods that typically require high temperatures, extended reaction times, and suffer from inhomogeneous mixing. The unique microdroplet environment significantly accelerates reaction kinetics, enabling the formation of uniform octahedral crystals within 1 h at ambient conditions. Comprehensive characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), high-resolution mass spectrometry (HRMS), Brunauer-Emmett-Teller (BET) surface area analysis, and thermogravimetric analysis (TGA) confirmed the high crystallinity, thermal stability, and porous structure of the Cu-MOFs. Compared to conventionally prepared Cu-MOFs, those synthesized via microdroplet chemistry exhibit comparable surface areas with improved exposure of active sites. As a demonstration of their catalytic potential, the MOFs were employed in a microbubble-assisted air-water interface system for nitrogen fixation under ambient conditions. The system effectively converted atmospheric nitrogen into nitrate, showcasing the practical utility of these materials in green chemical transformations. This study shows that microdroplet and microbubble technologies are powerful and sustainable platforms for MOF synthesis and catalytic applications.