Synthesis of a CeO2/Co3O4 catalyst with a remarkable performance for the soot oxidation reaction

Abstract

A highly active catalyst based on two metal oxides, CeO₂/Co₃O₄, for the low temperature soot oxidation at low temperatures is reported. This catalyst was produced by depositing cobalt oxide by the method of deposition−precipitation with urea onto CeO₂ microstructures obtained by the hydrothermal method using urea and citric acid as precipitating agents. Catalytic experiments were performed by temperature programmed combustion, in a fixed-bed microreactor, under loose and tight contact conditions, using Printex-U (Evonik) as the model soot. The results showed that the CeO₂/Co₃O₄ material presented an enhanced activity for the soot oxidation reaction (50% soot conversion at 287 °C) compared with CeO₂ (50% soot conversion at 337 °C) and Co₃O₄ (50% soot conversion at 360 °C) catalysts separately. The catalytic activity for the CeO₂/Co₃O₄ catalyst is higher than the ones reported for Ce–Co based catalysts, tested under similar conditions, for soot oxidation (reduced by 46 °C the lowest temperature reached for the 50% soot conversion).