O3 titration for synthesis of Pt-Pd core-shell structural catalyst and its catalytic performance on C-H bond activation

Abstract

A novelty catalyst synthesis method is introduced in this investigation, which employs O3 pulse to induce a segregation of Pd-Pt species to synthesize Pt-Pd core shell structural catalyst. In Pt-Pd alloy, O3 releases highly active oxygen (O*) species (O3→O2 + O·), which combine with Pd species or Pt species selectively. This combination induces a relative migration between Pd and Pt atoms, forming Pt-core@PdO-shell structural catalyst, which meets the thermodynamic stability of Pt-Pd alloy. Core shell structural catalyst displays a better catalytic performance for C-H bond activation. Experimental results indicate core-shell structural catalyst produces more highly active oxygen species than alloy catalyst does. These highly active oxygen species activate C-H bond in alkanes, contributing to a higher catalytic reactivity. In addition, the interaction between Pt-core and PdO-shell lowers the binding energy of ionic Pd species, which facilitates the release of reactive oxygen species.