Self-regenerating LaFeO3 perovskites with “tamed” Pt as robust catalysts for propylene and CO complete oxidation

Due to the difficulty of integrating platinum into the perovskite lattice, it is yet challenging to build robust Pt catalysts through the “exsolution” strategy. In this article, we showed that by simply inserting a 500 ℃ holding period in the calcination process of a precursor that obtained via citric acid-assisted sol-gel methods, a homogeneous Pt-incorporated LaFeO 3 perovskite could be synthesized. Further characterizations evidenced that a La 4 PtO 7 phase, probably derived from the reactions among Pt ensembles, gaseous O 2 , crystallized La 2 O 2 CO 3 and La(OH) 3 , played a key role in preserving the platinum in a “dissolved” state during perovskite crystallization. Based on this perovskite system, an “intelligent catalyst” with well-dispersed exsolved Pt nanoparticles and relatively large surface area was produced, which was not only highly reactive for the complete oxidation of C 3 H 6 and CO, but also immune to the sintering effects induced by aging treatments. The above observations provide a typical example on how the slight changes in synthesis significantly influence the structure-property relationship of the catalysts obtained via exsolution methods, and how to utilize these knobs to obtain practical catalysts.