Electron beam irradiation defective UiO-66 supported noble metal catalysts for binary VOCs removal: Insight into the synergistic degradation mechanism of mutual promotion

Electron beam (EB) irradiation has emerged as an effective post-synthetic strategy to modify the structural properties of metal-organic frameworks (MOFs), offering enhanced defect engineering and improved active site dispersion. In this study, UiO-66-100, pretreated under the optimal EB irradiation dose of 100 kGy with abundant structural defects, was selected as the support to synthesize supported noble metal catalysts M-UiO-66-100 (M = Pt, Pd, Ru, Ag, Au). The catalytic performance of M-UiO-66-100 was evaluated by toluene and 2-propanol degradation. Among them, Pt-UiO-66-100 exhibited superior performance for toluene oxidation (T 90  = 187 °C), while Pd-UiO-66-100 showed excellent activity for 2-propanol degradation (T 90  = 229 °C). Both catalysts exhibited distinct physicochemical properties and adsorption behaviors in single-component Volatile organic compound (VOC) systems. Interestingly, further studies revealed that both Pt- and Pd-based catalysts displayed significantly enhanced catalytic activity for toluene and 2-propanol mixture oxidation, highlighting a mutual promotion effect. VOC- temperature-programmed desorption/oxidation (TPD/TPO) and thermal desorption-gas chromatography–mass spectrometry (TD-GC–MS) results elucidated the mutual promotion effect that compared with single VOC systems, Pd-UiO-66-100 and Pt-UiO-66-100 produce fewer intermediates during mixed VOC degradation, which reduced the accumulation of intermediates on the catalysts surface, released the surface active sites, and accelerated their mineralization. This work provides a rational design approach for EB-modified MOF-supported catalysts and deepens the insights into the synergistic oxidation mechanism in mixed-VOC systems.