Interface Electronic Microenvironment Engineering in Pt@UiO-66 Composites for Regulating Interfacial Charge Transfer and Molecular Recognition.

Interface electronic microenvironment engineering has emerged as a promising yet underexplored strategy for regulating interfacial charge transfer and molecular recognition in functional nanocomposites. Herein, we report a mechanism-guided interface engineering approach by constructing a series of core-shell Pt@UiO-66-X composites (X = H, NH2, SO3H), in which linker functionalization is used to tune the local electronic and chemical environment surrounding Pt nanoparticles in a confined MOF matrix. Comprehensive experimental analyses supported by qualitative density functional theory (DFT) calculations indicate that the NH2-functionalized framework provides an electron-rich local environment together with a multipoint hydrogen-bonding network. This combined configuration favors AA adsorption on the functionalized UiO-66-NH2 model and facilitates Pt-assisted electrocatalytic response in the composite. Compared with electron-neutral and electron-withdrawing linkers, the NH2-functionalized composite exhibits stronger AA recognition, improved charge-transfer behavior, and reliable operational stability. As a representative electrochemical probe, ascorbic acid is employed to validate this proof-of-concept interface design strategy. The present study provides mechanistic insight into how linker electronic properties influence adsorption, molecular recognition, and electrochemical response in Pt@MOF composites, offering a potentially generalizable approach for related MOF-based interfacial systems rather than a fully universal design paradigm.