A robust core-shell silver soot oxidation catalyst driven by Co3O4: Effect of tandem oxygen delivery and Co3O4-CeO2 synergy

In this work, tandem oxygen delivery systems were built by coating cube-like Co 3 O 4 with Ag/CeO 2 , which exhibited high soot oxidation activity that overwhelmed the Fe 2 O 3 -based catalysts. The results of TPR and activity tests indicated that a large amount of Co 3 O 4 lattice oxygen could be transferred into O x − with the assistance of Ag/CeO 2 . These active oxygen species accelerated the oxidation of soot and NO at low temperature. Furthermore, the Co 3 O 4 -CeO 2 synergy facilitated Co 3+ → Co 2+ transformation during reactions, resulting in boosted NO conversion and thereby NO 2 -assisted soot combustion at mild and high temperatures. Given the Ag/Co 3 O 4 @CeO 2 -type catalysts were low-cost, hydrothermally stable and could be fabricated via co-precipitation methods easily, they were highly promising for application in both gasoline and diesel particulate filters.