Tuning the Placement of Pt "Single Atoms" on a Mixed CeO2-TiO2 Support

Defect sites on the oxide supports can be used to anchor and activate "single-atom " catalysts (SACs). By engineering the anchoring sites for supporting SACs, one can alter their electronic and atomic structures which, in turn, define their activity, selectivity, and stability for catalytic reactions. To create and tune unique sites for Pt SACs on CeO2 support, in this work, we synthesized a system consisting of CeO2 decorated on TiO2 nano-oxides for supporting the Pt SACs and investigated the effect of Pt weight loading. A combination of multiple structural characterization methods including diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS) was employed to characterize the distribution of charge states of single atoms and evaluate the heterogeneity of their binding sites. We have found that the placement of Pt atoms can be tuned on a mixed oxide surface by changing the weight loading of Pt.