Pt-Promoted In₂O₃ Reduction and Reconstruction at the Pt/In₂O₃ Interface in CO₂ Hydrogenation Atmosphere

As an essential path toward the elucidation of the reaction mechanism, the capture of the catalytically active phase and its evolution has been the primary goal of mechanistic studies. Here, the physicochemical properties on In₂O₃ (111) and Pt/In₂O₃ (111) thin film model catalysts were tracked in CO₂ hydrogenation atmosphere under various pressures and temperatures by ambient pressure X-ray photoelectron spectroscopy (APXPS). The redox behaviours of surface Pt and In₂O₃, the formation and interconversion of reaction intermediates, and the structural dynamics at the topmost surface, as a consequence of the outward diffusion of InO_x species, nucleation of surface Pt nanostructures and the formation of PtInO_x species, were captured and analyzed. The reconstruction at the Pt/In₂O₃ (111) interface was also observed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and scanning electron microscopy (SEM) analysis. In-situ spectroscopic and structural analysis on a well-defined metal/metal-oxide interface offers a powerful means to probe the mechanistic details of the heterogeneous processes.