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

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 (H₃PW₁₂O₄₀: PW₁₂) 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 PW₁₂ and Pd^II enables in situ confined reduction, facilitating the enhanced loading and uniform distribution of cluster-shaped Pd-PW₁₂ nanoparticles within the thin layer. The coordination between hydrophilic PW₁₂ and Tp leads to competition with PdCl₄ ^2- during film formation, giving rise to thinner, more hydrophilic, and loose-structured membranes. Importantly, the PCM/NaBH₄ 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.