Continuous Synthesis of Optimized Ni ₃ (HITP) ₂ With Broad Spectrum of Morphologies via Automated Microfluidic Ammonia Manipulation Platform

ABSTRACT The morphology of metal–organic frameworks (MOFs) critically governs their electronic, catalytic, and transport performance. However, continuous synthesis of morphology‐tunable MOFs remains challenging because scaffold formation is influenced by and highly sensitive to subtle reaction condition variations, involving temperature, concentration, mixing rate, and pH. Here, we present a programmable reactor for iterative synthesis of MOFs via Microfluidics (PRISMM) that enables precise and continuous synthesis of Ni 3 (HITP) 2 and Pt‐decorated Ni 3 (HITP) 2 with a broad spectrum of morphologies, ranging from disordered aggregates to well‐defined nanosheets, thereby allowing a wide distribution of porosity. By independently regulating ammonia permeation through microfluidic chips and dynamically adjusting synthesis parameters, this platform achieves fine control over ligand deprotonation kinetics and nucleation in a continuous and reproducible manner. The resulting Ni 3 (HITP) 2 exhibits optimized morphology and enhanced porosity, while incorporation of platinum maximizes Pt accessibility and exposure, facilitates rapid mass transfer, and improves active‐site utilization. In ammonia borane dehydrogenation, Pt@Ni 3 (HITP) 2 delivers 3 equivalents of hydrogen with over 99% purity, yielding a turnover frequency of 2323 min −1 . This work establishes an automated pathway for MOF morphology manipulation, thereby demonstrating the strong potential of programmable microfluidic synthesis for morphology‐directed design of MOFs in energy, catalytic, and broader applications.