Controllable synthesis of magic cube-like Ce-MOF-derived Pt/CeO2 catalysts for formaldehyde oxidation

Abstract

Controllable synthesis of MOFs with desired structures is of great significance to deepen the understanding of the crystal nucleation-growth mechanism and deliver unique structural features to their derived metal oxides with target catalytic applications. In this study, NH₂-Ce-BDC with morphology similar to a second-order magic cube (mc) is facile synthesized via H⁺ mediation in nucleation and growth stages. The pertinent variables that can greatly influence the formation of magic cube-like structures (MCS) were investigated, in which the concentric diffusion field was found to be one of the key factors. Upon calcination, the derived CeO₂ inherits unique gullies and grooves located on the pristine MOFs surface, which is quite useful for atomic layer deposition (ALD) of platinum (Pt) nanoparticles because of strong interaction with MOF-derived CeO₂ (mc-CeO₂). XPS, H₂-TPR, Raman, and in situ DRIFTS characterization results show that there is a stronger interaction between Pt and mc-CeO₂ in mc-Pt/CeO₂ compared with c-Pt/CeO₂ that is derived from the well-developed cubic Ce-MOFs. Furthermore, Pt²⁺ ions, hydroxyl oxygen, and oxygen defects in mc-Pt/CeO₂ account highly for exemplary catalytic activity toward HCHO oxidation.