Supramolecular Engineering of Metal–Organic Membranes with Metal‐Support Interactions for Nanoconfined Synergistic Catalysis

Abstract Continuous‐flow nanoconfined catalysis is crucial for rapid and efficient water purification but is challenging for traditional reactors. Supramolecular metal–organic membranes, with their intrinsically rich metal nodes, present promising opportunities for heterogeneous nano‐catalysis. However, achieving a uniform distribution and stabilization of exposed metal active sites remains a challenge. Here, a phosphotungstic acid (H 3 PW 12 O 40 : PW 12 ) modulated interfacial coordination strategy is introduced to engineer a thin palladium‐1,3,5‐triformylphloroglucinol (Pd‐Tp) nanofilm. The strong electrostatic‐dominated interaction between the fourfold hollow site of PW 12 and Pd II enables in situ confined reduction, facilitating the enhanced loading and uniform distribution of cluster‐shaped Pd‐PW 12 nanoparticles within the thin layer. The coordination between hydrophilic PW 12 and Tp leads to competition with PdCl 4 2‐ during film formation, giving rise to thinner, more hydrophilic, and loose‐structured membranes. Importantly, the PCM/NaBH 4 system exhibits a superior reducibility and electron transfer capacity, enabling efficient degradation of a range of organic contaminants, attributed to the robust metal‐support interactions. The PCM achieves a degradation rate constant of the target pollutant 4‐nitrophenol (97.8 ms −1 ), which is 175 times faster than that of the control HCM (0.56 ms −1 ). This study highlights the role of phosphotungstic acid in the microstructure modulation of metal–organic membrane and enhanced metal‐support interaction for nanoconfined synergistic catalysis.