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

Abstract

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 CeO2 surface. Electrons are transferred from 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 degradation of NH3, N2 selectivity in the NO conversion, and 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 applications.