Oxygen Activation through β-Bi2O3 and Ultrafine CeO2 Interactions to Promote Catalytic Soot Combustion

Herein, we report the high performance of Bi2O3 interacted with ultrafine CeO2 nanoparticles (NPs) for soot oxidation. With the increased Bi content, Bi2O3 can be tuned from the amorphous phase to beta-Bi2O3 and finally to alpha-Bi2O3. The ultrafine CeO2 NPs possessing abundant defects and large surface area are beneficial to forming beta-Bi2O3. Our kinetic results show that the quantity of active oxygen species at the Bi-O-Ce interface is the determining factor for soot oxidation. Compared with other Bi2O3 phases, the interaction between beta-Bi2O3 and CeO2 can readily generate a larger quantity of active surface oxygen species with a higher turnover frequency. Consequently, the Bi2Ce8 catalyst containing beta-Bi2O3 exhibits high activity and stability for soot oxidation and has the potential to be applied in real operations. Our discoveries provide insights into controlling active phase transformation and tuning interaction of metal oxides for various catalyst systems.