Robust Ru/Ce@Co Catalyst with an Optimized Support Structure for Propane Oxidation

Abstract

Short carbon chain alkanes, as typical volatile organic compounds (VOCs), have molecular structural stability and low molecular polarity, leading to an enormous challenge in the catalytic oxidation of propane. Although Ru-based catalysts exhibit a surprisingly high activity for the catalytic oxidation of propane to CO₂ and H₂O, active RuO_x species are partially oxidized and sintered during the oxidation reaction, leading to a decrease in catalytic activity and significantly inhibiting their application in industrial processes. Herein, the Ru/Ce@Co catalyst is synthesized with a specific structure, in which cerium dioxide is dispersed in a thin layer on the surface of Co₃O₄, and Ru nanoparticles fall preferentially on cerium oxide with high dispersity. Compared with the Ru/CeO₂ and Ru/Co₃O₄ catalysts, the Ru/Ce@Co catalyst demonstrates excellent catalytic activity and stability for the oxidation of propane, even under severe operating conditions, such as recycling reaction, high space velocity, a certain degree of moisture, and high temperature. Benefiting from this particular structure, the Ru/Ce@Co (5:95) catalyst with more Ce³⁺ species leads to the Ru species being anchored more firmly on the CeO₂ surface with a low-valent state and has a strong potential for adsorption and activation of propane and oxygen, which is beneficial for RuO_x species with high activity and stability. This work provides a novel strategy for designing high-efficiency Ru-based catalysts for the catalytic combustion of short carbon alkanes.