Interfacial Microenvironment-Regulated Coordinate\nStructures Dictate the Metal–Organic Framework Facet Orientation\ntoward Efficient CO<sub>2</sub> Cycloaddition

The preparation of high-quality highly\noriented metal–organic\nframework (MOF) thin films is desirable for developing advanced functional\ndevices. However, the pathways for controlling the oriented growth\nof MOFs are largely unknown, and determining their microcosmic evolution\nat the complex solid–liquid interface remains a challenge.\nHerein, we investigate the critical early growth stage of typical\nHKUST-1 on the COOH-functionalized Au substrate utilizing a combination\nof in situ surface-enhanced infrared spectroscopy, X-ray photoelectron\nspectroscopy, and photoinduced force microscopy. Detailed molecular\nlevel information indicates that it is not only the COOH-terminated\nSAM itself but also the distinct interfacial structures of the first\nmetal coordinate layer and second ligand coordinate layer, which can\nbe regulated in aprotic and protic solvents, that dominate the initial\ngrowth behavior of MOF and thus lead to the [111], [100], and polycrystal\nfacet-oriented growth of HKUST-1. Moreover, the prepared HKUST-1 films\nexhibit a crystal facet-dependent catalytic rate in the chemical fixation\nof CO<sub>2</sub> into cyclic carbonate. Our observations provide\na reasonable guide for designing MOF-based anisotropic functional\nequipment.