Noble metal nanoparticle-functionalized Zr-metal organic frameworks with excellent photocatalytic performance

Noble metal nanoparticles (NPs) functionalized MOFs are attractive materials for photocatalytic reactions, and outstanding catalytic performances can be expected, especially when they have intrinsically matched crystal faces between metals and MOFs. This study discovered that the photocatalytic oxidation of aromatic alcohols to aldehydes was enhanced over Au/UiO-66-NH₂ or Au/UiO-66 but suppressed over Pt loaded counterparts, whereas the reduction of Cr(VI) was boosted over both two catalysts. In reactions, the conversion of benzyl alcohol was 17.1% over UiO-66-NH₂ and 7.6% over UiO-66, and an enhanced conversion was obtained over Au/UiO-66-NH₂ (30.5%) and Au/UiO-66 (24.1%). However, the conversion was decreased over Pt/UiO-66-NH₂ (9.3%) and Pt/UiO-66 (<1%). Experimental results revealed strong correlations between Zr-MOFs and loaded metal NPs, as Zr centers promoted the formation of Pt(200) planes that suppressed the production of ·O₂^- intermediates to oxidize aromatic alcohols, whereas Pt(200) exhibited no effect on the Cr(VI) reduction triggered by photo-induced electrons. The findings in this study on constructing noble metal NPs functionalized Zr-MOFs catalysts with specially-matched crystal structures and on distinguishing photocatalytic mechanisms on oxidation of alcohols and reduction of Cr(VI) would provide valuable information for designer (photo)catalysts based on MOFs and their applications in such as catalysis and environmental remediation.