Temperature-Dependent Dynamics of Superoxide and Peroxide Anions in Hydrocarbon Catalytic Oxidation Over Single-Atom Pt Catalysts.

Understanding the properties of reactive oxygen species (ROS) is crucial for efficient oxidation catalyst design, yet their dynamics during oxidative reactions are still unclear. Herein, using a CeZrO2-supported single-atom Pt catalyst (PtSA/CeZrO2), we studied temperature-dependent behaviors of superoxide (O2 •-) and peroxide (O2 2-) anions and how multiple ROS are involved in the catalytic oxidation of mixed hydrocarbons. We show that O2 •- species, having an unpaired electron and a Pt-O-O structure, accounts for surface reactivity at lower temperatures, which is critical to toluene ring-opening below 200°C. At higher temperatures (200°C-450°C), O2 •- desorbs, while the O2 2- anion, anchored by an oxygen vacancy (Vo) in the form of Pt-O-O@Vo, exhibits high stability and activity, promoting initial propane activation. Through the "relay" cooperation of O2 •- and O2 2- species, the PtSA/CeZrO2 (Pt loading of 0.4 gPt/L) achieves complete removal of mixed toluene and propane at 450°C, 150°C lower than on a commercial high-Pt loading PtNP/CeZrO2 catalyst (0.9 gPt/L). Our study advances the understanding of the dynamics and synergism of multiple ROS in mixed hydrocarbon oxidation process and paves the way for the development of next-generation catalysts suited for a broad operational temperature window.