Ligand-mediated microenvironment tuning of UiO-66 to boost Pt activity for efficient VOC oxidation

Abstract

Maximizing the catalytic potential of metal–organic frameworks (MOFs) requires rational design and precise control over their microenvironment. Although modulator-assisted synthesis can introduce defects in MOFs, systematic understanding of how linker-to-modulator ratios affect the physicochemical and catalytic properties remains a critical gap. This work demonstrates a straightforward ligand modulation strategy to precisely engineer the properties of UiO-66 by varying the ratio of monodentate benzoic acid to bidentate terephthalic acid. Systematic characterization reveals that this approach effectively modulates defect density, surface area, electron density, and acidity of the support. An optimal modulator concentration produces a balance between defect creation and structural integrity, leading to enhanced electron density at Zr sites and favourable surface chemistry, which strengthens the chemical adsorption of toluene. When used as a support for Pt nanoparticles, the modulated microenvironment promotes superior metal dispersion, induces electron transfer from the support to Pt, and establishes a stable metal–support interaction. Consequently, the optimized Pt/UiO-66-10 catalyst exhibits exceptional activity for toluene oxidation. Furthermore, back-propagation neural network (BPNN) analysis quantifies the structure–activity relationships, revealing that tuning acid sites dominates the electronic and surface properties of Pt/UiO-66, and that metal–support interaction outweighs the Pt oxidation state in enhancing catalytic efficiency. This work not only provides a clear design strategy for high-efficiency MOF-based VOC oxidation catalysts, but also establishes a generalizable paradigm for microenvironment engineering of MOFs through straightforward ligand modulation.