Constructing asymmetric active Fe3+-OV-Mn4+ sites at the Fe2O3-MnO2 interface for low-temperature soot combustion

Abstract

Promoting the generation of reactive oxygen species by adjusting the strength of metal-oxygen bonds and constructing interfacial active sites has been proven to effectively enhance soot combustion. Herein, Fe2O3-MnO2 bimetallic oxides (FMO) with a heterogeneous interface were prepared using a simple PBA (Prussian blue analogue) derivation method. The catalysts exhibited superior active oxygen content and strong electron transport capacity. The Fe3+-OV-Mn4+ structure, an asymmetric oxygen vacancy, formed at the interface, and the strength of the metal-oxygen bonds was further regulated at different calcination temperatures, significantly activating lattice oxygen. The FMO-HA catalyst showed the highest activity, with soot conversion temperatures reaching 90 % at 289 °C under tight contact and 382 °C under loose contact. This work offers a dual regulatory strategy to enhance the production of reactive oxygen species and proposes a rational design for high-performance catalysts for soot combustion.