An oxygen pool from YBaCo4O7-based oxides for soot combustion

Abstract

Soot, often referred to as black carbon emitted from diesel engines, is not only a particulate matter pollutant but also a light-absorbing agent that may affect global climate, but can be effectively controlled using a catalytic diesel particulate filter (DPF). A new YBaCo₄O_7+δ-type oxygen storage material is reported as an effective catalyst for soot combustion. Isotopic isothermal reactions demonstrate the activation of gaseous oxygen and subsequent oxygen storage and reaction/desorption during an oxidation process. High activity and structural stability are achieved by the substitution of Co with Al and Ga to form YBa(Co_0.85Al_0.075Ga_0.075)₄O_7+δ. The specific rates at 300 °C of YBaCo₄O_7+δ and YBa(Co_0.85Al_0.075Ga_0.075)₄O_7+δ, normalized by surface areas, are an order of magnitude higher than those of CeO₂-based oxides. This kind of oxygen-storage material acts as an oxygen pool, which ensures that the accumulated soot on a DPF can be promptly combusted.