Polyoxometalates-Mediated Selectivity in Pt Single-Atoms on Ceria for Environmental Catalysis

Optimizing the reactivity and selectivity of single-atom catalysts (SACs) remains a crucial yet challenging issue in heterogeneous catalysis. This study demonstrates selective catalysis facilitated by a polyoxometalates-mediated electronic interaction (PMEI) in a Pt single-atom catalyst supported on CeO₂ modified with Keggin-type phosphotungstate acid (HPW), labeled as Pt₁/CeO₂-HPW. The PMEI effect originates from the unique arrangement of isolated Pt atoms and HPW clusters on the CeO₂ support. Electrons are transferred from the ceria support to the electrophilic tungsten in HPW clusters, and subsequently, Pt atoms donate electrons to the now electron-deficient ceria. This phenomenon enhances the positive charge of Pt atoms, moderating O₂ activation and limiting lattice oxygen mobility compared to the conventional Pt₁/CeO₂ catalyst. The resulting electronic structure of Pt combined with the strong and local acidic environment of HPW on Pt₁/CeO₂-HPW leads to improved efficiency and N₂ selectivity in the degradation of NH₃ and NO, as well as increased CO₂ yield when inputting volatile organic compounds. This study sheds the light on the design of SACs with balanced reactivity and selectivity for environmental catalysis.