Synergic Effect of Isolated Ce3+ and Ptd+ Species in UiO-66(Ce) for Heterogeneous Catalysis

Abstract

[EN] In this work, wehave synthesized through an efficient electrostaticdeposition a Pt single-atom catalyst (SAC) supported on a Ce-MOF.The basic solution employed in the impregnation process favors thedeprotonation of the hydroxyl groups allocated on the clusters thatcan easily interact with the cationic Pt species. The resulting material,denoted as Pt/UiO-66(Ce), shows an increment of Ce3+ content,as demonstrated by UV-vis and Ce L-3-edge XANES spectroscopy.These Ce3+ species and their corresponding oxygen vacanciesare able to accommodate very disperse Pt single sites. Moreover, PtL3-edge XANES and CO-FTIR spectroscopy confirm the cationicnature of the supported Pt & delta;+ (2+ < & delta; <4+). For comparison purpose, we have synthesized and characterizeda well-known Pt single-site catalyst supported on nanocrystallineceria, denoted as Pt/nCeO(2). Since thesimultaneous presence of Ce3+ and Pt & delta;+ on the MOF clusters were able to activate the oxygen molecules andthe CO molecule, respectively, we tested Pt/UiO-66(Ce) for the COoxidation reaction. Interestingly, this catalyst showed & SIM;six-foldincrement in activity in comparison with the traditional Pt/nCeO(2) material. Finally, the characterizationafter catalysis reveals that the Pt nature is preserved and that theactivity is maintained during 14 h at 100 & DEG;C without any evidenceof deactivation.