Morphologically controllable spinel catalysts CuCo2O4 for boosting catalytic oxidation of toluene

Cobalt-based spinels have been extensively tried as catalysts for the oxidation of toluene, but they are not yet superior in terms of catalytic activity. Morphological engineering is a viable way to enhance catalytic activity. In this work, four catalysts with different morphologies (CuCo2O4 Spheres, Flowers, Sheets, and Rods) were prepared by solvothermal/hydrothermal methods. The morphology transformation was achieved by simple adjustment of the precursor solution. The addition of surfactant NH4F contributed to the formation of special morphology. The highest activity was seen in the toluene oxidation of Spheres (T50 =202 °C, T90 =218 °C). Characterization results indicated that the underlying reasons for efficient activity were high surface area, the abundance of Co3+ and Oads, and enhanced low-temperature reducibility.