Synthesis of Co3O4 catalysts with different morphologies and their excellent catalytic performance for soot combustion†

Abstract

Soot particles released from diesel engines have resulted in significant environmental pollution and have been widely recognized as an important factor for haze weather conditions. Soot emissions can be effectively mitigated using catalytic purification technologies, which necessitate the development of high-efficiency catalysts. Co₃O₄ catalysts with flower-, rod-, urchin-, sheet-, and cube-like morphologies were prepared via a hydrothermal method and were analyzed using characterization methods including XRD, SEM, and H₂-TPR. Compared to the other synthesized catalysts, the urchin-like (Co₃O₄-U) catalyst exhibited better redox ability, stronger oxygen adsorption and activation ability, and the ability to convert NO into NO₂. Therefore, the Co₃O₄-U catalyst displayed the best catalytic activity for soot combustion, with T₁₀, T₅₀, and T₉₀ values of 274 °C, 327 °C, and 359 °C, respectively. Moreover, based on the characterization and catalytic performance results, the reaction mechanisms for the Co₃O₄-U catalyst were proposed. The Co₃O₄-U catalyst possesses advantages such as a simple preparation process, economic feasibility, and excellent catalytic performance.