Reliable Strategy for the Covalent Bonding of MOFs to SiC Membranes for Ultrastable Noble Metal Capture in Harsh...

Silicon carbide (SiC) membranes combine exceptional chemical, thermal, and mechanical stability but suffer from surface inertness that precludes functionalization. Conversely, MOFs offer unmatched molecular selectivity but are typically powders, severely limiting their practical use. To address this, we develop a generalizable route to fabricate ultrastable MOF@SiC membranes via sequential oxidation and acidification, creating abundant Si-OH sites on SiC surfaces that covalently bond with Zr-MOF crystals; the bonding mechanism between MOFs and substrates has been extensively studied. Comparing modulators, acetic acid yields higher MOF crystallinity while hydrochloric acid produces uniform, defect-rich coatings with loadings up to 89.8 g m^-2. These composites endure prolonged ultrasonication and concentrated acid exposure with negligible MOF loss and exhibit wear resistance comparable to that of commercial SiC membranes. As a proof of concept for noble metal recovery, Pd(II) uptake from strongly acidic media follows rapid pseudo-second-order kinetics, achieves high adsorption capacity, and shows strong selectivity against competing ions. Thermodynamic analysis confirms a spontaneous, exothermic, and ordering adsorption process. By clarifying interfacial bonding and growth control via acid modulators, this work establishes a foundation for functionalizing inert ceramic membranes with MOFs, enabling scalable applications in separation, catalysis, and resource recovery under extreme conditions.