Impact of CaO-Modified γ-Al 2 O 3 Support on CO Oxidation Activity of Pt/LaFeO 3 Catalyst

In this study, we prepared Pt/29.3 wt % LaFeO on a commercial carrier of γ-Al O by inserting a CaO interlayer between LaFeO and γ-Al O (i.e., Pt/LaFeO /CaO/γ-Al O ) via atomic layer deposition. With the interaction between CaO and LaFeO , the Pt supported on LaFeO /CaO/γ-Al O demonstrated diverse dispersion characteristics, with regions showing well-dispersed Pt particles of approximately 2 nm, while others displayed some larger Pt nanoparticles. Interestingly, after redox treatments, the CO adsorption over Pt/LaFeO /CaO/γ-Al O was significantly attenuated, and high-resolution transmission electron microscope analysis on the Pt surface revealed the presence of FeO layers covering the Pt. Postoxidation, a thick FeO layer was generated on Pt, leading to the inertness of the catalyst toward CO oxidation. However, after reduction, a thinner FeO layer (approximately two atomic layers) developed on Pt, which facilitated the oxidation of CO through the Pt-FeO interface.