The oxygen vacancy structure of ceria plays a key role in its performance as a favored material for catalysis applications. Here, we develop an understanding of the effects of Pt loading on the structural evolution of ceria nanorods under redox gas environments that mimic real automotive catalytic converters. In situ neutron scattering studies under redox flow reveal that both CeO2 and Pt–CeO2 nanorods share a bulk fluorite structure with the presence of surface Frenkel-type oxygen defects. However, Pt–CeO2 nanorods are more easily reducible than CeO2 rods as evidenced by an increased concentration of Ce3+, determined by NAP-XPS. Importantly, this work finds no evidence of oxygen vacancy ordered surface reconstruction which has been reported in earlier ex situ investigations. Thus, this work highlights the discrepancy between ex situ and in situ structural observations and emphasizes the need for robust in situ investigations of catalysts to develop industrially relevant materials.

Our recent work has reported that higher propylene selectivity and improved stability can be achieved by combining redoxactive VO x and basic In 2 O 3 for CO 2 -assisted oxidative dehydrogenation of propane (CO 2 -ODHP). In the present work, we continued to explore the stability and regenerability of V/In catalysts. In particular, our interest lies in identifying the effect of mono-and polyvanadate on catalytic performance and regenerability. A V/In catalyst with an increased proportion of monovanadate was prepared using the Schlenk line under moisture-free conditions (V/In−S), while the fully polymerized vanadate catalyst was prepared through a regular impregnation (V/In) for comparison. The Schlenk-line-prepared catalyst, namely, V/In−S, not only exhibits a 17−30% enhanced propylene yield at high temperatures (500−540 °C) over V/In but also presents improved stability and regenerability with nearly 88% activity recovered after regeneration in O 2 . Detailed characterizations have been performed to reveal the catalyst structure−performance relationship, including chemisorption (NH 3 /CO 2 -temperature-programmed desorption, NH 3 /CO 2 -TPD), H 2 -temperature-programmed reduction (H 2 -TPR), and spectroscopic studies [Raman spectroscopy, UV−vis diffuse reflectance spectroscopy (UV−vis DRS), near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS), and high-sensitivity low-energy ion scattering (HS-LEIS)]. Characterization results demonstrate that compared with polyvanadates, monovanadates lead to strengthened interaction with In 2 O 3 and a more stabilized V/In surface and subsurface, as well as improved redox properties of VO x . These advantages give rise to the observed enhancement in activity, stability, and regenerability. These findings advance the understanding of the relationship between the activity/stability and the molecular structure of surface oxide species (vanadia) and the interplay between acid−base interactions and redox properties of mixed metal-oxide catalysts for efficient CO 2 -ODHP.